Configuring Clocking

This chapter provides information about configuring clocking on the Cisco ASR 901 Series Aggregation Services Router.

Configuring Clocking

This chapter provides information about configuring clocking on the Cisco ASR 901 Series Aggregation Services Router.

Restrictions

  • External interfaces like Building Integrated Timing Supply (BITS) and 1 Pulse Per Second (1PPS) have only one port. These interfaces can be used as either an input interface or output interface at a given time.
  • The line to external option is not supported for external Synchronization Supply Unit (SSU).
  • Time-of-Day (ToD) is not integrated to the router system time. ToD input or output reflects only the PTP time, not the router system time.
  • Revertive and non-revertive modes work correctly only with two clock sources.
  • BITS cable length option is supported via platform timing bits line-build-out command.
  • There is no automatic recovery from out-of-resource (OOR) alarms. OOR alarms must be manually cleared using clear platform timing oor-alarms command.
  • If copper Gigabit Ethernet port is selected as the input clock source, the link must be configured as a IEEE 802.3 link-slave, using synce state slave command.
  • BITS reports loss of signal (LOS) only for Alarm Indication Signal (AIS), LOS, and loss of frame (LOF) alarms.
  • The clock source line command does not support loop timing in T1/E1 controllers. However, the clock can be recovered from T1/E1 lines and used to synchronize the system clock using the network-clock input-source priority controller E1/T1 0/x command.
  • Adaptive clocking is not supported in Cisco ASR 901 router.
  • The show network-clocks command is not supported in Cisco ASR 901 Router.

  • Do not use network-clock synchronization command while configuring 2dmm, as it is not supported. If you proceed with the unsupported configuration, it will show junk values.

Configuring Network Clock for Cisco ASR 901 Router

Cisco ASR 901 router supports time, phase and frequency awareness through ethernet networks; it also enables clock selection and translation between the various clock frequencies.

If Cisco ASR 901 interoperates with devices that do not support synchronization, synchronization features can be disabled or partially enabled to maintain backward compatibility.

The network clock can be configured in global configuration mode and interface configuration mode:

Configuring Network Clock in Global Configuration Mode

Complete the following steps to configure the network clock in global configuration mode:

Procedure

  Command or Action Purpose
Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

network-clock synchronization automatic

Example:


Router(config)# 
network-clock synchronization automatic

Enables G.781-based automatic clock selection process. G.781 is the ITU-T Recommendation that specifies the synchronization layer functions.

Step 4

network-clock eec {1 | 2 }

Example:


Router(config)# network-clock eec 1

Configures the clocking system hardware with the desired parameters. These are the options:

  • For option 1, the default value is EEC-Option 1 (2048).
  • For option 2, the default value is EEC-Option 2 (1544).
Step 5

network-clock synchronization ssm option {1 | 2 {GEN1 | GEN2 } }

Example:


Router(config)# network-clock synchronization ssm 
option 2 GEN1

Configures the router to work in a synchronized network mode as described in G.781. The following are the options:

  • Option 1: refers to synchronization networks designed for Europe (E1 framings are compatible with this option).
  • Option 2: refers to synchronization networks designed for the US (T1 framings are compatible with this option). The default option is 1 and while choosing option 2, you need to specify the second generation message (GEN2) or first generation message (GEN1).
Note 
Network-clock configurations that are not common between options need to be configured again.
Step 6

network-clock hold-off {0 | 50-10000} global

Example:


Router(config)# network-clock hold-off 
75 global

Configures general hold-off timer in milliseconds. The default value is 300 milliseconds.

Note 
Displays a warning message for values below 300 ms and above 1800 ms.
Step 7

network-clock external slot/card/port hold-off {0 | 50-10000}

Example:


Router(config)# network-clock external 
3/1/1 hold-off  300

Overrides hold-off timer value for external interface.

Note 
Displays a warning message for values above 1800 ms, as waiting longer causes the clock to go into the holdover mode.
Step 8

network-clock wait-to-restore 0-86400 global

Example:


Router(config)# network-clock external 
wait-to-restore 1000 global

Sets the value for the wait-to-restore timer globally.

The wait to restore time is configurable in the range of 0 to 86400 seconds. The default value is 300 seconds.

Caution 

Ensure that you set the wait-to-restore values above 50 seconds to avoid a timing flap.

Step 9

network-clock input-source priority { interface interface-name slot/port | top slot/port | {external slot/card/port [t1{sf| efs| d4} | e1 [crc4| fas| cas[crc4] | 2048k | 10m]}}

Example:


Router(config)# network-clock input-source 1 
nterface top 0/12

Example:

Example for GPS Interface
Router(config)# network-clock input-source 1 
external 0/0/0 10m

Configures a clock source line interface, an external timing input interface, GPS interface, or a packet-based timing recovered clock as the input clock for the system and defines its priority. Priority is a number between 1 and 250.

This command also configures the type of signal for an external timing input interface. These signals are:

  • T1 with Standard Frame format or Extended Standard Frame format.
  • E1 with or without CRC4
  • 2 MHz signal
  • Default for Europe or Option I is e1 crc4 if the signal type is not specified.
  • Default for North America or Option II is t1 esf if signal type is not specified.
Note 
The no version of the command reverses the command configuration, implying that the priority has changed to undefined and the state machine is informed.
Step 10

network-clock input-source priority controller [ t1 | e1] slot/port

Example:


Router(config)# network-clock input-source 10 
controller e1 0/12

Adds the clock recovered from the serial interfaces as one of the nominated sources, for network-clock selection.

Step 11

network-clock revertive

Example:


Router(config)# network-clock revertive

Specifies whether or not the clock source is revertive. Clock sources with the same priority are always non-revertive. The default value is non-revertive.

In non-revertive switching, a switch to an alternate reference is maintained even after the original reference recovers from the failure that caused the switch. In revertive switching, the clock switches back to the original reference after that reference recovers from the failure, independent of the condition of the alternate reference.

Step 12

network-clock output-source system priority {external slot/card/port [t1{sf| efs| d4} | e1 [crc4| fas| cas[crc4] | 2048k | 10m]}}

Example:


Router(config)#network-clock output-source 
system 55 external 0/0/0 t1 efs

Allows transmitting the system clock to external timing output interfaces.

This command provides station clock output as per G.781. We recommend that you use the interface level command instead of global commands. Global command should preferably be used for interfaces that do not have an interface sub mode. For more information on configuring network clock in interface level mode, see Configuring Network Clock in Interface Configuration Mode.

Configuring Network Clock in Interface Configuration Mode

Complete the following steps to configure the network clock in interface configuration mode:

Procedure

  Command or Action Purpose
Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

interface

Example:


Router(config)# interface

Enters interface configuration mode.

Step 4

synchronous mode

Example:


Router(config-if)# synchronous mode

Configures the ethernet interface to synchronous mode.

Note 
This command is applicable to Synchronous Ethernet capable interfaces. The default value is asynchronous mode.
Step 5

network-clock hold-off {0 | 50-10000}

Example:


Router(config-if)# network-clock hold-off 1000

Configures hold-off timer for interface. The default value is 300 milliseconds.

Note 
Displays a warning for values below 300 ms and above 1800 ms.
Step 6

network-clock wait-to-restore 0-86400

Example:


Router(config-if)#network-clock wait-to-restore 1000

Configures the wait-to-restore timer on the SyncE interface.

Caution 

Ensure that you set the wait-to-restore values above 50 seconds to avoid timing flap.

Understanding SSM and ESMC

Network Clocking uses these mechanisms to exchange the quality level of the clock between the network elements:

Synchronization Status Message

Network elements use Synchronization Status Messages (SSM) to inform the neighboring elements about the Quality Level (QL) of the clock. The non-ethernet interfaces such as optical interfaces and SONET/T1/E1 SPA framers use SSM. The key benefits of the SSM functionality are:

  • Prevents timing loops.
  • Provides fast recovery when a part of the network fails.
  • Ensures that a node derives timing from the most reliable clock source.

Ethernet Synchronization Messaging Channel

In order to maintain a logical communication channel in synchronous network connections, ethernet relies on a channel called Ethernet Synchronization Messaging Channel (ESMC) based on IEEE 802.3 Organization Specific Slow Protocol standards. ESMC relays the SSM code that represents the quality level of the Ethernet Equipment Clock (EEC) in a physical layer.

The ESMC packets are received only for those ports configured as clock sources and transmitted on all the SyncE interfaces in the system. The received packets are processed by the clock selection algorithm and are used to select the best clock. The Tx frame is generated based on the QL value of the selected clock source and sent to all the enabled SyncE ports.

Clock Selection Algorithm

Clock selection algorithm selects the best available synchronization source from the nominated sources. The clock selection algorithm has a non-revertive behavior among clock sources with same QL value and always selects the signal with the best QL value. For clock option 1, the default is revertive and for clock option 2, the default is non-revertive.

The clock selection process works in the QL enabled and QL disabled modes. When multiple selection processes are present in a network element, all processes work in the same mode.

QL-enabled mode

In the QL-enabled mode, the following parameters contribute to the selection process:

  • Quality level
  • Signal fail via QL-FAILED
  • Priority
  • External commands.

If no external commands are active, the algorithm selects the reference (for clock selection) with the highest quality level that does not experience a signal fail condition.

If multiple inputs have the same highest quality level, the input with the highest priority is selected.

For multiple inputs having the same highest priority and quality level, the existing reference is maintained (if it belongs to this group), otherwise an arbitrary reference from this group is selected.

QL-disabled mode

In the QL-disabled mode, the following parameters contribute to the selection process:

  • Signal failure
  • Priority
  • External commands

If no external commands are active, the algorithm selects the reference (for clock selection) with the highest priority that does not experience a signal fail condition.

For multiple inputs having the same highest priority, the existing reference is maintained (if it belongs to this group), otherwise an arbitrary reference from this group is selected.

ESMC behavior for Port Channels

ESMC is an Organization Specific Slow Protocol (OSSP) like LACP of port channel, sharing the same slow protocol type, indicating it is in the same sub-layer as LACP. Hence, ESMC works on the link layer on individual physical interfaces without any knowledge of the port channel. This is achieved by setting the egress VLAN as the default VLAN (VLAN 1) and the interface as a physical interface while sending out the packets from the CPU. So none of the service instance, port channel, or VLAN rules apply to the packet passing through the switch ASIC.

ESMC behavior for STP Blocked Ports

ESMC works just above the MAC layer (below spanning tree protocol), and ignores spanning tree Port status. So, ESMC is exchanged even when the port is in the blocked state (but not disabled state). This is achieved by setting the egress VLAN as the default VLAN (VLAN 1) and the interface as a physical interface while sending out packets from the CPU. So none of the service instance, port channel, or VLAN port state, or rules apply to the packet passing through the switch ASIC.

Configuring ESMC in Global Configuration Mode

Complete the following steps to configure ESMC in global configuration mode:

Procedure

  Command or Action Purpose
Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

network-clock synchronization mode ql-enabled

Example:


Router(config)# network-clock synchronization 
mode ql-enabled

Configures the automatic selection process QL-enabled mode.

  • QL is disabled by default.
  • ql-enabled mode can be used only when the synchronization interface is capable to send SSM.
Step 4

esmc process

Example:


Router(config)# esmc process

Enables the ESMC process.

Note 
ESMC can be enabled globally or at the sync-E interface level
Step 5

network-clock quality-level {tx | rx} value {interface interface-name slot/sub-slot/port | external slot/sub-slot/port | gps slot/sub-slot | controller slot/sub-slot/port}

Example:


Router(config)# network-clock quality-level 
rx qL-pRC external 0/0/0 e1 crc4

Forces the QL value for line or external timing output.

Configuring ESMC in Interface Configuration Mode

Complete the following steps to configure ESMC in interface configuration mode:

Procedure

  Command or Action Purpose
Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

interface

Example:


Router(config)# interface

Enters interface configuration mode.

Step 4

esmc mode {tx | rx}

Example:


Router(config-if)# esmc mode tx

Enables the ESMC process at the interface level. The no form of the command disables the ESMC process.

Step 5

network-clock source quality-level value {tx | rx}

Example:


Router(config-if)# network-clock source 
quality-level <value> tx

Configures the QL value for ESMC on a GigabitEthernet port. The value is based on global interworking options:

  • If Option 1 is configured, the available values are QL-PRC, QL-SSU-A, QL-SSU-B, QL-SEC, and QL-DNU.
  • If Option 2 is configured with GEN 2, the available values are QL-PRS, QL-STU, QL-ST2, QL-TNC, QL-ST3, QL-SMC, QL-ST4, and QL-DUS.
  • If Option 2 is configured with GEN1, the available values are QL-PRS, QL-STU, QL-ST2, QL-SMC, QL-ST4, and QL-DUS
Step 6

esmc mode ql-disabled

Example:


Router(config-if)# esmc mode ql-disabled

Enables the QL-disabled mode.

What to do next


Note
By disabling Rx on an interface, any ESMC packet received on the interface shall be discarded. By disabling Tx on an interface, ESMC packets will not be sent on the interface; any pending Switching Message Delay timers (TSM) are also stopped.

Verifying ESMC Configuration

Use the following commands to verify ESMC configuration:

  • show esmc
  • show network-clock synchronization 

Router#show esmc interface gigabitEthernet ?
  <0-1>  GigabitEthernet interface number
Router#show esmc interface gigabitEthernet 0/10
Interface: GigabitEthernet0/10
  Administative configurations:
    Mode: Synchronous
    ESMC TX: Enable
    ESMC RX: Enable
    QL TX: -
    QL RX: -
  Operational status:
    Port status: UP
    QL Receive: QL-SEC
    QL Transmit: QL-DNU
    QL rx overrided: -
    ESMC Information rate: 1 packet/second
    ESMC Expiry: 5 second
Router# show network-clocks synchronization
 
Symbols:     En - Enable, Dis - Disable, Adis - Admin Disable 
             NA - Not Applicable 
             *  - Synchronization source selected 
             #  - Synchronization source force selected 
             &  - Synchronization source manually switched 
Automatic selection process : Enable
Equipment Clock : 2048 (EEC-Option1)
Clock Mode : QL-Disable
ESMC : Disabled
SSM Option : 1 
T0 : GigabitEthernet0/4 
Hold-off (global) : 300 ms
Wait-to-restore (global) : 300 sec
Tsm Delay : 180 ms
Revertive : No
Nominated Interfaces
 Interface            SigType     Mode/QL      Prio  QL_IN  ESMC Tx  ESMC Rx
 Internal             NA          NA/Dis       251   QL-SEC    NA        NA       
 To0/12               NA          NA/En        1     QL-FAILED NA        NA       
 External 0/0/0       10M         NA/Dis       2     QL-FAILED NA        NA       
 Gi0/1                NA          Sync/En      20    QL-FAILED -         -        
*Gi0/4                NA          Sync/En      21    QL-DNU    -         -        
T4 Out
 External Interface   SigType     Input         Prio  Squelch  AIS
 External 0/0/0       E1 CRC4     Internal      1     FALSE    FALSE

Managing Synchronization

You can manage the synchronization using the following management commands:

Command

Purpose

network-clock switch force {interface interface_name slot/port | external slot/card/port}

Router(config)# network-clock switch force interface GigabitEthernet 0/1 t1

Forcefully selects a synchronization source irrespective of whether the source is available and is within the range.

network-clock switch manual {interface interface_name slot/port | external slot/card/port} 


Router(config)# network-clock switch manual interface GigabitEthernet 0/1 t1

Manually selects a synchronization source, provided the source is available and is within the range.

network-clock clear switch {t0 | external slot/card/port [10m | 2m]} 


Router(config)# network-clock clear switch t0

Clears the forced switch and manual switch commands.

Synchronization Example

Configuration for QL-disabled mode clock selection 


network-clock synchronization automatic
network-clock input-source 1 interface ToP0/12
network-clock input-source 2 External 0/0/0 10m
network-clock input-source 20 interface GigabitEthernet0/1
network-clock input-source 21 interface GigabitEthernet0/4
network-clock output-source system 1 External 0/0/0 e1 crc4
!
interface GigabitEthernet0/1
 synchronous mode
 synce state slave
!
interface GigabitEthernet0/4
 negotiation auto
 synchronous mode
 synce state slave
end

GPS Configuration 


10MHz signal
network-clock input-source 1 External 0/0/0 10m
2M signal
network-clock input-source 1 External 0/0/0 2048K

Configuring Synchronous Ethernet for Copper Ports

You can configure synchronization on the copper ports using the following commands:

Command

Purpose 


Router(config-if)# synce state slave

Configures synchronous ethernet copper port as subordinate. 


Router(config-if)# synce state master

Configures synchronous ethernet copper port as primary.


Note
Synchronization on the ethernet copper port is not supported for 10 Mbps speed.

Verifying the Synchronous Ethernet configuration

Use the show network-clock synchronization command to display the sample output. 


Router# show network-clocks synchronization
 
Symbols:     En - Enable, Dis - Disable, Adis - Admin Disable 
             NA - Not Applicable 
             *  - Synchronization source selected 
             #  - Synchronization source force selected 
             &  - Synchronization source manually switched 
Automatic selection process : Enable
Equipment Clock : 2048 (EEC-Option1)
Clock Mode : QL-Disable
ESMC : Disabled
SSM Option : 1 
T0 : GigabitEthernet0/4 
Hold-off (global) : 300 ms
Wait-to-restore (global) : 300 sec
Tsm Delay : 180 ms
Revertive : No
Nominated Interfaces
 Interface            SigType     Mode/QL      Prio  QL_IN  ESMC Tx  ESMC Rx
 Internal             NA          NA/Dis       251   QL-SEC    NA        NA       
 To0/12               NA          NA/En        1     QL-FAILED NA        NA       
 External 0/0/0       10M         NA/Dis       2     QL-FAILED NA        NA       
 Gi0/1                NA          Sync/En      20    QL-FAILED -         -        
*Gi0/4                NA          Sync/En      21    QL-DNU    -         -        
T4 Out
 External Interface   SigType     Input         Prio  Squelch  AIS
 External 0/0/0       E1 CRC4     Internal      1     FALSE    FALSE

Use the show network-clock synchronization detail command to display all details of network-clock synchronization parameters at the global and interface levels. 


Router# show network-clocks synchronization detail 
Symbols:     En - Enable, Dis - Disable, Adis - Admin Disable
             NA - Not Applicable
             *  - Synchronization source selected
             #  - Synchronization source force selected
             &  - Synchronization source manually switched
Automatic selection process : Enable
Equipment Clock : 2048 (EEC-Option1)
Clock Mode : QL-Disable
ESMC : Disabled
SSM Option : 1
T0 : External 0/0/0 10m
Hold-off (global) : 300 ms
Wait-to-restore (global) : 0 sec
Tsm Delay : 180 ms
Revertive : Yes
Force Switch: FALSE
Manual Switch: FALSE
Number of synchronization sources: 3
sm(netsync NETCLK_QL_DISABLE), running yes, state 2A
Last transition recorded: (begin)-> 2A (sf_change)-> 2A
Nominated Interfaces
Interface            SigType     Mode/QL      Prio  QL_IN  ESMC Tx  ESMC Rx
Internal             NA          NA/Dis       251   QL-SEC    NA        NA
To0/12               NA          NA/En        3     QL-SEC    NA        NA
*External 0/0/0       10M         NA/Dis       1     QL-SEC    NA        NA
Gi0/11               NA          Sync/En      2     QL-DNU    -         -
T4 Out
External Interface   SigType     Input         Prio  Squelch  AIS
External 0/0/0       E1 CRC4     Internal      1     FALSE    FALSE
Interface:
---------------------------------------------
Local Interface: Internal
Signal Type: NA
Mode: NA(Ql-disabled)
SSM Tx: DISABLED
SSM Rx: DISABLED
Priority: 251
QL Receive: QL-SEC
QL Receive Configured: -
QL Receive Overrided: -
QL Transmit: -
QL Transmit Configured: -
Hold-off: 0
Wait-to-restore: 0
Lock Out: FALSE
Signal Fail: FALSE
Alarms: FALSE
Slot Disabled: FALSE
SNMP input source index: 1
SNMP parent list index: 0
Local Interface: To0/12
Signal Type: NA
Mode: NA(Ql-disabled)
SSM Tx: DISABLED
SSM Rx: ENABLED
Priority: 3
QL Receive: QL-SEC
QL Receive Configured: -
QL Receive Overrided: -
QL Transmit: -
QL Transmit Configured: -
Hold-off: 300
Wait-to-restore: 0
Lock Out: FALSE
Signal Fail: FALSE
Alarms: FALSE
Slot Disabled: FALSE
SNMP input source index: 2
SNMP parent list index: 0
Local Interface: External 0/0/0
Signal Type: 10M
Mode: NA(Ql-disabled)
SSM Tx: DISABLED
SSM Rx: DISABLED
Priority: 1
QL Receive: QL-SEC
QL Receive Configured: -
QL Receive Overrided: -
QL Transmit: -
QL Transmit Configured: -
Hold-off: 300
Wait-to-restore: 0
Lock Out: FALSE
Signal Fail: FALSE
Alarms: FALSE
Active Alarms :  None
Slot Disabled: FALSE
SNMP input source index: 3
SNMP parent list index: 0
Local Interface: Gi0/11
Signal Type: NA
Mode: Synchronous(Ql-disabled)
ESMC Tx: ENABLED
ESMC Rx: ENABLED
Priority: 2
QL Receive: QL-DNU
QL Receive Configured: -
QL Receive Overrided: -
QL Transmit: -
QL Transmit Configured: -
Hold-off: 300
Wait-to-restore: 0
Lock Out: FALSE
Signal Fail: FALSE
Alarms: FALSE  None
Slot Disabled: FALSE
SNMP input source index: 4
SNMP parent list index: 0
External 0/0/0 e1 crc4's Input:
Internal
  Local Interface: Internal
  Signal Type: NA
  Mode: NA(Ql-disabled)
  SSM Tx: DISABLED
  SSM Rx: DISABLED
  Priority: 1
  QL Receive: QL-SEC
  QL Receive Configured: -
  QL Receive Overrided: -
  QL Transmit: -
  QL Transmit Configured: -
  Hold-off: 300
  Wait-to-restore: 0
  Lock Out: FALSE
  Signal Fail: FALSE
  Alarms: FALSE
  Slot Disabled: FALSE
  SNMP input source index: 1
  SNMP parent list index: 1

Troubleshooting Tips


Note
Before you troubleshoot, ensure that all the network clock synchronization configurations are complete.

The following table provides the troubleshooting scenarios encountered while configuring the synchronous ethernet.

Table 1. Troubleshooting Scenarios for Synchronous Ethernet Configuration

Problem

Solution

Clock selection

  • Verify that there are no alarms on the interfaces. Use the show network-clock synchronization detail RP command to confirm.
  • Use the show network-clock synchronization command to confirm if the system is in revertive mode or non-revertive mode and verify the non-revertive configurations as shown in the following example: 

Router# show network-clocks synchronization

Symbols: En - Enable, Dis - Disable, Adis - Admin Disable
NA - Not Applicable
* - Synchronization source selected
# - Synchronization source force selected
& - Synchronization source manually switched
Automatic selection process : Enable
Equipment Clock : 2048 (EEC-Option1)
Clock Mode : QL-Disable
ESMC : Disabled
SSM Option : 1
T0 : GigabitEthernet0/4
Hold-off (global) : 300 ms
Wait-to-restore (global) : 300 sec
Tsm Delay : 180 ms
Revertive : Yes<<<<If it is non revertive then it will show NO here.
Note 
The above example does not show the complete command output. For complete command output, see the example in Verifying the Synchronous Ethernet configuration.

Reproduce the current issue and collect the logs using the debug network-clock errors , debug network-clock event , and debug network-clock sm RP commands.

Note 
We suggest you do not use these debug commands without TAC supervision. Contact Cisco technical support if the issue persists.

Incorrect quality level (QL) values when you use the show network-clock synchronization detail command.

Use thenetwork clock synchronization SSM[ option 1 | option 2] command to confirm that there is no framing mismatch.

Use the show run interface [ option 1 | option 2] command to validate the framing for a specific interface. For the SSM option 1 framing should be an E1 and for SSM option 2, it should be a T1.

Error message %NETCLK-6-SRC_UPD: Synchronization source 10m 0/0/0 status (Critical Alarms(OOR)) is posted to all selection process is displayed.

Interfaces with alarms or OOR cannot be the part of selection process even if it has higher quality level or priority. OOR should be cleared manually. OOR can be cleared by clear platform timing oor-alarms command.

Troubleshooting ESMC Configuration

Use the following debug commands to troubleshoot the PTP configuration on the Cisco ASR 901 router:


DANGER

We suggest you do not use these debug commands without TAC supervision.

Command

Purpose 

debug esmc error 
debug esmc event 
debug esmc packet [interface interface-name>] 
debug esmc packet rx [interface interface-name] 
debug esmc packet tx [interface interface-name]

Verify whether the ESMC packets are transmitted and received with proper quality-level values.

Configuring PTP for the Cisco ASR 901 Router

Effective from Cisco IOS Release 15.4 (3) S, the Cisco ASR 901 Router supports PTP over Ethernet.


Note
Before configuring PTP, you should set the system time to the current time. See Setting System Time to Current Time section for configuration details.

This section contains the following topics:

Restrictions

  • In IP mode only unicast static and unicast negotiation modes are supported. Multicast mode is not supported.
  • PTP over Ethernet is supported only in multicast mode.
  • PTP over Ethernet is not supported in telecom profiles.
  • PTP subordinate supports both single and two-step modes. PTP primary supports only two-step mode.
  • VLAN 4093 and 4094 are used for internal PTP communication; do not use VLAN 4093 and 4094 in your network.
  • VLAN 4094 is used for internal PTP communication; do not use VLAN 4094 in your network.

    Note

    Effective from Cisco IOS Release 15.4 (3) S, VLAN 4093 is not reserved for internal communication. However, every clock-port created picks a VLAN from the free pool list and reserves it internally for PTP usage only.

  • Effective from Cisco IOS Release 15.5 (2)S, SVI interface is supported. With this, you can use SVI or Loopback interface in Cisco ASR 901 router instead of ToP interface for configuring 1588 interface/IP address.

  • The 1pps output command is not supported on primary ordinary clock.

  • Sync and Delay request rates should be above 32 pps. The optimum value is 64 pps.
  • Clock-ports start as primary even when they are configured as subordinate-only. The initial or reset state of the clock is primary. Therefore, the primary clock must have higher priority (priority1, priority2) for the subordinate to accept the primary.

  • IEEEv2BMCA is supported only in unicast negotiation mode.

  • IEEEv2BMCA is not supported in multicast and unicast modes.

  • You should use no transport ipv4 unicast command to remove an existing transport configuration before changing the transport configuration from Loopback to VLAN and vice versa.

  • You should use no transport ipv4 unicast command when there is change in the IP address of the interface on which PTP primary is configured.

  • Effective from Cisco IOS Release 15.4 (3) S, VLAN id is reserved for each of the clock-port being configured. Therefore, depending on number of clock-ports, maximum of 20 VLANs can get reserved for internal purpose on Boundary Clock. For finding an internal VLAN for clock-port over PTP configuration, a free VLAN id is searched from 4093 in decreasing order. The free VLAN id remains reserved as long as the corresponding clocking-port is configured and this VLAN id cannot be used for any other purpose.


Note

  • You should not use VLAN 4094 on your network as Vlan 4094 is reserved internally to process PTP management packets.

  • The 1pps port is enabled by default to receive output signal.

Precision Time Protocol

The Cisco ASR 901 Router supports the Precision Time Protocol (PTP) as defined by the IEEE 1588-2008 standard. PTP provides accurate time synchronization over packet-switched networks.

The following table provides the description of the nodes within a PTP network.

Network Element

Description

Grandmaster

A network device physically attached to the primary time source. All clocks are synchronized to the grandmaster clock.

Ordinary Clock

An ordinary clock is a 1588 clock with a single PTP port that can operate in one of the following modes:

  • Primary mode—Distributes timing information over the network to one or more subordinate clocks, thus allowing the subordinate to synchronize its clock to the primary.

  • Subordinate mode—Synchronizes its clock to a primary clock. You can enable the subordinate mode on up to two interfaces simultaneously in order to connect to two different primary clocks.

Boundary Clock

The device participates in selecting the best primary clock and can act as the primary clock if no better clocks are detected.

Boundary clock starts its own PTP session with a number of downstream slaves. The boundary clock mitigates the number of network hops and results in packet delay variations in the packet network between the Grand Master and subordinate.

Transparent Clock

A transparent clock is a device or a switch that calculates the time it requires to forward traffic and updates the PTP time correction field to account for the delay, making the device transparent in terms of time calculations.

IEEEV2 Best Master Clock Algorithm Overview

1588-2008 is an IEEE standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems. Effective from Cisco IOS Release 15.4(3)S, the Cisco ASR 901 Router supports IEEEV2 Best Master Clock Algorithm (BMCA).

Information About Best Master Clock Algorithm

BMCA is used to select the master clock on each link, and ultimately, select the grandmaster clock for the entire Precision Time Protocol (PTP) domain. BCMA runs locally on each port of the ordinary and boundary clocks, and selects the best clock on the link by comparing the local data sets with the received data from the announce messages. BMCA also runs the state decision algorithm to determine the PTP port states.

The best master clock is selected based on the following parameters:

  • Priority1—User-configurable value ranging from 0 to 255; lower value takes precedence

  • ClockClass—Defines the traceability of time or frequency from the grandmaster clock

  • ClockAccuracy—Defines the accuracy of a clock; lower value takes precedence

  • OffsetScaledLogVariance—Defines the stability of a clock

  • Priority2—User-configurable value ranging from 0 to 255; lower value takes precedence

  • ClockIdentity—8-byte number, typically in IEEE-EUI64 format, to uniquely identify a clock

By changing the user-configurable values, network administrators can influence the way the grandmaster clock is selected. BMCA provides the mechanism that allows all PTP clocks to dynamically select the best master clock (grandmaster) in an administration-free, fault-tolerant way, especially when the grandmaster clocks changes.

The following figure shows a sample IEEEV2 BMCA topology.
Figure 1. Sample IEEEV2 BMCA Topology


The Cisco ASR 901 Router supports IEEEv2 BMCA in following scenarios:

  • IEEEv2BMCA with Slave Ordinary Clock

  • IEEEv2BMCA with Hybrid Ordinary Clock

  • IEEEv2BMCA with Boundary Clock

  • IEEEv2BMCA with Hybrid Boundary clock

For more information on configuring the BMCA in ordinary and boundary clocks, see Configuring PTP Ordinary Clock and PTP Boundary Clock.

Setting System Time to Current Time

To set the system time to the current time before configuring PTP, complete the steps given below:

Command

Purpose

Router# calendar set hh : mm : ss day month year

Router# calendar set 09:00:00 6 Feb 2013

Sets the hardware clock.

  • hh : mm : ss—RCurrent time in hours (using 24-hour notation), minutes, and seconds.
  • day—Current day (by date) in the month.
  • month—Current month (by name).
  • year—Current year (no abbreviation).

Router# clock read-calendar

Synchronizes the system clock with the calendar time.

Router# show clock

Verifies the clock setting.

Configuring PTP Ordinary Clock

The following sections describe how to configure a PTP ordinary clock.

Configuring Primary Ordinary Clock

Complete the following steps to configure the a primary ordinary clock:

Procedure
  Command or Action Purpose
Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

ptp clock ordinary domain domain

Example:

Router(config)# ptp clock ordinary domain 0

Configures the PTP clock as an ordinary clock and enters clock configuration mode.

  • domain —The PTP clocking domain number. The range is from 0 to 127.
Step 4

priority1 priority-value

Example:

Router(config-ptp-clk)# priority1 4

(Optional) Sets the preference level for a clock.

  • priority-value —The range is from 0 to 255. The default is 128.
Step 5

priority2 priority-value

Example:

Router(config-ptp-clk)# priority2 8

(Optional) Sets a secondary preference level for a clock. The priority2 value is considered only when the router is unable to use priority1 and other clock attributes to select a clock.

  • priority-value —The range is from 0 to 255. The default is 128.
Step 6

clock-port port-name master

Example:

Router(config-ptp-clk)# clock-port primary master

Sets the clock port to PTP primary and enters clock port configuration mode. In primary mode, the port exchanges timing packets with PTP subordinate devices.

Step 7

Do one of the following:

  • transport ipv4 unicast interface interface-type interface-number
  • transport ethernet multicast bridge-domain bridge-id
Example:
Router(config-ptp-port)# transport ipv4 
unicast interface loopback 0

Specifies the transport mechanism for clocking traffic; you can use IPv4 or Ethernet transport.

  • interface-type —The type of the interface.
  • interface-number —The number of the interface.

Configures a bridge domain.

  • bridge-id —Identifier for the bridge domain instance. The range is from 1 to 4094.
Note 

Effective with Cisco IOS Release 15.5(2)S onwards, VLAN interface (with DHCP assigned IP or static IP) is supported. The option of using dynamic IP for PTP over VLAN is generally meant for a subordinate interface. Though the implementation supports dynamic IP assignment on the PTP primary, you must configure the dynamically assigned IP in “clock source ” command on the PTP subordinate.

Step 8

clock-destination clock-ip-address

Example:

Router(config-ptp-port)# clock-destination 8.8.8.1

Specifies the IP address of a clock destination when the router is in PTP primary mode.

Step 9

sync interval interval

Example:

Router(config-ptp-port)# sync interval -5

(Optional) Specifies the interval used to send PTP synchronization messages. The intervals are set using log base 2 values. The Cisco ASR 901 router supports the following values:

  • -5—1 packet every 1/32 seconds, or 32 packets per second.
  • -6—1 packet every 1/64 seconds, or 64 packets per second.

The default is -6.

Step 10

announce interval interval

Example:

Router(config-ptp-port)# announce interval 2

(Optional) Specifies the interval for PTP announce messages. The intervals are set using log base 2 values, as follows:

  • 4—1 packet every 16 seconds.
  • 3—1 packet every 8 seconds.
  • 2—1 packet every 4 seconds.
  • 1—1 packet every 2 seconds.
  • 0—1 packet every second (default).
Step 11

end

Example:

Router(config-ptp-port)# end

Exits clock port configuration mode and enters privileged EXEC mode.

Configuring Subordinate Ordinary Clock

Complete the following steps to configure a subordinate ordinary clock:


Note
PTP redundancy is an implementation on different clock nodes by which the PTP subordinate clock node interacts with multiple primary ports such as grand master, boundary clock nodes, and so on. A new servo mode is defined under PTP to support high PDV scenarios (when the PDVs exceed G.8261 standard profiles). You should use the servo mode high-jitter command to enable this mode on the PTP subordinate. In servo mode, convergence time would be longer than usual, as this mode is meant only for frequency synchronization.
Procedure
  Command or Action Purpose
Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

ptp clock ordinary domain domain

Example:

Router(config)# ptp clock ordinary domain 0

Configures the PTP clock as an ordinary clock and enters clock configuration mode.

Step 4

clock-port port-name slave

Example:

Router(config-ptp-clk)# clock-port subordinate slave

Sets the clock port to PTP subordinate mode and enters clock port configuration mode. In subordinate mode, the port exchanges timing packets with a PTP primary clock.

Step 5

  • transport ipv4 unicast interface interface-type interface-number or
  • transport ethernet multicast bridge-domain bridge-id
Example:
Router(config-ptp-port)# transport ipv4 unicast interface loopback 0

Specifies the transport mechanism for clocking traffic; you can use IPv4 or Ethernet transport.

  • interface-type —Type of the interface, for example, loopback.
  • interface-number —Number of the interface. Values range from 0 to 2,14,74,83,647.

Configures a bridge domain.

  • bridge-id —Identifier for the bridge domain instance. The range is from 1 to 4094.
Note 

Effective with Cisco IOS Release 15.5(2)S, VLAN interface (with DHCP assigned IP or static IP) is also supported.

Step 6

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 5.5.5.5

Specifies the address of a PTP primary clock. You can specify a priority value as follows:

  • No priority value—Assigns a priority value of 0, the highest priority.
  • 1—Assigns a priority value of 1.
  • 2—Assigns a priority value of 2.
  • 3—Assigns a priority value of 3.

Repeat this step for each additional primary clock. You can configure up to four primary clocks.

Note 

Priority is used as an index for the configured clock sources and is not a criteria for the BMCA.

Step 7

clock source source-address

Example:

Router(config-ptp-port)# clock source 8.8.8.1

Specifies the address of a PTP primary clock.

Step 8

announce timeout value

Example:

Router(config-ptp-port)# announce timeout 8

(Optional) Specifies the number of PTP announcement intervals before the session times out.

  • value —The range is from 1 to 10. The default is 3.
Step 9

delay-req interval interval

Example:

Router(config-ptp-port)# delay-req interval 1

(Optional) Configures the minimum interval allowed between PTP delay request messages.

The intervals are set using log base 2 values, as follows:

  • 5—1 packet every 32 seconds
  • 4—1 packet every 16 seconds
  • 3—1 packet every 8 seconds
  • 2—1 packet every 4 seconds
  • 1—1 packet every 2 seconds
  • 0—1 packet every second
  • -1—1 packet every 1/2 second, or 2 packets per second
  • -2—1 packet every 1/4 second, or 4 packets per second
  • -3—1 packet every 1/8 second, or 8 packets per second
  • -4—1 packet every 1/16 seconds, or 16 packets per second.
  • -5—1 packet every 1/32 seconds, or 32 packets per second.
  • -6—1 packet every 1/64 seconds, or 64 packets per second.
  • -7—1 packet every 1/128 seconds, or 128 packets per second.

The default is -6.

Step 10

sync interval interval

Example:

Router(config-ptp-port)# sync interval -5

(Optional) Specifies the interval used to send PTP synchronization messages. The intervals are set using log base 2 values. The Cisco ASR 901 router supports the following values:

  • -5—1 packet every 1/32 seconds, or 32 packets per second.
  • -6—1 packet every 1/64 seconds, or 64 packets per second.

The default is -6.

Step 11

end

Example:

Router(config-ptp-port)# end

Exits clock port configuration mode and enters privileged EXEC mode.

Configuring PTP in Unicast Mode

In unicast mode, the subordinate port and the primary port need to know each other’s IP address. Unicast mode has one to one mapping between the subordinate and the primary. One primary can have just one subordinate and vice-versa. Unicast mode is not a good option for scalability.

The command used for configuring Cisco ASR 901 on unicast mode is clock-port.

Command

Purpose

Router(config-ptp-clk)# clock-port

Configures Cisco ASR 901 on unicast mode. The following options can be configured with this command:

  • Port Name
  • Port Role

Before configuring Cisco ASR 901 on different modes, you need to configure the loopback address. The following example shows the configuration of loopback address:


Note
This loopback address cannot be used for any protocol other than PTP. If a VLAN interface is used instead of loopback, the Vlan IP can be used by other protocols. It does not become dedicated to PTP. 

Router(config)#int loopback
Router(config-if)#ip address 8.8.8.2 255.255.255.255
Router(config-if)#
no sh
 
Router#sh run int loopback
Building configuration...
 
Current configuration : 72 bytes
!
interface loopback
 ip address 8.8.8.2 255.255.255.255
 end
!

Note
Ensure that this loopback interface is reachable (using ICMP ping) from remote locations, before assigning the interface to PTP. Once the interface is assigned to PTP, it does not respond to ICMP pings. However, If PTP is configured over VLAN, the interface responds to ICMP ping even after it is assigned to PTP.

The following example shows the configuration of Cisco ASR 901 on the unicast mode: 


Router# configure terminal
Router(config)# ptp clock ordinary domain 0
 
Router(config-ptp-clk) clock-port SUBORDINATE slave
Router(config-ptp-port)# transport ipv4 unicast interface loopback 10
Router(config-ptp-port)# clock-source 8.8.8.1

Configuring PTP in Unicast Negotiation Mode

In unicast negotiation mode, primary port does not know the subordinate port at the outset. Subordinate port sends negotiation TLV when active and primary port figures out that there is some subordinate port for synchronization. Unicast negotiation mode is a good option for scalability as one primary has multiple slaves.

The command used for configuring Cisco ASR 901 router on unicast negotiation mode is clock-port.

Command

Purpose

Router(config-ptp-clk)# clock-port

Configures Cisco ASR 901 router on unicast negotiation mode. The following options can be configured with this command:

  • Port Name
  • Port Role

The following example shows the configuration of Cisco ASR 901 router on the unicast negotiation mode: 


Router# configure terminal
Router(config)# ptp clock ordinary domain 0 
Router(config-ptp-clk) clock-port SUBORDINATE slave 
Router(config-ptp-port)# transport ipv4 unicast interface loopback 23 negotiation
Router(config-ptp-port)# clock-source 8.8.8.1  
  
Router(config)# ptp clock ordinary domain 0 
Router(config-ptp-clk)# clock-port PRIMARY Master
Router(config-ptp-port)# transport ipv4 unicast interface loopback 23 negotiation
Router(config-ptp-port)# sync interval  <>
Router (config-ptp-port)# announce interval <>

Configuring PTP in Multicast Mode

PTP over Ethernet uses multicast MAC addresses for communication of PTP messages between the subordinate clock and the primary clock. The primary sends the announce, synchronization, and delay-response packets using the multicast method. The PTP subordinate receives the multicast announce packets from the primary or multiple primary clocks and determines the best primary one using Best Master Clock Algorithm (BMCA). The subordinate receives and processes the synchronization from the selected primary clock in the same bridge domain.

You should configure the transit nodes as boundary clocks so that the primary and the subordinate clocks can be operated in different bridge domains. This will control the multicast traffic on the network. The following topology is used for configuring PTP in multicast mode.

Figure 2. PTP Topology in Multicast Mode


Before configuring Cisco ASR 901 Router on different modes, you need to configure the bridge domain. The following example shows the configuration of bridge domain and the PTP topology in multicast mode:

Figure 3. Example for PTP Topology in Multicast Mode 



 
RouterA #show run interface gigabitethernet0/3

Building configuration...
Current configuration : 202 bytes
!
interface GigabitEthernet0/3
 no ip address
 negotiation auto
 service instance 1 ethernet
  encapsulation dot1q 100 
  rewrite ingress tag pop 1 symmetric
  bridge-domain 999
 !901
end

RouterA# configure terminal
RouterA(config)# ptp clock ordinary domain 0
RouterA(config-ptp-clk)# clock-port PRIMARY master 
RouterA(config-ptp-port)# transport ethernet multicast bridge-domain 999

RouterB# show run interface gigabitethernet0/3
 
Building configuration...
Current configuration : 202 bytes
!
interface GigabitEthernet0/3
 no ip address
 negotiation auto
 service instance 1 ethernet
  encapsulation dot1q 100
  rewrite ingress tag pop 1 symmetric
  bridge-domain 999
! end

RouterB# configure terminal
RouterB(config)# ptp clock ordinary domain 0
RouterB(config-ptp-clk)# clock-port SUBORDINATE slave
RouterB(config-ptp-port)# transport ethernet multicast bridge-domain 999

Note
For PTP over Ethernet support on Cisco ASR 901 Router, the PTP packets received from an external interface should be single tagged with pop1 and double tagged with pop2. Also, the external interface on which the PTP packets are received should have one of the following configurations on EVC.

No pop

pop 1

pop 2

Untag

Yes

—

—

Dot1q

—

Yes

—

QinQ

—

—

Yes

Dot1ad

—

Yes

—

Dot1ad-dot1ad

—

—

Yes

Default

—

—

—

Priority

—

Yes

—

PTP Boundary Clock

A PTP boundary clock (BC) acts as a middle hop between a PTP primary and PTP subordinate. It has multiple ports which can act as a primary or subordinate port as shown in PTP Boundary Clock. A PTP boundary clock has one subordinate port and one or more primary ports. A subordinate port acts as a subordinate to a remote PTP primary, while a primary port acts as a primary to a remote PTP subordinate. A PTP boundary clock derives clock from a primary/grand master clock (by acting as a subordinate) and sends the derived clock to the slaves connected to it (by acting as a primary).

PTP boundary clock starts its own PTP session with a number of downstream slaves. The PTP boundary clock mitigates the number of network hops and results in packet delay variations in the packet network between the grand master and subordinate.

Figure 4. PTP Boundary Clock

The Cisco ASR 901 PTP boundary clock has the following capabilities:

  • Support for up to 20 clock ports.
  • Simultaneous support for static and negotiated clock ports.
  • Support for up to 36 slaves and 1 primary.

Note
If all clock ports created in PTP boundary clock are static, Cisco ASR 901 supports only 1 primary port and 19 subordinate ports. However, if one or more subordinate ports are configured in unicast negotiation mode, Cisco ASR 901 can support up to 36 subordinates.
  • Support for dynamic addition and deletion of clock ports. This capability is supported only on boundary clock primary ports.
  • Support for selecting boundary clock as the clock source.

Configuring PTP Boundary Clock

Complete the following steps to configure the PTP boundary clock.

Before you begin

Note
If PTP boundary clock is configured before installing the 1588BC license, remove the boundary clock configuration and reconfigure the boundary clock after the license installation.

Note
  • The loopback address configured for PTP port can be used only for PTP functionality. This restriction applies only for PTP over loopback. VLAN IP can be used by other protocols.
  • The loopback address configured for PTP port does not respond to pings. However, VLAN address (if configured for PTP) will respond to pings.
  • A clock port once configured as primary cannot change to subordinate dynamically, and vice versa.
  • PTP boundary clock can be configured for only one domain.
Procedure
  Command or Action Purpose
Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

ptp clock boundary domain domain

Example:

Router(config)# ptp clock boundary domain 0

Configures the PTP boundary clock and selects the best primary clock. It also acts as the primary clock if no better clocks are detected. Enters clock configuration mode.

  • domain —The PTP clocking domain number. Valid values are from 0 to 127.
Step 4

clock-port port-name slave

Example:

Router(config-ptp-clk)# clock-port SUBORDINATE slave

Sets the clock port to PTP subordinate mode and enters the clock port configuration mode. In subordinate mode, the port exchanges timing packets with a PTP primary clock.

Step 5

Do one of the following:

  • transport ipv4 unicast interface interface-type interface-number [negotiation]
  • transport ethernet multicast bridge-domain bridge-id
Example:
Router(config-ptp-port)# transport ipv4 unicast 
interface loopback 0 negotiation

Specifies the transport mechanism for clocking traffic; you can use IPv4 or Ethernet transport.

  • interface-type —The type of the interface.
  • interface-number —The number of the interface.
  • negotiation —(Optional) Enables dynamic discovery of subordinate devices and their preferred format for sync interval and announce interval messages.

Configures a bridge domain.

  • bridge-id —Identifier for the bridge domain instance. The range is from 1 to 4094.
Note 

Effective with Cisco IOS Release 15.5(2)S onwards, VLAN interface (with DHCP assigned IP or static IP) is supported.

Step 6

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 5.5.5.5

Specifies the address of a PTP primary clock. You can specify a priority value as follows:

  • No priority value—Assigns a priority value of 0, the highest priority.
  • 1—Assigns a priority value of 1.
  • 2—Assigns a priority value of 2.
  • 3—Assigns a priority value of 3.
Note 

Priority is used as an index for the configured clock sources and is not a criteria for the BMCA.

Step 7

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 30.30.30.30 1

Specifies the address of an additional PTP primary clock; repeat this step for each additional primary clock. You can configure up to four primary clocks.

Step 8

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 2.2.2.2 2

Specifies the address of an additional PTP primary clock; repeat this step for each additional primary clock. You can configure up to four primary clocks.

Step 9

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 50.50.50.50 3

Specifies the address of an additional PTP primary clock; repeat this step for each additional primary clock. You can configure up to four primary clocks.

Step 10

clock source source-address

Example:

Router(config-ptp-port)# clock source 133.133.133.133

Specifies the address of a PTP primary clock.

Step 11

clock-port port-name master

Example:

Router(config-ptp-port)# clock-port PRIMARY master

Sets the clock port to PTP primary mode. In primary mode, the port exchanges timing packets with PTP subordinate devices.

Note 
The primary clock-port does not establish a clocking session until the subordinate clock-port is phase aligned.
Step 12

Do one of the following:

  • transport ipv4 unicast interface interface-type interface-number [negotiation]
  • transport ethernet multicast bridge-domain bridge-id
Example:
Router(config-ptp-port)# transport ipv4 unicast 
interface loopback 0 negotiation

Specifies the transport mechanism for clocking traffic; you can use IPv4 or Ethernet transport.

  • interface-type —The type of the interface.
  • interface-number —The number of the interface.
  • negotiation —(Optional) Enables dynamic discovery of subordinate devices and their preferred format for sync interval and announce interval messages.

Configures a bridge domain.

  • bridge-id —Identifier for the bridge domain instance. The range is from 1 to 4094.
Note 

Effective with Cisco IOS Release 15.5(2)S onwards, VLAN interface (with DHCP assigned IP or static IP) is supported. The option of using dynamic IP for PTP over VLAN is generally meant for a subordinate interface. Though the implementation supports dynamic IP assignment on the PTP primary, you must configure the dynamically assigned IP in “clock source ” command on the PTP subordinate.

Step 13

exit

Example:

Router(config-ptp-port)# exit

Exits clock port configuration mode.

Verifying PTP modes

Ordinary Clock

Use the show ptp clock dataset current command to display the sample output. 


Router#show ptp clock dataset current
CLOCK [Ordinary Clock, domain 0]
Steps Removed: 1
Offset From Master: 0

Use the show ptp clock dataset default command to display the sample output. 


Router#show ptp clock dataset default
CLOCK [Ordinary Clock, domain 0]
Two Step Flag: No
Clock Identity: 0x0:A:8B:FF:FF:5C:A:80
Number Of Ports: 1
Priority1: 128
Priority2: 128
Domain Number: 0
Slave Only: Yes
Clock Quality:
Class: 13
Accuracy: Greater than 10s
Offset (log variance): 52592

Use the show ptp clock dataset parent domain command to display the sample output. 


Router# show ptp clock dataset parent domain 0
CLOCK [Ordinary Clock, domain 0]
Parent Stats: No
Observed Parent Offset (log variance): 65535
Observed Parent Clock Phase Change Rate: 0
Grandmaster Clock:
Identity: 0x0:D0:4:FF:FF:B8:6C:0
Priority1: 128
Priority2: 128
Clock Quality:
Class: 13
Accuracy: Within 1s
Offset (log variance): 52592

Use the show ptp clock dataset time-properties domain command to display the sample output. 


Router# show ptp clock dataset time-properties domain 0
CLOCK [Ordinary Clock, domain 0]
Current UTC Offset Valid: TRUE
Current UTC Offset: 33
Leap 59: FALSE
Leap 61: FALSE
Time Traceable: TRUE
Frequency Traceable: TRUE
PTP Timescale: TRUE
Time Source: Internal Oscillator

Boundary Clock

Use the show ptp clock dataset current command to display the sample output. 


Router# show ptp clock dataset current
CLOCK [Boundary Clock, domain 0]
  Steps Removed: 0
  Offset From Master: 0ns

Use the show ptp clock dataset default command to display the sample output. 


Router# show ptp clock dataset default
CLOCK [Boundary Clock, domain 0]
  Two Step Flag: No
  Clock Identity: 0x0:0:0:FF:FE:0:23:45
  Number Of Ports: 1
  Priority1: 128
  Priority2: 128
  Domain Number: 0
  Slave Only: Yes
  Clock Quality:
    Class: 248
    Accuracy: Within 25us
    Offset (log variance): 22272

Use the show ptp clock dataset parent domain command to display the sample output. 


Router# show ptp clock dataset parent domain 0
CLOCK [Boundary Clock, domain 0]
  Parent Stats: No
  Observed Parent Offset (log variance): 0
  Observed Parent Clock Phase Change Rate: 0
  Grandmaster Clock:
    Identity: 0x0:0:0:FF:FE:0:23:45
    Priority1: 128
    Priority2: 128
    Clock Quality:
      Class: 248
      Accuracy: Within 25us
      Offset (log variance): 22272

Use the show ptp clock dataset time-properties domain command to display the sample output. 


Router# show ptp clock dataset time-properties domain 0
CLOCK [Boundary Clock, domain 0]
  Current UTC Offset Valid: FALSE
  Current UTC Offset: 34
  Leap 59: FALSE
  Leap 61: FALSE
  Time Traceable: FALSE
  Frequency Traceable: FALSE
  PTP Timescale: FALSE
  Time Source: Internal Oscillator

Use the show ptp port running detail command to display the details of PTP boundary clock such as primary clock sources added, clock class, and variance. 

Router#show ptp port running detail

PORT [SLAVE] CURRENT PTP MASTER PORT

PORT [SLAVE] PREVIOUS PTP MASTER PORT

PORT [SLAVE] LIST OF PTP MASTER PORTS

LOCAL PRIORITY 1
  Protocol Address: 22.22.22.22
  Clock Identity:  0x40:55:39:FF:FE:89:6F:40
  PTSF Status: 
  Alarm In Stream: 
  Clock Stream Id: 0
  Priority1: 128
  Priority2: 128
  Class: 58
  Accuracy: Within 25us
  Offset (log variance): 22272
  Steps Removed: 0

LOCAL PRIORITY 2
  Protocol Address: 66.66.66.66
  Clock Identity:  0x4C:0:82:FF:FE:C7:6F:1C
  PTSF Status: 
  Alarm In Stream: 
  Clock Stream Id: 0
  Priority1: 128
  Priority2: 128
  Class: 58
  Accuracy: Within 25us
  Offset (log variance): 22272
  Steps Removed: 0

LOCAL PRIORITY 3
  Protocol Address: 77.77.77.77
  Clock Identity:  0x0:0:0:0:0:0:0:0
  PTSF Status: PTSF_SIGNAL_FAIL 
  Alarm In Stream: ALARM_ANNOUNCE_FAIL 
  Clock Stream Id: 0
  Priority1: 0
  Priority2: 0
  Class: 0
  Accuracy: Unknown
  Offset (log variance): 0
  Steps Removed: 0

Use the show ptp clock running domain command to display the sample output. 


Router#show ptp clock running doman 0

                      PTP Boundary Clock [Domain 0]

         State          Ports          Pkts sent      Pkts rcvd     Redundancy Model

         PHASE_ALIGNED  2              324215         1257513       Hot standby

                               PORT SUMMARY
                                                                                    PTP Master
Name               Tx Mode      Role         Transport    State        Sessions     Port Addr

SLAVE              unicast      slave        To3/0/2      -            1            9.9.9.1
MASTER             unicast      master       To3/0/2      -            2

Verifying PTP Configuration on the 1588V2 subordinate in Unicast Mode

The following examples help you verify the PTP configuration on the1588V2 subordinate.


Note
The loopback interface assigned to PTP does not respond to ICMP pings. To check route availability, either do it before assigning the interface to PTP, or remove PTP from the interface and then perform ICMP ping. For removing PTP, useno transport ipv4 unicast interface loopback interface command. For PTP over VLAN, ping will work even when interface is assigned to PTP.

Note
The bridge state indicates the extension of previously known state which can be ignored or considered to be normal. The clock state can get into holdover from bridge state when the packet delay variation is high on the received PTP packets or the PTP connection is lost. This holdover state indicates that the clock cannot be recovered from PTP packets as the quality is poor.

Example 1 


Router# show ptp clock runn dom 0
                      PTP Ordinary Clock [Domain 0]
         State          Ports          Pkts sent      Pkts rcvd      
         ACQUIRING      1              5308           27185     
                               PORT SUMMARY
Name               Tx Mode      Role         Transport    State        Sessions
SUBORDINATE              unicast      slave        Lo10         -            1
                             SESSION INFORMATION
SUBORDINATE [L010] [Sessions 1]
 Peer addr          Pkts in    Pkts out   In Errs    Out Errs  
 3.3.3.3            27185      5308       0          0

Example 2 


Router# show platform ptp state
flag = 2
	 FLL State                     : 2 (Fast Loop)
	 FLL Status Duration           : 7049 (sec)
	 Forward Flow Weight           : 0.0
	 Forward Flow Transient-Free   : 900 (900 sec Window)
	 Forward Flow Transient-Free   : 3600 (3600 sec Window)
	 Forward Flow Transactions Used: 23.0 (%)
	 Forward Flow Oper. Min TDEV   : 4254.0 (nsec)
	 Forward Mafie                 : 38.0
	 Forward Flow Min Cluster Width: 7550.0 (nsec)
	 Forward Flow Mode Width       : 21400.0 (nsec)
	 Reverse Flow Weight           : 100.0
	 Reverse Flow Transient-Free   : 900 (900 sec Window)
	 Reverse Flow Transient-Free   : 3600 (3600 sec Window)
	 Reverse Flow Transactions Used: 200.0 (%)
	 Reverse Flow Oper. Min TDEV   : 487.0 (nsec)
	 Reverse Mafie                 : 36.0
	 Reverse Flow Min Cluster Width: 225.0 (nsec)
	 Reverse Flow Mode Width       : 450.0 (nsec)
	 Frequency Correction          : 257.0 (ppb)
	 Phase Correction              : 0.0 (ppb)
	 Output TDEV Estimate          : 1057.0 (nsec)
	 Output MDEV Estimate          : 1.0 (ppb)
	 Residual Phase Error          : 0.0 (nsec)
	 Min. Roundtrip Delay          : 45.0 (nsec)
	 Sync Packet Rate              : 65 (pkts/sec)
	 Delay Packet Rate             : 65 (pkts/sec)
	 Forward IPDV % Below Threshold: 0.0
	 Forward Maximum IPDV          : 0.0 (usec)
	 Forward Interpacket Jitter    : 0.0 (usec)
	 Reverse IPDV % Below Threshold: 0.0
	 Reverse Maximum IPDV          : 0.0 (usec)
	 Reverse Interpacket Jitter    : 0.0 (usec)

Verifying PTP Configuration on the 1588V2 Subordinate in Multicast Mode

A typical configuration on a 1588V2 subordinate in the multicast mode is:

Note

For a OC-Subordinate configured in PTP over ethernet in the multicast mode, clock source details cannot be specified. The show ptp port running detail command shows all the four primary clock details. However, the details of those primary clocks that are having a session with the subordinate clock will be constantly updated. In the following example two OC-PRIMARY clocks are having session with a OC-SUBORDINATE. 


Router# show run | sec ptp
ptp clock ordinary domain 0
 1pps-out 0 1 ns
 clock-port SUBORDINATE slave
  transport ethernet multicast bridge-domain 77 

Router# show ptp port running detail 

PORT [SUBORDINATE] CURRENT PTP PRIMARY PORT
  Protocol Address: 4055.3989.728b
  Clock Identity: 0x40:55:39:FF:FE:89:72:88

PORT [SUBORDINATE] PREVIOUS PTP PRIMARY PORT
  Protocol Address: 0000.0000.0000
  Clock Identity: 0x0:0:0:0:0:0:0:0
  Reason: 

PORT [SUBORDINATE] LIST OF PTP PRIMARY PORTS

LOCAL PRIORITY 0
  Protocol Address: 4055.3989.78a3
  Clock Identity:  0x40:55:39:FF:FE:89:78:A0
  PTSF Status: 
  Alarm In Stream: 
  Clock Stream Id: 0
  Priority1: 128
  Priority2: 128
  Class: 248
  Accuracy: Within 25us
  Offset (log variance): 22272
  Steps Removed: 0

LOCAL PRIORITY 1
  Protocol Address: 4055.3989.728b
  Clock Identity:  0x40:55:39:FF:FE:89:72:88
  PTSF Status: 
  Alarm In Stream: 
  Clock Stream Id: 0
  Priority1: 128
  Priority2: 128
  Class: 58
  Accuracy: Within 25us
  Offset (log variance): 22272
  Steps Removed: 0

LOCAL PRIORITY 2
  Protocol Address: UNKNOWN
  Clock Identity:  0x0:0:0:0:0:0:0:0
  PTSF Status: 
  Alarm In Stream: 
  Clock Stream Id: 0
  Priority1: 0
  Priority2: 0
  Class: 0
  Accuracy: Unknown
  Offset (log variance): 0
  Steps Removed: 0

LOCAL PRIORITY 3
  Protocol Address: UNKNOWN
  Clock Identity:  0x0:0:0:0:0:0:0:0
  PTSF Status: 
  Alarm In Stream: 
  Clock Stream Id: 0
  Priority1: 0
  Priority2: 0
  Class: 0
  Accuracy: Unknown
  Offset (log variance): 0
  Steps Removed: 0


Router# show run int gigabitEthernet 0/0
Building configuration...

Current configuration : 183 bytes
!
interface GigabitEthernet0/0
 no ip address
 negotiation auto
 service instance 1 ethernet
  encapsulation dot1q 33
  rewrite ingress tag pop 1 symmetric
  bridge-domain 77
 !
end

Router# show run int gigabitEthernet 0/3
Building configuration...

Current configuration : 297 bytes
!
interface GigabitEthernet0/3
 no ip address
 negotiation auto
 synchronous mode
 synce state slave
 service instance 2 ethernet
  encapsulation dot1q 33
  rewrite ingress tag pop 1 symmetric
  bridge-domain 77
 !
 service instance 17 ethernet
  encapsulation untagged
  bridge-domain 17
 !
end

Router# show platform ptp stats detailed
Statistics for PTP clock 0
###############################
Number of ports : 1
Pkts Sent       : 4793
Pkts Rcvd       : 26531
Pkts Discarded  : 0

LAST FLL STATE
###################
Normal loop : Number of Transitions = 0 and Last transition at : 00:00:00.000 UTC Mon Jan 1 1900 
Bridge state: Number of Transitions = 0 and Last transition at : 00:00:00.000 UTC Mon Jan 1 1900 
Holdover state : Number of Transitions = 1 and Last transition at : 12:08:38.774 UTC Thu Jun 19 2014

        Statistics for PTP clock port 1
        ##################################
        Pkts Sent        : 4793
        Pkts Rcvd        : 26531
        Pkts Discarded   : 0
        Signals Rejected : 0
        Statistics for L2 Multicast packets 
        ###################################
        Multicast address : 011b.1900.0000
        Announces Sent    : 0
        Syncs Sent        : 0
        Follow Ups Sent   : 0
        Delay Reqs Sent   : 4793
        Delay Resps Sent  : 0
        Signals Sent      : 0
        Packets Discarded : 0

                Statistics for peer 1
                ########################
                L2 address        : 4055.3989.728b
                Announces Sent    : 0
                Announces Rcvd    : 37
                Syncs Sent        : 0
                Syncs Rcvd        : 4752
                Follow Ups Sent   : 0
                Follow Ups Rcvd   : 4752
                Delay Reqs Sent   : 0
                Delay Reqs Rcvd   : 0
                Delay Resps Sent  : 0
                Delay Resps Rcvd  : 4753
                Mgmts Sent Rcvd   : 0
                Mgmts Rcvd        : 0
                Signals Sent      : 0
                Signals Rcvd      : 0
                Packets Discarded : 0

                Statistics for peer 2
                ########################
                L2 address        : 4055.3989.78a3
                Announces Sent    : 0
                Announces Rcvd    : 31
                Syncs Sent        : 0
                Syncs Rcvd        : 4069
                Follow Ups Sent   : 0
                Follow Ups Rcvd   : 4069
                Delay Reqs Sent   : 0
                Delay Reqs Rcvd   : 0
                Delay Resps Sent  : 0
                Delay Resps Rcvd  : 4068
                Mgmts Sent Rcvd   : 0
                Mgmts Rcvd        : 0
                Signals Sent      : 0
                Signals Rcvd      : 0
                Packets Discarded : 0

Verifying PTP Configuration on the 1588V2 Primary in Unicast Mode

A typical configuration on a 1588V2 primary is: 


ptp clock ordinary domain 0
tod 0/0 cisco
input 1pps 0/0
clock-port PRIMARY master
transport ipv4 unicast interface Lo20 negotiation

Use the show ptp clock running domain command to display the PTP clock configuration: 


Router# show ptp clock running domain 0
						PTP Ordinary Clock [Domain 0]
				State          Ports          Pkts sent      Pkts rcvd      
				FREQ_LOCKED				 1 				1757273			 599954
						PORT SUMMARY
Name 					Tx Mode      Role         Transport    State        Sessions
o 				 	unicast      master						 Lo20         Master							 5
						SESSION INFORMATION
o [Lo20] [Sessions 5]
Peer addr			 Pkts in			 Pkts out			 In Errs			 Out Errs
9.9.9.14			 120208			 344732			 0			 0
9.9.9.13			 120159			 344608			 0			 0
9.9.9.11			 120148			 343955			 0			 0
9.9.9.12			 119699			 342863			 0			 0
9.9.9.10			 119511			 342033			 0			 0

Use the show platform ptp stats command to display the PTP statistics: 


Statistics for PTP clock 0
###############################
Number of ports : 1
Pkts Sent : 1811997
Pkts Rcvd : 619038
Pkts Discarded : 0
Statistics for PTP clock port 1
##################################
Pkts Sent : 1811997
Pkts Rcvd : 619038
Pkts Discarded : 0
Signals Rejected : 0
Statistics for peer 1
########################
IP addr : 9.9.9.14
Pkts Sent : 355660
Pkts Rcvd : 124008
Statistics for peer 2
########################
IP addr : 9.9.9.13
Pkts Sent : 355550
Pkts Rcvd : 123973
Statistics for peer 3
########################
IP addr : 9.9.9.11
Pkts Sent : 354904
Pkts Rcvd : 123972
Statistics for peer 4
########################
IP addr : 9.9.9.12
Pkts Sent : 353815
Pkts Rcvd : 123525
Statistics for peer 5
########################
IP addr : 9.9.9.10
Pkts Sent : 352973
Pkts Rcvd : 123326

Verifying PTP Configuration on the 1588V2 Primary in Multicast Mode

A typical configuration on a 1588V2 primary is: 


ptp clock boundary domain 0 
 clock-port SUBORDINATE slave
  transport ipv4 unicast interface Lo45 negotiation
  clock source 40.40.40.1
clock-port PRIMARY master
    transport ethernet multicast bridge-domain 1

Use the show ptp clock running domain command to display the PTP clock configuration: 


Router# show ptp clock running domain 0

                      PTP Boundary Clock [Domain 0] 

         State          Ports          Pkts sent      Pkts rcvd      Redundancy Mode

         PHASE_ALIGNED  2              242559956      189887918      Track all

                               PORT SUMMARY
                                                                        PTP Master
Name   Tx Mode      Role         Transport    State        Sessions     Port Addr

SUBORDINATE  unicast      slave        Lo45         Slave        1            40.40.40.1
PRIMARY mcast        master       Ethernet     Master       1            -


                             SESSION INFORMATION

SUBORDINATE [Lo45] [Sessions 1]

Peer addr          Pkts in    Pkts out   In Errs    Out Errs  

40.40.40.1         132729502  44138439   0          0         

PRIMARY [Ethernet] [Sessions 1]

Peer addr                          Pkts in    Pkts out   In Errs    Out Errs  

4c00.8287.1d33     [BD 1         ] 960676     960676     0          0

Use the show platform ptp state command to display the PTP servo state: 


         FLL State                     : 3 (Normal Loop)
         FLL Status Duration           : 687618 (sec)

         Forward Flow Weight           : 47.0
         Forward Flow Transient-Free   : 900 (900 sec Window)
         Forward Flow Transient-Free   : 3600 (3600 sec Window)
         Forward Flow Transactions Used: 200.0 (%)
         Forward Flow Oper. Min TDEV   : 5.0 (nsec)
         Forward Mafie                 : 0.0
         Forward Flow Min Cluster Width: 15000.0 (nsec)
         Forward Flow Mode Width       : 100.0 (nsec)

         Reverse Flow Weight           : 52.0
         Reverse Flow Transient-Free   : 900 (900 sec Window)
         Reverse Flow Transient-Free   : 3600 (3600 sec Window)
         Reverse Flow Transactions Used: 200.0 (%)
         Reverse Flow Oper. Min TDEV   : 6.0 (nsec)
         Reverse Mafie                 : 0.0
         Reverse Flow Min Cluster Width: 7500.0 (nsec)
         Reverse Flow Mode Width       : 100.0 (nsec)

         Frequency Correction          : 54.836 (ppb)
         Phase Correction              : 0.0 (ppb)

         Output TDEV Estimate          : 6.0 (nsec)
         Output MDEV Estimate          : 0.0 (ppb)

         Residual Phase Error          : 3.206 (nsec)
         Min. Roundtrip Delay          : 14.0 (nsec)

         Sync Packet Rate*             : 64 (pkts/sec)
         Delay Packet Rate*            : 64 (pkts/sec)

         Forward IPDV % Below Threshold: 0.0
         Forward Maximum IPDV          : 0.0 (usec)
         Forward Interpacket Jitter    : 0.0 (usec)

         Reverse IPDV % Below Threshold: 0.0
         Reverse Maximum IPDV          : 0.0 (usec)
         Reverse Interpacket Jitter    : 0.0 (usec)
         Note: The maximum rates for Sync and Delay packets will be approximately 64 pps.

Use the show platform ptp stats detailed command to display the PTP statistics: 

Router#sh platform ptp stats detailed 
Statistics for PTP clock 0
###############################
Number of ports : 2
Pkts Sent       : 242525543
Pkts Rcvd       : 189865083
Pkts Discarded  : 0

LAST FLL STATE 
###################
Normal loop : Number of Transitions = 1 and Last transition at : 15:51:16.155 UTC Mon Apr 21 2014
Bridge state: Number of Transitions = 0 and Last transition at : 00:00:00.000 UTC Mon Jan 1 1900
Holdover state : Number of Transitions = 0 and Last transition at : 00:00:00.000 UTC Mon Jan 1 1900

        Statistics for PTP clock port 1
        ##################################
        Pkts Sent        : 44132739
        Pkts Rcvd        : 132712363
        Pkts Discarded   : 0
        Signals Rejected : 0
                Statistics for peer 1
                ########################
                IP address        : 40.40.40.1
                Announces Sent    : 0
                Announces Rcvd    : 344686
                Syncs Sent        : 0
                Syncs Rcvd        : 44119383
                Follow Ups Sent   : 0
                Follow Ups Rcvd   : 44119383
                Delay Reqs Sent   : 44119179
                Delay Reqs Rcvd   : 0
                Delay Resps Sent  : 0
                Delay Resps Rcvd  : 44115351
                Mgmts Sent Rcvd   : 0
                Mgmts Rcvd        : 0
                Signals Sent      : 13560
                Signals Rcvd      : 13560
                Packets Discarded : 0

        Statistics for PTP clock port 2
        ##################################
        Pkts Sent        : 198392804
        Pkts Rcvd        : 57152720
        Pkts Discarded   : 0
        Signals Rejected : 0
        Statistics for L2 Multicast packets 
        ###################################
        Multicast address : 011b.1900.0000
        Announces Sent    : 343722
        Syncs Sent        : 83733919
        Follow Ups Sent   : 83733919
        Delay Reqs Sent   : 0
        Delay Resps Sent  : 0
        Signals Sent      : 0
        Packets Discarded : 0

                Statistics for peer 2
                ########################
                L2 address        : 4c00.8287.1d33
                Announces Sent    : 0
                Announces Rcvd    : 0
                Syncs Sent        : 0
                Syncs Rcvd        : 0
                Follow Ups Sent   : 0
                Follow Ups Rcvd   : 0
                Delay Reqs Sent   : 0
                Delay Reqs Rcvd   : 954979
                Delay Resps Sent  : 954979
                Delay Resps Rcvd  : 0
                Mgmts Sent Rcvd   : 0
                Mgmts Rcvd        : 0
                Signals Sent      : 0
                Signals Rcvd      : 0
                Packets Discarded : 0

Note

In primary node, the Delay Resps packet sent to a specific peer is a response to the Delay Reqs packet. Hence, the sh platform ptp stats detailed command displays the details of both the sent and received packets.

PTP Hybrid Clock

To improve the clock quality, you can either improve the oscillator class or reduce the number of hops between the primary and the subordinate. In PTP hybrid mode, the oscillator class is improved by using a physical layer clock (sourced from a stratum-1 clock) instead of the available internal oscillator. The PTP hybrid mode is supported for ordinary clock (in subordinate mode only) and boundary clock.

Configuring a Hybrid Ordinary Clock

Complete the following steps to configure a hybrid clocking in ordinary subordinate clock mode:

Before you begin

When configuring a hybrid clock, ensure that the frequency and phase sources are traceable to the same primary clock.


Note
  • Hybrid mode is not supported when PTP ordinary clock is in the primary mode.
  • Hybrid clock is not supported with ToP as network-clock. It needs a valid physical clock source, for example, Sync-E/BITS/10M/TDM.
Procedure
  Command or Action Purpose
Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

ptp clock ordinary domain domain hybrid

Example:

Router(config)# ptp clock ordinary domain 0

Configures the PTP clock as an ordinary clock and enters clock configuration mode.

  • domain —The PTP clocking domain number. Valid values are from 0 to 127.
  • hybrid —(Optional) Enables the PTP boundary clock to work in hybrid mode. Enables the hybrid clock such that the output of the clock is transmitted to the remote slaves.
Step 4

clock-port port-name slave

Example:

Router(config-ptp-clk)# clock-port subordinate slave

Sets the clock port to PTP subordinate mode and enters clock port configuration mode. In subordinate mode, the port exchanges timing packets with a PTP primary clock.

Step 5

Do one of the following:

  • transport ipv4 unicast interface interface-type interface-number
  • transport ethernet multicast bridge-domain bridge-id
Example:
Router(config-ptp-port)# transport ipv4 
unicast interface loopback 0

Specifies the transport mechanism for clocking traffic; you can use IPv4 or Ethernet transport.

  • interface-type —The type of the interface.
  • interface-number —The number of the interface.

Configures a bridge domain.

  • bridge-id —Identifier for the bridge domain instance. The range is from 1 to 4094.
Note 

Effective with Cisco IOS Release 15.5(2)S onwards, VLAN interface (with DHCP assigned IP or static IP) is supported.

Step 6

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 5.5.5.5

Specifies the address of a PTP primary clock. You can specify a priority value as follows:

  • No priority value—Assigns a priority value of 0, the highest priority.
  • 1—Assigns a priority value of 1.
  • 2—Assigns a priority value of 2.
  • 3—Assigns a priority value of 3.

Repeat this step for each additional primary clock. You can configure up to four primary clocks.

Note 

Priority is used as an index for the configured clock sources and is not a criteria for the BMCA.

Step 7

clock source source-address

Example:

Router(config-ptp-port)# clock source 8.8.8.1

Specifies the address of a PTP primary clock.

Step 8

announce timeout value

Example:

Router(config-ptp-port)# announce timeout 8

(Optional) Specifies the number of PTP announcement intervals before the session times out.

  • value —The range is from 1 to 10. The default is 3.
Step 9

delay-req interval interval

Example:

Router(config-ptp-port)# delay-req interval 1

(Optional) Configures the minimum interval allowed between PTP delay request messages.

The intervals are set using log base 2 values, as follows:

  • 5—1 packet every 32 seconds
  • 4—1 packet every 16 seconds
  • 3—1 packet every 8 seconds
  • 2—1 packet every 4 seconds
  • 1—1 packet every 2 seconds
  • 0—1 packet every second
  • -1—1 packet every 1/2 second, or 2 packets per second
  • -2—1 packet every 1/4 second, or 4 packets per second
  • -3—1 packet every 1/8 second, or 8 packets per second
  • -4—1 packet every 1/16 seconds, or 16 packets per second.
  • -5—1 packet every 1/32 seconds, or 32 packets per second.
  • -6—1 packet every 1/64 seconds, or 64 packets per second.
  • -7—1 packet every 1/128 seconds, or 128 packets per second.

The default is -6.

Step 10

sync interval interval

Example:

Router(config-ptp-port)# sync interval -5

(Optional) Specifies the interval used to send PTP synchronization messages. The intervals are set using log base 2 values. The Cisco ASR 901 router supports the following values:

  • -5—1 packet every 1/32 seconds, or 32 packets per second.
  • -6—1 packet every 1/64 seconds, or 64 packets per second.

The default is -6.

Step 11

end

Example:

Router(config-ptp-port)# end

Exits clock port configuration mode and enters privileged EXEC mode.

Configuring a Hybrid Boundary Clock

Complete the following steps to configure a hybrid clocking in PTP boundary clock mode.

Before you begin

When configuring a hybrid clock, ensure that the frequency and phase sources are traceable to the same primary clock.


Note

Hybrid clock is not supported with ToP as network-clock. It needs a valid physical clock source, for example, Sync-E/BITS/10M/TDM.

Procedure
  Command or Action Purpose
Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

ptp clock boundary domain domain hybrid

Example:

Router(config)# ptp clock boundary domain 0 hybrid

Configures the PTP boundary clock and enters clock configuration mode.

  • domain —The PTP clocking domain number. Valid values are from 0 to 127.
  • hybrid —(Optional) Enables the PTP boundary clock to work in hybrid mode. Enables the hybrid clock such that the output of the clock is transmitted to the remote slaves.
Step 4

clock-port port-name slave

Example:

Router(config-ptp-clk)# clock-port subordinate slave

Sets the clock port to PTP subordinate mode and enters the clock port configuration mode. In subordinate mode, the port exchanges timing packets with a PTP primary clock.

Step 5

Do one of the following:

  • transport ipv4 unicast interface interface-type interface-number [negotiation]
  • transport ethernet multicast bridge-domain bridge-id
Example:
Router(config-ptp-port)# transport ipv4 unicast 
interface loopback 0 negotiation

Specifies the transport mechanism for clocking traffic; you can use IPv4 or Ethernet transport.

  • interface-type —The type of the interface.
  • interface-number —The number of the interface.
  • negotiation —(Optional) Enables dynamic discovery of subordinate devices and their preferred format for sync interval and announce interval messages.

Configures a bridge domain.

  • bridge-id —Identifier for the bridge domain instance. The range is from 1 to 4094.
Note 

Effective with Cisco IOS Release 15.5(2)S onwards, VLAN interface (with DHCP assigned IP or static IP) is supported.

Step 6

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 5.5.5.5

Specifies the address of a PTP primary clock. You can specify a priority value as follows:

  • No priority value—Assigns a priority value of 0, the highest priority.
  • 1—Assigns a priority value of 1.
  • 2—Assigns a priority value of 2.
  • 3—Assigns a priority value of 3.

Repeat this step for each additional primary clock. You can configure up to four primary clocks.

Note 

Priority is used as an index for the configured clock sources and is not a criteria for the BMCA.

Step 7

clock source source-address

Example:

Router(config-ptp-port)# clock source 133.133.133.133

Specifies the address of a PTP primary clock.

Step 8

clock-port port-name primary

Example:

Router(config-ptp-port)# clock-port primary master

Sets the clock port to PTP primary mode. In primary mode, the port exchanges timing packets with PTP subordinate devices.

Note 
The primary clock-port does not establish a clocking session until the subordinate clock-port is phase aligned.
Step 9

transport ipv4 unicast interface interface-type interface-number [negotiation]

Example:

Router(config-ptp-port)# transport ipv4 unicast 
interface Loopback 1 negotiation

Sets port transport parameters.

  • interface-type —The type of the interface.
  • interface-number —The number of the interface.
  • negotiation —(Optional) Enables dynamic discovery of subordinate devices and their preferred format for sync interval and announce interval messages.
Note 

Effective with Cisco IOS Release 15.5(2)S onwards, VLAN interface (with DHCP assigned IP or static IP) is supported. The option of using dynamic IP for PTP over VLAN is generally meant for a subordinate interface. Though the implementation supports dynamic IP assignment on the PTP primary, you must configure the dynamically assigned IP in “clock source ” command on the PTP subordinate.

Step 10

exit

Example:

Router(config-ptp-port)# exit

Exits clock port configuration mode.

Note 
The hybrid clocking in PTP boundary clock mode will work as a PTP ordinary clock when frequency source is not selected.
Note 
The hybrid clock (HC) relies on an external clock source for frequency recovery while phase is recovered through PTP. Once the HC reaches the normal or phase aligned state, and if the external frequency channel is active and traceable to PRC, then the HC moves into the phase aligned state even when the PTP link is down.

Verifying Hybrid modes

Use the show running-config | section ptp command to display the sample output. 


Router# show running-config | section ptp
ptp clock ordinary domain 20 hybrid
 time-properties gps timeScaleTRUE currentUtcOffsetValidTRUE leap59FALSE leap61FALSE 35
 clock-port subordinate slave
  transport ipv4 unicast interface Lo17
  clock source 17.17.1.1

Use the show ptp clock running domain command to display the sample output. 


Router# show ptp clock running domain
                      PTP Ordinary Clock [Domain 20] [Hybrid]
         State          Ports          Pkts sent      Pkts rcvd      Redundancy Mode
         PHASE_ALIGNED  1              27132197       81606642       Track all
                               PORT SUMMARY
                                                                       PTP Master
Name  Tx Mode      Role         Transport    State        Sessions     Port Addr
Subordinate unicast      slave        Lo17         Slave        1            17.17.1.1

Use the show platform ptp channel_status command to display the sample output after PTP is in normal state. 


Router#show platform ptp channel_status
Configured channels : 2
channel[0]: type=0, source=0, frequency=0, tod_index=0, freq_prio=5
            time_enabled=y, freq_enabled=y, time_prio=1 freq_assumed_QL=0
            time_assumed_ql=0, assumed_ql_enabled=n
channel[1]: type=6, source=17, frequency=0, tod_index=0, freq_prio=2
            time_enabled=n, freq_enabled=y, time_prio=0 freq_assumed_QL=0
            time_assumed_ql=0, assumed_ql_enabled=n
  Channel 0:    Frequency       Time
---------------------------------------
       Status  OK           OK
       Weight     0               100
       QL         9               9
---------------------------------------
   QL is not read externally.   Fault status: 00000000
  Channel 1:    Frequency       Time
---------------------------------------
       Status  OK           Disabled
       Weight     100             0
       QL         9               9
---------------------------------------
   QL is not read externally.   Fault status: 00000000

Configuration Examples for BMCA

This section provides the following configuration examples:

Example: Configuring a Subordinate Ordinary Clock in BMCA

The following is a sample configuration of a subordinate ordinary clock in BMCA: 

!
  ptp clock ordinary domain 0 
  clock-port subordinate slave
  transport ipv4 unicast interface Lo30 negotiation
  clock source 22.22.22.1
  clock source 66.66.66.1 1
  clock source 33.33.33.1 2
  clock source 44.44.44.1 3
!

Example: Configuring a Boundary Clock in BMCA

The following is a sample configuration of a boundary clock in BMCA: 

!
  ptp clock boundary domain 0
  clock-port SLAVE slave
  transport ipv4 unicast interface Lo30 negotiation
  clock source 22.22.22.1
  clock source 66.66.66.1 1
  clock source 33.33.33.1 2
  clock source 44.44.44.1 3
  clock-port MASTER master
  transport ipv4 unicast interface Lo50 negotiation
!

Note

The ordinary clock and boundary clock configurations remain the same for both hybrid clock and hybrid boundary clock. Change the PTP domain configuration to ptp clock ordinary domain 0 hybrid for a hybrid clock and ptp clock boundary domain 0 hybrid for a hybrid boundary clock. An appropriate frequency source (SyncE) will be enabled for the hybrid mode.

SSM and PTP Interaction

PTP carries clock quality in its datasets in the structure defined by the IEEE 1588 specification. The Ordinary Clock (OC) master carries the Grand Master (GM) clock quality in its default dataset which is sent to the downstream OC slaves and Boundary Clocks (BC). The OC slaves and BCs keep the GM clock quality in their parent datasets.

If the T0 clock in Cisco ASR 901 is driven by the clock recovered from the OC Slave (if ToP0/12 is selected as clock-source), then the clock quality in the PTP parent dataset represents the quality of the ToP0/12 input clock. This should be informed to the netsync process for proper clock selection. This is done by translating clockClass data field in clock quality to QL-values expected by netsync.

On the other hand, if Cisco ASR 901 serves as the OC Master, then the GM clock is the clock providing T0 clock to Cisco ASR 901 router. Hence, the T0 clock quality should be used by OC master to fill up clockClass in the clock quality field, in its default dataset. For this, the T0 output QL-value should be mapped to the clockClass value according to ITU-T Telecom Profile, and set in the default dataset of the OC Master. This QL-value is then transmitted to the PTP slaves and BC downstream.

ClockClass Mapping

The Cisco ASR 901 router supports two methods of mapping PTP ClockClass to SSM/QL-value:

  • Telecom Profile based on ITU-T G.8265.1/Y.1365.1 PTP (Telecom) Profile for Frequency Synchronization [2]
  • Default method of calculating clockClass based on IEEE 1588v2 PTP specification.

Telecom Profiles

The Telecom Profile specifies an alternative algorithm for selecting between different master clocks, based on the quality level (QL) of master clocks and on a local priority given to each master clock. Release 3.11 introduces support for telecom profiles using a new configuration method, which allow you to configure a clock to use the G.8265.1 recommendations for establishing PTP sessions, determining the best master clock, handling SSM, and mapping PTP classes.

PTP Redundancy

PTP redundancy is an implementation on different clock nodes by which the PTP slave clock node achieves the following:

  • Interact with multiple master ports such as grand master, boundary clock nodes, and so on.
  • Open PTP sessions.
  • Select the best master from the existing list of masters (referred to as the primary PTP master port or primary clock source).
  • Switch to the next best master available in case the primary master fails, or the connectivity to the primary master fails.

Note
The Cisco ASR 901 Series Router supports unicast-based timing as specified in the 1588-2008 standard. Hybrid mode is not supported with PTP 1588 redundancy.

Configuring Telecom Profile in Slave Ordinary Clock

Complete the following steps to configure the telecom profile in slave ordinary clock.

Before you begin
  • When configuring the Telecom profile, ensure that the master and slave nodes have the same network option configured.
  • Negotiation should be enabled for master and slave modes.
  • Cisco ASR 901 router must be enabled using the network-clock synchronization mode QL-enabled command for both master and slave modes.

Note
  • Telecom profile is not applicable for boundary clocks. It is only applicable for ordinary clocks.
  • Hybrid mode with OC-MASTER is not supported.
Procedure
  Command or Action Purpose
Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

ptp clock ordinary domain domain-name

Example:

Router(config)# ptp clock ordinary domain 4

Configures the PTP ordinary clock and enters clock configuration mode.

  • domain —The PTP clocking domain number. Valid values are from 4 to 23.
Step 4

clock-port port-name {master | slave} profile g8265.1

Example:

Router(config-ptp-clk)# clock-port Slave slave

Sets the clock port to PTP slave mode and enters clock port configuration mode. In slave mode, the port exchanges timing packets with a PTP master clock.

The profile keyword configures the clock to use the G.8265.1 recommendations for establishing PTP sessions, determining the best master clock, handling SSM, and mapping PTP classes.

Note 
Using a telecom profile requires that the clock have a domain number of 4–23.
Step 5

transport ipv4 unicast interface interface-type interface-number

Example:

Router(config-ptp-port)# transport ipv4 
unicast interface loopback 0

Sets port transport parameters.

  • interface-type —The type of the interface.
  • interface-number —The number of the interface.
Note 

Effective with Cisco IOS Release 15.5(2)S onwards, VLAN interface (with DHCP assigned IP or static IP) is supported.

Step 6

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 8.8.8.1

Specifies the address of a PTP master clock. You can specify a priority value as follows:

  • No priority value—Assigns a priority value of 0, the highest priority.
  • 1—Assigns a priority value of 1.
  • 2—Assigns a priority value of 2.
Step 7

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 8.8.8.2 1

Specifies the address of an additional PTP master clock; repeat this step for each additional master clock. You can configure up to four master clocks.

Step 8

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 8.8.8.3 2

Specifies the address of an additional PTP master clock; repeat this step for each additional master clock. You can configure up to four master clocks.

Step 9

clock source source-address priority

Example:

Router(config-ptp-port)# clock source 8.8.8.4 3

Specifies the address of an additional PTP master clock; repeat this step for each additional master clock. You can configure up to four master clocks.

Step 10

end

Example:

Router(config-ptp-port)# end

Exits clock port configuration mode and enters privileged EXEC mode.

Configuring Telecom Profile in Master Ordinary Clock

Complete the following steps to configure the telecom profile in the master ordinary clock.

Before you begin
  • When configuring the telecom profile, ensure that the master and slave nodes have the same network option configured.
  • Negotiation should be enabled for master and slave modes.
  • Cisco ASR 901 router must be enabled using the network-clock synchronization mode QL-enabled command for both master and slave modes.

Note
  • Telecom profile is not applicable for boundary clocks. It is only applicable for ordinary clocks.
  • Hybrid mode with OC-MASTER is not supported.
Procedure
  Command or Action Purpose
Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

ptp clock ordinary domain domain-name

Example:

Router(config)# ptp clock ordinary domain 4

Configures the PTP ordinary clock and enters clock configuration mode.

  • domain —The PTP clocking domain number. Valid values are from 4 to 23.
Step 4

clock-port port-name {master | slave} profile g8265.1

Example:

Router(config-ptp-clk)# clock-port 
Master master profile g8265.1

Sets the clock port to PTP master and enters clock port configuration mode. In master mode, the port exchanges timing packets with a PTP slave devices.

The profile keyword configures the clock to use the G.8265.1 recommendations for establishing PTP sessions, determining the best master clock, handling SSM, and mapping PTP classes.

Note 
Using a telecom profile requires that the clock have a domain number of 4–23.
Step 5

transport ipv4 unicast interface interface-type interface-number

Example:

Router(config-ptp-port)# transport ipv4 
unicast interface loopback 0

Sets port transport parameters.

  • interface-type —The type of the interface.
  • interface-number —The number of the interface.
Note 

Effective with Cisco IOS Release 15.5(2)S onwards, VLAN interface (with DHCP assigned IP or static IP) is supported. The option of using dynamic IP for PTP over VLAN is generally meant for a Slave interface. Though the implementation supports dynamic IP assignment on the PTP master, you must configure the dynamically assigned IP in “clock source ” command on the PTP Slave.

Step 6

end

Example:

Router(config-ptp-port)# end

Exits clock port configuration mode and enters privileged EXEC mode.

Verifying Telecom profile

Use the show ptp port running detail command to display the details of PTP masters configured for a Telecom profile slave. The PTSF and Alarm fields indicate the alarm experienced by the SLAVE clock for the MASTER clock. 


Router#show ptp port running detail
PORT [slave] CURRENT PTP MASTER PORT
  Protocol Address: 208.1.1.3
  Clock Identity: 0xE4:D3:F1:FF:FE:FF:BC:E4
PORT [slave] PREVIOUS PTP MASTER PORT
  Protocol Address: 208.1.1.1
  Clock Identity: 0xE4:D3:F1:FF:FE:22:F2:C8
  Reason: 
PORT [slave] LIST OF PTP MASTER PORTS
LOCAL PRIORITY 0
  Protocol Address: 208.1.1.1
Clock Identity: 0xE4:D3:F1:FF:FE:22:F2:C8
  PTSF Status: 
  Alarm In Stream: 
  Clock Stream Id: 0
  Priority1: 128
  Priority2: 128
  Class: 102
  Accuracy: Unknown
  Offset (log variance): 0
  Steps Removed: 0
LOCAL PRIORITY 1
  Protocol Address: 208.1.1.3
  Clock Identity:  0xE4:D3:F1:FF:FE:FF:BC:E4
  PTSF Status: 
  Alarm In Stream: 
  Clock Stream Id: 0
  Priority1: 128
  Priority2: 128
  Class: 100
  Accuracy: Unknown
  Offset (log variance): 0
  Steps Removed: 0
LOCAL PRIORITY 2
  Protocol Address: 208.1.1.4
  Clock Identity:  0x40:55:39:FF:FE:89:44:48
  PTSF Status: 
  Alarm In Stream: 
  Clock Stream Id: 0
  Priority1: 128
  Priority2: 128
  Class: 102
  Accuracy: Unknown
  Offset (log variance): 0
  Steps Removed: 0

Use the show ptp clock running domain command to display the sample output. 


Router#show ptp clock running domain 10
                      PTP Ordinary Clock [Domain 10]
         State          Ports          Pkts sent      Pkts rcvd      Redundancy Mode
         PHASE_ALIGNED  1              22459694       67364835       Track all
                               PORT SUMMARY
                                                                       PTP Master
Name  Tx Mode      Role         Transport    State        Sessions     Port Addr
SLAVE unicast      slave        Lo40         Slave        1            4.4.4.3
                             SESSION INFORMATION
SLAVE [Lo40] [Sessions 1]
Peer addr          Pkts in    Pkts out   In Errs    Out Errs
4.4.4.3            60023902   20011138   0          0

Setting the TimeProperties

The timeProperties dataset members (except timeTraceable and frequencyTraceable) can be individually set by using the time-properties command.


Caution

The time-properties command does not perform any input validation; use this command with caution.

The following is an example of the time-properties command: 


Router(config-ptp-clk)# time-properties atomic-clock timeScaleTRUE currentUtcOffsetValidTRUE leap59TRUE leap61FALSE 34
slave#show ptp clock dataset time-properties
CLOCK [Ordinary Clock, domain 0]
	Current UTC Offset Valid: TRUE
	Current UTC Offset: 34
	Leap 59: TRUE
	Leap 61: FALSE
	Time Traceable: TRUE
	Frequency Traceable: TRUE
	PTP Timescale: TRUE
	Time Source: Atomic

The values of Time Traceable and Frequency Traceable are determined dynamically.

ASR 901 Negotiation Mechanism

The Cisco ASR 901 router supports a maximum of 36 slaves, when configured as a negotiated 1588V2 master. For a slave to successfully negotiate with the Cisco ASR 901 master, it should request sync and announce packet rates that are not greater than the sync and announce rate that are currently set in the master.

For example, if the sync interval on the master is -5 (32 packets/second), and if the slave tries to negotiate a value of sync interval value of -6 (64 packets/second), the negotiation fails.

Static Unicast Mode

A clock destination can be added when the master is configured in the static unicast mode (by configuring the transport without the negotiation flag). The master does not communicate with any other slave, in this configuration. 


Router(config-ptp-port)#clock destination
 9.9.9.10

VRF-Aware Precision Time Protocol

Effective from Cisco IOS Release 15.4(3)S, the Cisco ASR 901 Router supports VRF-aware PTP. PTP support over virtual routing and forwarding (VRF) instance-enabled interfaces allows the PTP loopback interface to be part of VRF rather than maintaining the loopback addresses in the global routing table. This enables the service providers to reuse the same IP address for multiple loopback interfaces by configuring PTP loopback under VRF. This enables you to use PTP over VRF lite and PTP over VRF with MPLS network. You can configure a loopback interface as part of a VRF instance or a global routing table depending on the requirement.

Configuring VRF-Aware Precision Time Protocol

To configure VRF-aware PTP, perform the following tasks:

Restrictions

  • Bridge domains used internally by PTP are not available to user. To view the list of such internally used bridge domains, use the show vlan internal usage command.

  • VRF-aware PTP feature is supported only on loopback interfaces with or without VRFs.

  • The PTP with route leaks is not supported when the master is in global routing table and the slave is in vrf table.

Procedure
  Command or Action Purpose
Step 1

enable

Example:
Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2

configure terminal

Example:
Router# configure terminal

Enters global configuration mode.

Step 3

ip vrf vrf-name

Example:
Router(config)# ip vrf green

Creates a VPN routing and forwarding (VRF) instance.

  • vrf-name—Name assigned to the VRF.
Step 4

rd route-distinguisher

Example:
Router(config-vrf)# rd 100:1

Specifies a route distinguisher (RD) for a VRF instance.

  • route-distinguisher —An autonomous system number (ASN) and an arbitrary number (for example, 101:1), or an IP address and an arbitrary number (for example, 192.168.122.15:1).
Step 5

route-target export route-target-ext-community

Example:
Router(config-vrf)# route-target export 100:1

Creates lists of export route-target extended communities for the specified VRF.

  • route-target-ext-community —An autonomous system number (ASN) and an arbitrary number (for example, 100:1) or an IP address and an arbitrary number (for example, 192.168.122.15:1). Enter the route-distinguisher value specified in 4.
Step 6

route-target import route-target-ext-community

Example:
Router(config-vrf)# route-target import 100:1

Creates lists of import route-target-extended communities for the specified VRF.

  • route-target-ext-community —An autonomous system number (ASN) and an arbitrary number (for example, 100:1), or an IP address and an arbitrary number (for example, 192.168.122.15:1). Enter the route-distinguisher value specified in 4.
Step 7

exit

Example:
Router(config-vrf)# exit

Exits VRF configuration mode.

Step 8

interface vlanvlan-id

Example:
Router(config)# interface vlan 4

Configures a VLAN interface and enters interface configuration mode.

  • vlan-id —VLAN identifier. VLAN range is from 1 to 4093.
Step 9

ip vrf forwarding vrf-name

Example:
Router(config-if)# ip vrf forwarding green

Associates a VRF with an interface or subinterface.

  • vrf-name —Name assigned to the VRF. Enter the value specified in Step 3.
Step 10

ip address address mask

Example:
Router(config-if)# ip address 4.4.4.2 255.255.255.0

Sets a primary or secondary IP address for the interface. By default, sets the primary IP address.

  • address —IP address
  • mask —Subnet mask
Step 11

exit

Example:
Router(config-if)# exit

Exits interface configuration mode.

Step 12

router ospf process-id [vrf vrf-name ]

Example:
Router(config)# router ospf 2 vrf green

Configures an OSPF routing process and enters router configuration mode.

  • process-id —Internally-used identification parameter for an OSPF routing process. It is locally assigned and can be any positive integer. A unique value is assigned for each OSPF routing process.
  • vrf-name —Name assigned to the VRF. Enter the value specified in 3.
Step 13

network ip-address wildcard-mask area area-id

Example:
Router(config-router)# router ospf 2 vrf green

Configures the interfaces on which OSPF runs and defines the area ID for those interfaces.

  • ip-address —IP address
  • wildcard-mask—IP-address-type mask that includes optional bits.
  • area-id—Area that is to be associated with the OSPF address range. It can be specified as either a decimal value or as an IP address. If you intend to associate areas with IP subnets, you can specify a subnet address as the value of the area-id argument.
    Note 
    Repeat this step to configure different interfaces on which OSPF runs, and to define the area ID for those interfaces.
Step 14

exit

Example:
Router(config-router)# exit

Exits router configuration mode.

Examples

The following is a sample configuration of VRF-aware PTP: 


!
ip vrf green
rd 100:1
route-target export 100:1
route-target import 100:1
!
!
interface Vlan4
ip vrf forwarding green
ip address 4.4.4.2 255.255.255.0
mpls ip
!
interface Loopback4
ip vrf forwarding green
ip address 50.50.50.50 255.255.255.255
!
router ospf 2 vrf green
network 4.4.4.0 0.0.0.255 area 2
network 50.50.50.50 0.0.0.0 area 2
!
!
end

 ptp clock ordinary domain 0
	Clock-port slave slave
	Transport ipv4 unicast interface loopback 4 negotiation
	Clock source 5.5.5.5
!

Configuring ToD on 1588V2 Slave

Use the following commands configure ToD on the 1588V2 slave:

Command

Purpose

tod {slot|subslot} {cisco/ntp|ubx|nmea}

Configures ToD on 1588V2.

1pps-out 1 PPS offset in ns pulse width pulse width unit

Configures 1 PPS output parameters.

This example shows the ToD configuration on the 1588V2 slave: 


Router# config terminal 
Router(config)# ptp clock ordinary domain 0
Router(config-ptp-clk)# tod 0/0 cisco
Router(config-ptp-clk)# 1pps-out 0 2250 ns
Router(config-ptp-clk)# clock-port SLAVE slave
Router(config-ptp-port)# transport ipv4 unicast interface Lo10 negotiation
Router(config-ptp-port)# clock source 1.1.1.1
Router(config-ptp-port)# end

1588v2 Phase Asymmetry Correction

In Optical Transport Network (OTN ) network based deployments, though the PDV produced by the network is within the G.8261 limits and asymmetry created by traffic is also less, the OTN elements may add a fixed asymmetry (about 4-5usec) when the OTN element is reboots or optical link related event occurs. The asymmetry detection is tied to the BMCA clock switchover and correction is supported from Cisco IOS Release 15.5(1)S on the Cisco ASR 901 Series Routers. This mechanism is enabled on both ordinary clock (OC) slave and boundary clock (BC) slave.

The following diagram indicates the design statement of asymmetry correction at a high level.

Figure 5. 1588v2 Phase Asymmetry Correction

When the BMCA algorithm selects a new master, the previous recovered servo-reported phase offset is saved as fixed-phase-offset and a flag is set to indicate to use this value instead of the servo-reported phase offset. This results in phase holdover from the previous master until the path to new master is available. The BMCA master and the servo events portray a path to the new master by comparing the fixed-phase-offset value to the servo-reported phase offset from the new master. The delta phase is computed and applied to servo, which enables the servo to come out of phase holdover.

For certain failures over one path, the delay asymmetry could differ by up to 4 usec after restoration, which would shift the phase or time by up to 2 usec. The valid path continues to provide an accurate phase or time. The root cause for this behavior is the underlying optical network that causes the asymmetry variation and forces the system to do an internal allocation during a disruption. When a link goes down, the underlying optical network fails to allow the same buffer, causing the variation.

In the following scenarios, the asymmetry is corrected after an optical link disruption, based on the persistent PTP link:

Initially, the symmetry is corrected based on measurements and manual adjustment on the router. For that:

  • Time Link 1 is marked as ACTIVE.

  • Time Link 2 is marked as STANDBY.


Note

The initial path asymmetry is compensated by using an external measurement device and compensates the 1pps offset.

In Scenario 1, the optical link 1 goes down and comes back after a while. Here:

  • Time is persistent on Link 2 and is used as ACTIVE.

  • When Link 1 comes back; time from this link is marked as suspicious.

  • Asymmetry is adjusted based on Link 2, enabling it to be in sync with Link 1.

  • Link 1 is marked as ACTIVE.

  • Link 2 is marked as STANDBY.

In Scenario 2, the optical link 2 goes down and comes back after a while. Here:

  • Time is persistent on Link 2 and is used as ACTIVE.

  • When Link 2 comes back; time from this link is marked as suspicious.

  • Asymmetry is adjusted based on Link 1, enabling it to be in sync with Link 2.

  • Link 2 is marked as ACTIVE.

  • Link 1 is marked as STANDBY.


Note

Both the above scenarios requires use of phase holdover mode, which becomes active when there is a Master switch. After the old link is restored, the SERVO learns the new path and applies the correction.

  • The PTP phase symmetry correction feature is supported only on IEEE1588v2 BMCA.

  • Delay asymmetry value should be enabled on the available master clock source if reference master is removed.

  • The delay asymmetry in the network should be measured exactly before its applied on the clock source.

  • The Hybrid Slave clock always remains in Normal_loop during a PTP master switch and hence, the newly calculated asymmetry is compensated after 10 minutes of the master switch.

  • If the selected PTP master before-reload is not the same after-reload, then the asymmetry table in flash is cleared to avoid using stale values for the new master.

  • Phase asymmetry is not supported in Telecom profile and PTP over Ethernet.

  • Phase asymmetry (phase correction and path asymmetry) is supported only in Ordinary Slave clock, Boundary Clock slave, Hybrid Slave clock, and Hybrid Boundary Slave clock.

  • Exact delay asymmetry value should be measured from the network path to the master source before its applied on clock source.

  • The clock sources should be enabled with delay-asymmetry value configuration measured from the network path.

  • The router supports phase asymmetry correction feature for a maximum of four BMCA clock sources.

  • A syslog message is generated for every phase correction change applied by phase correction feature.

Configuring Asymmetry Correction

Procedure
  Command or Action Purpose
Step 1

enable

Example:
Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.
Step 2

configure terminal

Example:
Router# configure terminal

Enters global configuration mode.

Step 3

ptp clock ordinary domain domain

Example:
Router(config)# ptp clock ordinary domain 0

Creates a Precision Time Protocol (PTP) clock and specifies the clock mode.

Step 4

asymmetry-compensation

Example:
Router(config-ptp-clk)# asymmetry-compensation

Enables inter-path asymmetry compensation.

Step 5

clock-port name slave

Example:
Router(config-ptp-clk)# clock-port SLAVE slave

Specifies the clocking mode of a PTP clock port and enters clock port configuration mode.

Step 6

transport ipv4 unicast interface interface-type negotiation

Example:
Router(config-ptp-port)# transport ipv4 
unicast interface Lo1 negotiation

Specifies the IP version, transmission mode, and interface that a PTP clock port uses to exchange timing packets.

Step 7

clock source source-address local-priority delay-asymmetry asymmetry-delay nanoseconds

Example:
Router(config-ptp-port)# clock source 
100.100.100.100 1 delay-asymmetry 73000 nanoseconds

Configures a connection to a PTP master device, and sets the asymmetry delay.

Step 8

clock source source-address local-priority delay-asymmetry asymmetry-delay nanoseconds

Example:
Router(config-ptp-port)# clock source 9.9.9.9 2 
delay-asymmetry 56000 nanoseconds

Configures a connection to a PTP master device, and sets the asymmetry delay.

Step 9

clock source source-address local-priority delay-asymmetry asymmetry-delay nanoseconds

Example:
Router(config-ptp-port)# clock source 5.5.5.1 3 
delay-asymmetry 89000 nanoseconds

Configures a connection to a PTP master device, and sets the asymmetry delay.

Verifying 1588v2 Phase Asymmetry Correction

To verify the 1588v2 phase asymmetry correction configuration, use the show command as shown in the example below: 

Router# show platform ptp phase_correction_details

Last Phase Correction applied : 36500 nanoseconds

Example: Configuring 1588v2 Phase Asymmetry Correction 




ptp clock ordinary domain 0
 asymmetry-compensation
 clock-port SLAVE slave
 transport ipv4 unicast interface Lo1 negotiation
 clock source 100.100.100.100 1 delay-asymmetry 73000 nanoseconds
 clock source 9.9.9.9 2 delay-asymmetry 56000 nanoseconds
 clock source 5.5.5.1 3 delay-asymmetry 89000 nanoseconds

Troubleshooting Tips

Use the following debug commands to troubleshoot the PTP configuration on the Cisco ASR 901 router:


DANGER

We suggest you do not use these debug commands without TAC supervision.

Command

Purpose

[no] debug platform ptp error

Enables debugging of internal errors.

The no form of the command disables debugging internal errors.

[no] debug platform ptp event

Displays event messages.

The no form of the command disables displaying event messages.

[no] debug platform ptp verbose

Displays verbose output.

The no form of the command disables displaying verbose output.

[no] debug platform ptp all

Debugs for error, event and verbose.

The no form of the command disables all debugging.