Huawei Quidway S9300

Figure 5-2 Process of setting up and maintaining single-hop PWE3
PE1
PE2
Loopback1
1.1.1.1/32
Loopback1
2.2.2.2/32
mpls l2vc 2.2.2.2 101
mpls l2vc 1.1.1.1 101
parameter match,VC up
parameter match,VC up
AC/Tunnel state changed
AC/Tunnel state changed
Request
Mapping
Mapping
Notification
Based on the Martini mode, the dynamic PW adds the optional status parameter in the Mapping
message and supports the Notification message.
When a network is unstable, Notification messages can be used to notify the status so that the
number of packets to be exchanged is reduced. For example, if an AC link flapping occurs on a
PE, the PE sends a Notification message to notify the peer of the local AC status. After receiving
the message, the peer does not tear down the VC. In Martini mode, however, if an AC flapping
occurs on a PE, the PE sends Withdraw messages continuously; therefore, PWs are set up and
deleted repeatedly.
NOTE
In PWE3, the PW status can be negotiated by exchanging Notification messages and the labels can be
deleted by sending Withdraw messages. When setting up a PW, the two ends can negotiate the mode to be
used.
Process of tearing down a dynamic PW
Figure 5-3 shows the process of packet interaction during the dismantlement of a dynamic PW.
Figure 5-3 Process of tearing down single-hop PWE3
PE1 PE2
Loopback1
1.1.1.1/32
Loopback1
2.2.2.2/32
mpls l2vc 2.2.2.2 101 mpls l2vc 1.1.1.1 101
VC Deletion
Withdraw
Release
VC Deletion
Withdraw
Quidway S9300 Terabit Routing Switch
Configuration Guide - VPN 5 PWE3 Configuration
Issue 03 (2009-08-20) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
5-5