Establishing The Configuration Task - Huawei Quidway S9300 Configuration Manual

Quidway S9300 Terabit Routing Switch
Configuration Guide - VPN

4.9.1 Establishing the Configuration Task

Applicable Environment
VLL FRR supported by the S9300 is mainly used in the following networking modes:
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After the VLL 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 VPN FRR, complete the following tasks:
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Issue 03 (2009-08-20)
Asymmetrically connected CEs
The CE on one end of the VC accesses the PE of higher reliability through a single reliable
link. The CE on the other end is dual-homed to the PE of lower reliability. Thus, two
communication paths exist between the CEs on the two ends of the VC. The path of higher
reliability functions as the master path, and the path with the lower reliability functions as
the backup path.
NOTE
For asymmetrically connected CEs, the primary and secondary IP addresses need to be configured on the
interface connecting the CE to the PE through a single link. When the master path is available, the CE uses
the primary IP address to communicate with the remote CE. When a fault occurs on the master path, the
local CE communicates with the remote CE by using the secondary IP address.
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 a PW on each of the master path and backup path for the networking where
CEs are symmetrically dual-homed to PEs (The types of PWs on the master path and backup
path may be different.)
Configuring CEs to exchange routing information by using routing protocols or static routes
NOTE
To configure a Martini VLL or PWE3, you must use the PW template to configure a PW, enable the control
word in the PW template, and use BFD to perform Virtual Circuit Connectivity Verification (VCCV).
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:
A permanent switching policy cannot be configured.
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The local CE has two equal-cost and direct routes to the remote CE. The destination addresses and next
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hops of the two routes are the same. Actually, the route that passes through the backup PW is invalid.
If CEs exchange routing information by using routing protocols, you need to modify the cost or metric
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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.
If CEs use static routes to exchange routing information, you need to modify the preference of the
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backup route to be lower than that of the primary route (the greater the value, the lower the preference)
by using the ip route-static dest-ip-address mask out-interface preference preference-value
command.
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4 VLL Configuration
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