cc seq-number

Function

The cc seq-number command enables the sequence number function in a PW template.

The undo cc seq-number command disables the sequence number function in a PW template.

By default, the sequence number function is disabled.

Format

cc seq-number

undo cc seq-number

Parameters

None

Views

PW template view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
l2vpn	write

Usage Guidelines

Usage Scenario

In PW load balancing scenarios, PW packets may arrive at a device out of order. To prevent this problem, run the cc seq-number command to enable the sequence number function. After the sequence number function is enabled, the local PE sends PW packets carrying the Sequence Number field. Each time a PW packet is sent, the Sequence Number field value increases by 1 in sequence. After the remote PE receives PW packets, it checks the Sequence Number field in the packets. If the device receives a packet that has a smaller Sequence Number field value than that in the packet previously received, the device discards the packet with a smaller Sequence Number field value. In addition, the device calculates the number of packets discarded because they arrive out of order. If the number of packets discarded in a period of time exceeds the alarm threshold, the system generates an alarm so that the network administrator can take measures.

Prerequisites

The control word function has been enabled using the control-word command.

Follow-up Procedure

Run the reset pw command for the new PW template attributes to take effect.

Precautions

The cc seq-number command takes effect only on interfaces that carry ATM services.
If the mpls l2vc or mpls static-l2vc command with the cc seq-number parameter has been run, and the cc seq-number command has also been run in the PW template view to enable the sequence number function, the mpls l2vc or mpls static-l2vc command configuration takes effect.

Example

# Enable the sequence number function in the PW template pt.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] quit
[*HUAWEI] mpls l2vpn
[*HUAWEI-l2vpn] quit
[*HUAWEI] pw-template pt
[*HUAWEI-template-pt] control-word
[*HUAWEI-template-pt] cc seq-number