Cisco ASR 903 Router Chassis Software Configuration Guide
Configuring Clocking and Timing
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Configuring Clocking and Timing

Table Of Contents

Configuring Clocking and Timing

Clocking and Timing Overview

Timing Port Specifications

BITS Framing Support

Clocking and Timing Restrictions

Configuring Clocking and Timing

Configuring Input Clocking

Configuring Output Clocking

Configuring Time-of-Day Messages

Configuring Input Time-of-Day Messages

Configuring Output Time-of-Day Messages

Synchronous Ethernet ESMC and SSM

Configuring Calendar Updates

Sample Configurations


Configuring Clocking and Timing


This chapter explains how to configure timing ports on the Cisco ASR 903 Series Router RSP module.

Clocking and Timing Overview

The Cisco ASR 903 Series Router has the following timing ports:

1PPS Input/Output

10MHz Input/Output

ToD

BITS

You can use the timing ports on the Cisco ASR 903 Series Router to do the following:

Provide or receive 1PPS messages

Provide or receive time of day messages

Provide output clocking at 10Mhz, 2.048Mhz, and 1.544Mhz

Receive input clocking at 10Mhz, 2.048Mhz, and 1.544Mhz


Note Timing input and output is handled by the active RSP.


The following sections describe how to configure clocking and timing features on the Cisco ASR 903 Series Router.

Timing Port Specifications

The following sections provide specifications for the timing ports on the Cisco ASR 903 Series Router.

BITS Framing Support

Table 9-1 lists the supported framing modes for a BITS port on a Cisco ASR 903 Series Router.

Table 9-1 Framing Modes for a BITS Port on a Cisco ASR 903 Series Router

BITS or SSU Port Support Matrix
Framing Modes Supported
SSM or QL Support
Tx Port
Rx Port

T1

T1 ESF

Yes

Yes

Yes

T1

T1 SF

No

Yes

Yes

E1

E1 CRC4

Yes

Yes

Yes

E1

E1 FAS

No

Yes

Yes

2048 kHz

2048 kHz

No

Yes

Yes


The BITS port behaves similarly to the T1/E1 ports provided on the T1/E1 interface module; for more information about configuring T1/E1 interfaces, see Chapter 8 "Configuring T1/E1 Interfaces."

Clocking and Timing Restrictions

The following clocking and timing restrictions apply to the Cisco ASR 903 Series Router:

You can configure only a single clocking input source within each group of 8 ports (0-7 and 8-15) on the T1/E1 interface module using the network-clock input-source command.

PTP functionality is restricted by license type. The following table summarizes the PTP functionality available by license type:

License
PTP Support

Metro Services

Not supported

Metro IP Service

Ordinary Slave Clock

Metro Aggregation Service

Ordinary Slave Clock

Metro IP Service + IEEE 1588-2008 BC/MC

All PTP functionality including boundary and master clock

Metro Aggregation Service + IEEE 1588-2008 BC/MC

All PTP functionality including boundary and master clock



Note If you install the IEEE 1588-2008 BC/MC license, you must reload the router to use the full PTP functionality.


Configuring Clocking and Timing

The following sections describe how to configure clocking and timing features on the Cisco ASR 903 Series Router:

Configuring Input Clocking

Configuring Output Clocking

Configuring Time-of-Day Messages

Synchronous Ethernet ESMC and SSM

Configuring Calendar Updates

Configuring Input Clocking

If you want to configure input network clocking, complete the following steps:

SUMMARY STEPS

1. enable

2. configure terminal

3. interface gigabitethernet slot/subslot/port (gigabit ethernet interface clocking only)

4. synchronous mode (gigabit ethernet interface clocking only)

5. exit (gigabit ethernet interface clocking only)

6. network-clock synchronization automatic

7. network-clock input-source priority {interface interface_name slot/card/port | ptp domain domain_num | {external {R0 | R1 [ { t1 {sf | esf } linecode {ami | b8zs} line-build-out num} | e1 [crc4 | fas] [125ohm | 75ohm] linecode [hdb3 | ami] } | 2m | 10m] }}

8. exit

 
Command
Purpose

Step 1 

configure terminal

Example:

Router# configure terminal

Enter configuration mode.

Step 2 

interface gigabitethernet slot/subslot/port

Example:

Router# interface gigabitethernet 0/0/1

Enter interface configuration mode.

Note This step only applies if you are configuring input timing on a gigabit Ethernet interface.

Step 3 

synchronous mode

Example:

Router(config-if)# synchronous mode

Set the port in synchronous mode.

Note This step only applies if you are configuring input timing on a gigabit Ethernet interface.

Step 4 

Router(config-if)# exit

Exit interface configuration mode.

Note This step only applies if you are configuring input timing on a gigabit Ethernet interface.

Step 5 

network-clock synchronization automatic

Example:

Router(config)# [no] 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 6 

network-clock input-source priority {interface interface_name slot/card/port | ptp domain domain_num | {external {R0 | R1 [ { t1 {sf | esf } linecode {ami | b8zs} line-build-out num} | e1 [crc4 | fas] [125ohm | 75ohm] linecode [hdb3 | ami] } | 2m | 10m] }}

Example:
Router(config)# network-clock 
input-source 2 external r0 e1 crc4 
120ohms linecode ami

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 or 10 MHz BITS port signal. Use the R0 or R1 keyword to specify the RSP.

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.

You can also use the framing argument to specify a T1 or E1 framing type.

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.

Note You can use R0 or R1 to specify the active RSP slot.

Step 7 

end

Example:

Router(config)# end

Exit configuration mode.

Configuring Output Clocking

If you want to configure output network clocking, complete the following steps:

SUMMARY STEPS

1. enable

2. configure terminal

3. network-clock synchronization automatic

4. network-clock output-source system priority {interface interface_name slot/card/port | ptp domain domain_num | {external {R0 | R1 [ { t1 {sf | esf } linecode {ami | b8zs} line-build-out num} | e1 [crc4 | fas] [125ohm | 75ohm] linecode [hdb3 | ami] } | 10m] }}

5. exit

 
Command
Purpose

Step 1 

Router# configure terminal

Enter configuration mode.

Step 2 

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 3 

network-clock output-source system priority {interface interface_name slot/card/port | ptp domain domain_num | {external {R0 | R1 [ { t1 {sf | esf } linecode {ami | b8zs} line-build-out num} | e1 [crc4 | fas] [125ohm | 75ohm] linecode [hdb3 | ami] } | 10m] }}

Example:

Router(config)# network-clock output-source system 2 R0 2m

Configures the router to transmit the system clock to external device using timing output interfaces.

Note You can use R0 or R1 to specify the active RSP slot.

Step 4 

Router(config)# end

Exit configuration mode.

Configuring Time-of-Day Messages

The Cisco ASR 903 Series Router can exchange time-of-day and 1PPS input with an external device such as a GPS receiver using the ToD and 1PPS input and output interfaces on the router.


Caution This feature is not currently supported.

The following sections describe how to configure time-of-day messages on the Cisco ASR 903 Series Router:

Configuring Input Time-of-Day Messages

Configuring Output Time-of-Day Messages

Configuring Input Time-of-Day Messages

Use the following steps to configure input time-of-day messages:


Note You can configure ToD input only on a PTP master clock port.


SUMMARY STEPS

1. enable

2. configure terminal

3. clock domain domain

4. clock-port name master

5. transport ipv4 {unicast | multicast | multicast-mix} interface interface-type interface-number [negotiation]

6. exit

7. tod {R0 | R1} {iso8601 | ubx | nmea | cisco | ntp} [delay delay-amount]

8. input [1pps] {R0 | R1}

9. end

 
Command
Purpose

Step 1 

Router# configure terminal

Enters configuration mode.

Step 2 

ptp clock domain domain

Example:

Router(config)# ptp clock domain domain

Creates a Precision Time Protocol clock and specify the clock mode.

Note Input ToD messages are not supported on transparent or boundary clocks.

Step 3 

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

Specifies the clocking mode of a Precision Time Protocol clock port and enters clock port configuration mode.

Note Input ToD messages are only supported on master clock ports.

Step 4 

Router(config-ptp-port)# transport ipv4 {unicast | multicast | multicast-mix} interface interface-type interface-number [negotiation]

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


Caution The multicast and multicast-mix modes are not currently supported.

Step 5 

Router(config-ptp-port)# exit

Exits PTP clock port configuration mode.

Step 6 

Router(config-ptp-clk)# tod {R0 | R1} {iso8601 | ubx | nmea | cisco | ntp} [delay delay-amount]

Configures the time of day message format used by the 1PPS or BITS interface.

Step 7 

Router(config-ptp-clk)# input [1pps] {R0 | R1}

Enables Precision Time Protocol input clocking using a 1.544Mhz, 2.048Mhz, or 10Mhz timing interface or phase using the 1PPS or RS-422 interface.

Use R0 or R1 to specify the active RSP slot.

Step 8 

Router(config)# end

Exit configuration mode.

Configuring Output Time-of-Day Messages

Use the following steps to configure output time-of-day messages:


Note Output ToD messages are only supported on slave clock ports.


SUMMARY STEPS

1. enable

2. configure terminal

3. ptp clock domain domain

4. clock-port name slave

5. transport ipv4 {unicast | multicast | multicast-mix} interface interface-type interface-number [negotiation]

6. clock source source-address

7. exit

8. tod {R0 | R1} {iso8601 | ubx | nmea | cisco | ntp} [delay delay-amount]

9. output 1pps {R0 | R1} [offset offset-value [negative]] [pulse-width pulse-amount {ns | us | ms}]

10. end

 
Command
Purpose

Step 1 

Router# configure terminal

Enter configuration mode.

Step 2 

ptp clock domain domain

Example:

Router(config)# ptp clock ordinary domain 1

Creates a Precision Time Protocol clock and specify the clock mode.

Step 3 

clock-port name slave

Example:

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

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

Note Output ToD messages are only supported on slave clock ports.

Step 4 

transport ipv4 {unicast | multicast | multicast-mix} interface interface-type interface-number [negotiation]

Example:

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

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

Step 5 

clock source source-address

Example:

Router(config-ptp-port)# clock source 10.1.1.1

Configures a connection to a Precision Time Protocol master device.

Step 6 

Router(config-ptp-port)# exit

Exits PTP clock port configuration mode.

Step 7 

tod {R0 | R1} {iso8601 | ubx | nmea | cisco | ntp} [delay delay-amount]

Example:

Router(config-ptp-clk)# tod R0 ntp

Configures the time of day message format used by the 1PPS or BITS interface.

Step 8 

output 1pps {R0 | R1} [offset offset-value [negative]] [pulse-width pulse-amount {ns | us | ms}]

Example:

Router(config-ptp-clk)# output 1pps R0

Enables out put of time of day messages using a 1PPS interface.

Use R0 or R1 to specify the active RSP slot.

Step 9 

Router(config)# end

Exit configuration mode.

Synchronous Ethernet ESMC and SSM

The Cisco ASR 903 Series Router supports Ethernet Synchronization Message Channel (ESMC) and Synchronization Status Message (SSM) to provide clock synchronization on Synchronous Ethernet. For more information about Ethernet ESMC and SSM, see Chapter 10 "Configuring Synchronous Ethernet ESMC and SSM."

Configuring Calendar Updates

To configure the router to periodically update the system calendar with PTP clock time, use the ptp update-calendar command.

Rounter(config)# ptp update-calendar
 
   

Note For more information about configuring clocking and timing see the Carrier Ethernet Configuration Guide, Cisco IOS XE Release 3S.


Sample Configurations

This section contains sample configurations for clocking features on the Cisco ASR 903 Series Router.


Note This section contains partial router configurations intended to demonstrate a specific feature.


Master Clock

network-clock input-source 1 external R010m 
ptp clock ordinary domain 1
tod R0 ntp 
input 1pps R0 
clock-port  master master 
transport ipv4 unicast interface loopback 0 negotiation
 
   

Slave clock

ptp clock ordinary domain 1
tod R0 ntp 
output 1pps R0 
clock-port SLA slave
transport ipv4 unicast interface loopback 0 negotiation
clock source 10.1.1.1
 
   

Boundary clock

ptp clock boundary domain 1
clock-port SLA slave
transport ipv4 unicast interface loopback 0 negotiation
clock source 10.1.1.1
clock-port  master master 
transport ipv4 unicast interface loopback 1 negotiation