Configuring Primary And Backup Pws - Huawei quidway s7700 Configuration Manual

Quidway S7700 Smart Routing Switch
Configuration Guide - VPN
After the PW FRR is configured, L2VPN traffic is rapidly switched to the backup path when a
fault occurs on the master path. After the fault on the master path is rectified, the L2VPN traffic
is switched back to the master path according to the revertive switchover policy.
Pre-configuration Tasks
Before configuring PW FRR, complete the following tasks:
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Data Preparation
To configure PW FRR, you need the following data.
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6.10.2 Configuring Primary and Backup PWs

In the networking where CEs are asymmetrically connected to PEs, you need to configure
primary and backup PWs.
Context
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Issue 01 (2011-07-15)
Configuring a PW on each of the master path and backup path for the networking where
CEs are asymmetrically connected to PEs (The types of PWs on the master path and backup
path must be the same.)
Configuring CEs to exchange routing information by using routing protocols or static routes
NOTE
In the networking where CEs are asymmetrically connected to PEs, the backup PW cannot transmit data
when the master path and backup path work normally. If the AC interface of the backup PW borrows the
IP address of the AC interface of the master PW, the following situations occur:
l A permanent non-revertive policy cannot be configured.
l The local CE has two equal-cost and direct routes to the remote CE. The destination addresses and next
hops of the two routes are the same. Actually, the route that passes through the backup PW is invalid.
l If CEs exchange routing information by using routing protocols, you need to modify the cost or metric
of the AC interface of the backup path to be greater than that of the AC interface of the master path.
The local CE cannot communicate with the peer CE, but can communicate with other user devices.
l If the AC link is an Ethernet link, the function of BFD for static routes need also be configured on CEs.
Data
Type and number of the interface connected to the CE
Destination address and VC ID of the L2VC
(Optional) Local and remote identifiers of the BFD session
(Optional) Traffic revertive switching delay after fault recovery and fault recovery
notification delay (by default, the traffic revertive switching delay is 30 seconds and
the fault recovery notification delay is 10 seconds.)
In the networking where CEs are symmetrically dual-homed to PEs, you need to configure
one PW for both the primary and backup paths. The primary and backup paths can be
configured with different types of PWs.
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