Cisco Systems A9014CFD Configuring Esmc in Global Configuration Mode, QL-disabled mode, 22-8

Chapter 22 Configuring Clocking

Configuring Network Clock for Cisco ASR 901 Router

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:

SUMMARY STEPS

1.enable

2.configure terminal

3.network-clock synchronization mode ql-enabled

4.esmc process

5.network-clock quality-level {tx rx} value {interface interface-nameslot/sub-slot/portexternal slot/sub-slot/portgps slot/sub-slotcontroller slot/sub-slot/port}

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
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