cc exp

Function

The cc exp command sets a priority for continuity check messages (CCMs).

The undo cc exp command restores the default priority.

The default priority of CCMs is 7.

Format

cc exp exp-value

undo cc exp

Parameters

Parameter	Description	Value
exp-value	Sets a priority for CCMs.	The value is an integer ranging from 0 to 7. A larger value indicates a higher priority. The default value is 7.

Parameter

Description

Value

exp-value

Sets a priority for CCMs.

The value is an integer ranging from 0 to 7. A larger value indicates a higher priority. The default value is 7.

Views

Maintenance entity group view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
tpoam	write

Usage Guidelines

Usage Scenario

CC monitors connectivity between two MEPs in a MEG. The cc interval command can be run on a MEP to set an interval at which CCMs are sent. A MEP sends CCMs to its remote MEP (RMEP) at a specified interval. If the RMEP does not receive CCMs within a period of 3.5 times if the specified interval, the RMEP considers that the connectivity between the MEPs has errors, reports an alarm, and enters the Down state. After that, automatic protection switching (APS) is triggered on both MEPs. After receiving a CCM from the MEP, the RMEP will clear the alarm and exit from the Down state.

If the MPLS-TP network is severely congested and the priority of CCMs is low, CCMs fail to be sent. If the peer device does not receive any CCMs within a period of 3.5 times the specified interval, it incorrectly considers the link failed and triggers APS. The cc exp command is required to set a proper priority for CCMs after CC is enabled.

Prerequisites

The ME of the MEG has been bound to a tunnel.

Example

# Set the priority for CCMs to 6 in a MEG named test.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] mpls te
[*HUAWEI-mpls] quit
[*HUAWEI] mpls l2vpn
[*HUAWEI-l2vpn] quit
[*HUAWEI] interface GigabitEthernet 0/1/0.1
[*HUAWEI-GigabitEthernet0/1/0.1] vlan-type dot1q 1
[*HUAWEI-GigabitEthernet0/1/0.1] mpls static-l2vc destination 4.4.4.4 400 transmit-vpn-label 100 receive-vpn-label 200
[*HUAWEI-GigabitEthernet0/1/0.1] quit
[*HUAWEI] mpls-tp meg test
[*HUAWEI-mpls-tp-meg-test] me l2vc peer-ip 4.4.4.4 vc-id 400 vc-type vlan mep-id 1 remote-mep-id 2
[*HUAWEI-mpls-tp-meg-test] cc exp 6