Table Of Contents
Configuring Synchronous Ethernet
Understanding SyncE
Reference Clocks
BITS Interface
Synchronous Ethernet and Ethernet Synchronization Messaging Channel
Configuring Synchronous Ethernet
Configuring Input Clock and Priority
Configuring Hold-off timer
Configuring Hold-over Timer
Configuring Wait-to-Restore Timer
Configuring Revertive Mode
Configuring EEC Option
Configuring BITS
Configuring BITS Input
Configuring BITS Output
Configuring Output Clock
SyncE Show Commands
SyncE Debug Commands
Configuring SyncE
Default SyncE Configuration
Configuring the Network Clock Selection
Configuring the BITS Interface
Selecting the Network Clock
Configuring Synce using ESMC and SSM
Monitoring SyncE
Configuring Synchronous Ethernet
The ME 3800X and ME 3600X switches support Synchronous Ethernet (SyncE), which is the PHY-layer frequency-synchronization solution for IEEE 802.3 links. It is an evolution of the conventional Ethernet and Ethernet + SDH and SONET-based synchronization. SyncE is used to synchronize and send clock information to remote sites on the network. Each network element along the synchronization path must support SyncE. SyncE provides only frequency synchronization, not related to time or space.
•
Understanding SyncE
•
Configuring SyncE
•
Monitoring SyncE
Understanding SyncE
SyncE provides a method to synchronize the Ethernet network by having all Ethernet ports send data based on a reference clock. All devices supporting SyncE must send and receive data in cycles of fixed size and duration. The data size depends on the Ethernet speed. The rate of transmission is 8000 cycles per second. Each device must be able to support a system timing master, which is the synchronization source. A sync port is the port on which synchronization information is received. All SyncE frames coming from the sync port are the source of synchronization for all other ports on the device.
The switch 10 Gigabit Ethernet uplink ports or BITS interface support line clock recovery, sending and receiving clock information. Downlink ports do not perform clock recovery and can only send clock signals.
The switch supports TI (1544 kilobits/s) and E1 (2048 kb/s or 2048 KHz) clock timing synchronization.
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Reference Clocks
•
BITS Interface
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Synchronous Ethernet and Ethernet Synchronization Messaging Channel
Reference Clocks
A switch comes up in a free-run state, using the internal oscillator (Stratum 3) for synchronization. If there is a valid clock reference with a set priority, the switch locks to that reference. If there is no reliable clock source available, the switch remains in free-run mode. If the current clock becomes invalid, the switch goes into holdover mode and replays the saved clock from the last source. The switch SyncE LEDs show the status of the internal clock: locked (green), free run (off), or in a holdover state (amber).
The reference clock source can be:
•
A Building Integrated Timing Supply (BITS) clock input
•
A PHY-recovered clock from uplink ports. The ME 3800X and 3600X switch supports a PHY-recovered clock only from the small form-factor pluggable (SFP+) uplink ports with 10 Gigabit SFP+ or 1000BASE-X fiber SFP modules.
All uplink and downlink ports transmit data on the same reference clock.
The switch monitors each input clock for frequency accuracy and activity. An input clock with a frequency out-of-band alarm or an activity alarm is invalid. Invalid clocks are not selected as the reference clock.
During normal operation, the reference clock is selected based on an algorithm that uses the priority rankings that you assign to the input clocks by using the network-clock input-source priority global configuration command. Priority 1 is the highest, and priority 15 is the lowest. If you try to assign the same priority to more than one clock, error message appears. Unused input clocks are given a priority value of 0, which disables the clocks and makes them unavailable for selection. The clock selection is based on signal failure, priority, and manual configuration. If you have not manually configured a reference clock, the algorithm selects the clock with the highest priority that does not experience signal failure.
With this configuration, pure priority-based mode, an intermittent failure or changes in the network topology can cause timing loops or a loss of connectivity with the clock reference. The Ethernet Synchronous Messaging Channel (ESMC) with Synchronization Status Messages (SSM) provides a way to implement quality in synchronous networks.
Reference clocks operate in revertive or nonrevertive mode, configured by using the network-clock revertive global configuration command. The reverence clocks will be in non-revertive mode by default.
•
In revertive mode, if an input clock with a higher priority than the selected reference becomes available, the higher priority reference is immediately selected.
•
In nonrevertive mode, if a new input clock with a higher priority becomes available, the higher-priority clock is selected.
•
In non revertive mode, when an input clock with a high priority present on the system becomes invalid or unavailable, a lower priority clock will be selected. However when the higher priority clock becomes available again it will not be selected.
You can use the network-clock switch privileged EXEC command to configure the input reference to be either forced or automatically selected by the selection algorithm based on the highest priority valid input clock. In revertive mode, the forced clock automatically becomes the selected reference. In nonrevertive mode, the forced clock becomes the selected reference only when the existing reference is invalidated or unavailable.
BITS Interface
The ME 3800X and ME 3600X switch supports a BITS interface through an RJ-45 connector. The connection can be used for sending and receiving T1 and E1 timing signals.
You can configure all Ethernet ports to send data referenced to the BITS recovered clock. The BITS signal is used as long as it does not have these faults:
•
loss of signal
•
out of frame
•
alarm-indication signal
•
remote alarm indication
The switch supports BITS IN and BITS OUT, and recovers and sends BITS timing, T1, E1. The switch does not support T1 or E1 data transmission. You can configure the BITS interface input and output, including line coding and line buildout (output). You can also shut down the BITS controller.
The switch supports these BITS configurations:
•
E1 Mode:
–
2048 KHz
–
Framing mode: FAS, MFAS, FASCRC4, MFASCRC4 with line coding: AMI, HDB3
•
T1 Mode:
–
Framing mode: D4 and ESF
–
Line coding: AMI, B8ZS
–
Line buildout (output): 0 to 133 feet, 133 to 266 feet, 266 to 399 feet, 399 to 533 feet, or 533 to 655 feet
Synchronous Ethernet and Ethernet Synchronization Messaging Channel
The ME3600/ME3800 switches support the following Synchronous Ethernet (SyncE) and Ethernet Synchronization Messaging Channel (ESMC) features:
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Common IOS CLI configuration
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Configuration on all ports, including BITS ports and copper ports
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Can be enabled or disabled on individual ports
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Synchronous Ethernet clock derived from user configuration
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Synchronous Status Message (SSM) on BITS interface
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Ethernet Synchronous Messaging Channel (ESMC) on all Ethernet ports
Clock selection is configured by the user based on clock priority and ESMC/SSM messages received from all sources and ports.
A Synchronous Status Message (SSM) informs the peer about the quality of the local clock source and is used to detect and avoid timing loops. SSMs are transported over the Ethernet Synchronization Messaging Channel (ESMC). All SSM information transported over Ethernet ports must be in the ESMC message format (G.8264).
The BITS port can be configured as a T1 or E1 interface.
•
For T1s, SSM messages are transported over the 4 Kbps datalink channel.
•
For E1s, SSM messages are transported over the E1 signaling channel.
Configuration
To configure synchronous ethernet in Release 15.1(2)EY
1.
Replace existing syncE configurations with the new configurations given in the "Configuring Synchronous Ethernet" section.
2.
Copy the changed configuration to startup-config
3.
Reload the switch with the 15.1(2)EY image.
Restrictions
T1 mode supports only D4 and ESF framing.
Configuring Synchronous Ethernet
The following sections show the old and new methods of configuring synchronous ethernet on the ME3600/ME3800 switches:
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Configuring Input Clock and Priority
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Configuring Hold-off timer
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Configuring Hold-over Timer
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Configuring Wait-to-Restore Timer
•
Configuring Revertive Mode
•
Configuring EEC Option
•
Configuring BITS
•
Configuring BITS Input
•
Configuring BITS Output
•
Configuring Output Clock
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SyncE Show Commands
Configuring Input Clock and Priority
Old Configuration
Switch(config)# network-clock_select 2 ?
Switch(config)# network-clock_select 2 SYNCE ?
New Configuration
Switch(config)# network-clock input-source ?
Switch(config)#network-clock input-source 1 ?
external External Interface (BITS/SSU/GPS)
interface Specify Ethernet, Sonet or ToP Interface
SynchE as Clock Source Example Configuration
Switch(config)# network-clock input-source 1 interface tenGigabitEthernet ?
<0-0> TenGigabitEthernet interface number
BITS as Clock Source Example Configuration
Switch(config)# network-clock input-source 1 external 1/0/0 e1 ?
cas E1 Channel Associated Signal Mode
crc4 E1 With CRC4 Signal Mode
fas E1 Frame Alignment Signal Mode
Note
Currently, the E1 and T1 modes cannot be configured independently.
The default values for the E1 mode are as follows:
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Framing: FAS
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Line coding: AMI
The default values for the T1 mode are as follows:
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Framing: D4
•
Line coding: AMI
•
Line build out: 0-133ft
Configuring Hold-off timer
Old Configuration
Switch(config)# network-clock_select hold-off-timeout ?
<50-10000> holdoff-val in ms, default 300 ms
New Configuration
Switch(config)# network-clock hold-off ?
<50-10000> msec (default 300 msecs)
Configuring Hold-over Timer
Old Configuration
Switch(config)# network-clock_select hold-timeout ?
<0-86400> hold-timeout-val
infinite Infinite hold-over.
New Configuration
CLI is not available.
Configuring Wait-to-Restore Timer
Old Configuration
Switch(config)# network-clock_select wait-to-restore-timeout ?
<0-720> wtr-val in seconds, default 300 seconds
New Configuration
Switch(config)# network-clock wait-to-restore ?
<0-86400> sec (default 300 seconds)
Configuring Revertive Mode
Old Configuration
Switch(config)# network-clock_select mode ?
nonrevert Specify non revertive mode.
revert Specify revertive mode.
New Configuration
Switch(config)# network-clock revertive
Switch(config)# no network-clock revertive
Configuring EEC Option
Old Configuration
Switch(config)# network-clock_select option ?
New Configuration
Switch(config)# network-clock synchronization ssm option ?
1 Synchronization networking Option I
2 Synchronization networking Option II
Switch(config)# network-clock synchronization ssm option 2 ?
GEN1 Option II Generation 1
GEN2 Option II Generation 2
Configuring BITS
Old Configuration
Switch(config)# controller BITS ?
input Configure BITS INPUT
output Configure BITS OUTPUT
shutdown Shut down BITS controller
New Configuration
Switch(config)# controller BITS ?
input Configure BITS input
output Configure BITS output
shutdown Shut down BITS controller
Configuring BITS Input
Old Configuration
controller BITS input applique ?
Switch(config)# controller BITS input applique E1 ?
2048KHz 2048 KHz clock interface
framing BITS framing options for E1
Switch(config)# controller BITS input applique E1 framing ?
Switch(config)# controller BITS input applique E1 framing fas_crc4 linecode ?
New Configuration
Same as Old Configuration.
Configuring BITS Output
Old Configuration
Switch(config)# controller BITS output applique ?
Switch(config)# controller BITS output applique T1 framing ?
Switch(config)# controller BITS output applique T1 framing d4 linecode ?
Switch(config)# $ controller BITS output applique T1 framing d4 linecode ami
line-build-out ?
133-266ft 133 ft to 266 ft
266-399ft 266 ft to 399 ft
399-533ft 399 ft to 533 ft
533-655ft 533 ft to 655 ft
New Configuration
Same as Old Configuration.
The controller BITS CLIs should be used to configure shutdown, linecode and line-build-out as these options are missing in netsync PI infrastructure CLIs. Once the netsync infrastructure CLIs implement these configuration options, the platform "controller BITS" CLIs will be deprecated.
Configuring Output Clock
Old Configuration
Switch(config)# network-clock_select output ?
output Configure BITS OUT (T4 = T0)
Switch(config)# network-clock_select output 2 SYNCE ?
New Configuration
Switch(config)# network-clock output-source ?
Tengig Clock for BITS OUT Example Configuration
Switch(config)# network-clock output-source line ?
Switch(config)# $ network-clock output-source line 10 interface tenGigabitEthernet ?
<0-0> TenGigabitEthernet interface number
System Clock for BITS OUT Example Configuration
Switch(config)# network-clock output-source system ?
Switch(config)# network-clock output-source system 10 external 1/0/0 ?
SyncE Show Commands
The following example shows how to display the SyncE network-clock information:
Switch# show network-clock synchronization ?
external External Interface (BITS/SSU/GPS)
global Display global parameters
interface Specify Ethernet or Sonet Interface
runtime Runtime Information
Switch# show network-clock synchronization detail
SyncE Debug Commands
The following example shows the network-clock (PI) debug command:
error Network clock error debugging
event Network clock event debugging
pal Network clock PAL debugging
platform Network clock platform debugging
sm Network clock state machine debugging
Configuring SyncE
SyncE limitations on copper ports:
•
To receive clock data from an ME 3600X-TS 1 Gigabit Ethernet copper SFP interface, the link partner must not be the 802.3 master port when 802.3 Clause 28 autonegotiation completes.
•
On ME3600X-FS or ME3800X switches, SyncE is not supported on 1 Gigabit Ethernet copper SFPs for the first release.
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Default SyncE Configuration
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Configuring the Network Clock Selection
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Configuring the BITS Interface
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Selecting the Network Clock
•
Configuring Synce using ESMC and SSM
Default SyncE Configuration
Synchronous Ethernet can only be configured on 10 Gigabit Ethernet interfaces.
1 Gigabit Ethernet interfaces transmit SyncE with no configuration required. No configuration is needed to send clock timing in uplink or downlink interfaces.
Configuring the Network Clock Selection
Beginning in privileged EXEC mode, follow these steps to configure the SyncE network clock.
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Command
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Purpose
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Step 1
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configure terminal
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Enter global configuration mode.
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Step 2
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network-clock input-source priority [external] [interface]
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Configure the input clock and its priority.
• For priority, the range is from 1 to 15, with 1 being the highest priority and 15 the lowest. Unused input clocks are given a priority value of 0.
• external—Select the external interface (BITS/SSU/GPS).
• interface—Select the type of interface, Ethernet, Sonet or ToP.
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Step 3
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network-clock output-source system priority external
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Configure the 10 Gigabit Ethernet ports for SYNC output:
• For priority, the range is from 1 to 15, with 1 being the highest priority and 15 the lowest.
• external—Select the external interface (BITS/SSU/GPS).
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Step 4
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network-clock revertive
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(Optional) Configure the reference switching mode to determine the action to be taken if an input clock with a higher priority than the selected reference becomes valid.
• revertive—The higher priority reference is immediately selected as the reference clock.
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Step 5
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end
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Return to privileged EXEC mode.
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Step 6
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show network-clocks
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Verify the configuration.
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Step 7
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copy running-config startup config
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(Optional) Save your entries in the switch startup configuration file.
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Enter the no network-clock priority or network-clock output-source to remove the selected priority. Enter the no network-clock revertive to select the other mode.
This example configures the BITS clock with a priority of 2 and the SyncE input port as 10 Gigabit Ethernet port 0/1 with the switching mode as nonrevertive.
Switch (config)# network-clock input-source 2 external 1/0/0 e1
Switch (config)# network-clock input-source 1 interface tenGigabitEthernet
Switch (config)# network-clock revertive
Configuring the BITS Interface
Beginning in privileged EXEC mode, follow these steps to configure the BITS interface. The Ethernet Equipment Clock (EEC) mode of operation is based on the area of deployment.
| |
Command
|
Purpose
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Step 1
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configure terminal
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Enter global configuration mode.
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Step 2
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network-clock synchronization ssm option {option1 | option2}
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Configure the EEC option.:
• option1—Select E1 as the input clock rate.
• option2—Select T1 as the input clock rate
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Step 3
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controller BITS input applique E1 {2048KHz | framing option linecode {ami | hdb3}
or
controller BITS input applique T1 framing {d4 | esf} linecode {ami | b8zs}
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(Optional) Configure the controller BITS input framing and coding options.
For E1 input:
• 2048KHz—Select 2048 KHz input.
• framing option—Select one of these options:
– fas_crc4—FASCRC4
– fas_nocrc—FAS
– mfas_crc4—MFASCRC4
– mfas_nocre—MFAS
For T1 input:
• d4 linecode—D4
• esf linecode—Extended superframe
• linecode ami—AMI encoding
• linecode b8zs—B8ZS encoding
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Step 4
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controller BITS output applique E1 {2048KHz | framing options} linecode {ami | hdb3}
or
controller BITS output applique T1 framing {d4 | esf} linecode {ami | b8zs} line-build-out length
|
(Optional) Configure the controller BITS output framing and coding options.
For E1 output:
• 2048KHz—Select 2048 KHz input.
• framing—Select one of these options:
– fas_crc4—FASCRC4
– fas_nocrc—FAS
– mfas_crc4—MFASCRC4
– mfas_nocre—MFAS
For T1 framing output:
• d4 linecode—D4
• esf linecode—Extended superframe
• linecode ami—AMI encoding
• linecode b8zs—B8ZS encoding
• line-build-out length—Select a line length:
– 0-133ft
– 133-266ft
– 266-399ft
– 399-533ft
– 533-655ft
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Step 5
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controller BITS shutdown
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Shut down the BITS controller.
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Step 6
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end
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Return to privileged EXEC mode.
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Step 7
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show controller BITS
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Verify the configuration.
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Step 8
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copy running-config startup config
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(Optional) Save your entries in the switch startup configuration file.
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Enter the no network-clock synchronization ssm option option1 or the network-clock synchronization ssm option option2 to select the other option. mode with the default E1 or T1 values.
Use the no form of each command to remove the configuration or return to the default.
This example configures EEC as T1 with ESF framing, B8ZS line coding, and 1 to 133 foot.line buildout. Switch (config)# network-clock synchronization ssm option option2
Switch (config)# controller BITS input applique T1 framing esf linecode b8zs
Switch (config)# controller BITS output applique T1 framing esf linecode b8zs
line-build0-out 0-133ft
Switch# show controllers BITS
Line Coding is B8ZS(Rx), B8ZS(Tx)
Framing is ESF(Rx), ESF(Tx)
Line Build Out is 0-133ft
Selecting the Network Clock
You can force selection of a particular network clock or select automatic clock selection where the switch uses the selection algorithm based on the priority and the validity of the input.
Beginning in privileged EXEC mode, use this step to set the SyncE network clock.
| |
Command
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Purpose
|
Step 1
|
network-clock {clear | set | switch}
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Select one of these options:
• clear—Use to clear network clock synchronization
• set—Set network clock synchronization
• switch—Switch selected synchronization source.
If the switch is in nonrevertive mode, the clock input does not change unless the current clock becomes invalid.
|
Step 2
|
show network-clocks
|
Verify the configuration.
|
Step 3
|
copy running-config startup config
|
(Optional) Save your entries in the switch startup configuration file.
|
Configuring Synce using ESMC and SSM
To enable ESMC process use the following steps:
| |
Command
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Purpose
|
Step 1
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enable
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Enter privileged EXEC mode.
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Step 2
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configure terminal
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Enter global configuration mode.
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Step 3
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esmc process
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Enables ESMC process.
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To configure the interface to send or receive a particular clock use the following steps:
| |
Command
|
Purpose
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Step 1
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enable
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Enter privileged EXEC mode.
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Step 2
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configure terminal
|
Enter global configuration mode.
|
Step 3
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interface interface-id
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Enter the interface ID, and enter interface configuration mode.
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Step 4
|
network-clock source quality-level value {tx | rx}
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Provides the forced QL value to the local clock selection process.
|
To configure BITS port to send or receive a particular-clock use the following steps:
| |
Command
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Purpose
|
Step 1
|
enable
|
Enter privileged EXEC mode.
|
Step 2
|
configure terminal
|
Enter global configuration mode.
|
Step 3
|
network-clock quality-level {tx | rx}value external port/slot
|
Forces the QL value for the line or external timing input and output
|
Monitoring SyncE
Use these privileged EXEC commands to view SyncE configuration on a switch:
•
show controller BITS
Switch# show controller BITS
Line Coding is B8ZS(Rx), B8ZS(Tx)
Framing is ESF(Rx), ESF(Tx)
Line Build Out is 0-133ft
•
show network-clock synchronization
Switch# show network-clock synchronization detail
Symbols: En - Enable, Dis - Disable, Adis - Admin Disable
* - Synchronization source selected
# - Synchronization source force selected
& - Synchronization source manually switched
Automatic selection process : Enable
Equipment Clock : 1544 (EEC-Option2)
T0 : TenGigabitEthernet0/2
Hold-off (global) : 300 ms
Wait-to-restore (global) : 300 sec
Number of synchronization sources: 2
Squelch Threshold: QL-ST3
sm(netsync NETCLK_QL_ENABLE), running yes, state 1A
Last transition recorded: (ql_mode_enable)-> 1A (begin)-> 1A (src_added)-> 1A
(src_added)-> 1A (ql_change)-> 1A (ql_change)-> 1A (set_lo)-> 1A (clear_lo)-> 1A
Interface SigType Mode/QL Prio QL_IN ESMC Tx ESMC Rx
Internal NA NA/Dis 251 QL-ST3 NA NA
Te0/1 NA Sync/En 1 QL-FAILED - -
*Te0/2 NA Sync/En 2 QL-PRS - -
External Interface SigType Input Prio Squelch AIS
External 1/0/0 T1 ESF Internal 2 FALSE FALSE
---------------------------------------------
Local Interface: Internal
QL Transmit Configured: -
SNMP input source index: 1
SNMP parent list index: 0
Mode: Synchronous(Ql-enabled)
QL Receive Overrided: QL-FAILED
QL Transmit Configured: -
SNMP input source index: 2
SNMP parent list index: 0
Mode: Synchronous(Ql-enabled)
QL Transmit Configured: -
SNMP input source index: 3
SNMP parent list index: 0
External 1/0/0 t1 esf's Input:
Local Interface: Internal
QL Transmit Configured: -
SNMP input source index: 1
SNMP parent list index: 1
•
show esmc
Interface: GigabitEthernet0/0/0
Administrative configurations:
ESMC Information rate : 1 packet/second