Huawei Quidway NetEngine80E Configuration Manual page 49

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
Figure 1-3 Networking of a direct route responding to L3VE interface status changes after a
delay
NodeB
AGG1 is used as the master device in the preceding figure. In normal cases, RSGs select routes
advertised by AGG1 and traffic travels along Link A. If AGG1 or the CSG-AGG1 link fails,
traffic is switched over to Link B. After AGG1 or the CSG-AGG1 link recovers, the L3VE
interface on AGG1 goes from Down to Up, and AGG1 immediately generates a direct route
destined for the CSG and advertises the route to RSGs. Downstream traffic is then switched over
to Link A. However, AGG1 has not learned the MAC addresses of the base stations yet, so
downstream traffic will be lost.
After you configure a cost for a direct route and allow the direct route to restore its default cost
0 after a delay, when the L3VE interface on AGG1 goes from Down to Up, the cost of the direct
route between the CSG and AGG1 is modified to the configured cost. In this case, RSGs do not
select routes advertised by AGG1 and downstream traffic still travels along Link B. After the
configured delay expires, the cost of the direct route to the CSG is restored to the default value
0. Then, RSGs select routes advertised by AGG1 and downstream traffic is switched over to
Link A. At this time, AGG1 has learned the MAC addresses of the base stations, and downstream
traffic loss will be reduced.
Pre-configuration Tasks
Before you configure an IPv4 direct route to respond to L3VE interface status changes after a
delay, complete the following task:
l
Data Preparation
To configure an IPv4 direct route to respond to L3VE interface status changes after a delay, you
need the following data.
Issue 02 (2014-09-30)
CSG
L2VPN
Configuring link-layer protocol parameters and IP addresses for interfaces to ensure that
the link layer protocol of each interface is Up
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AGG1
RSG1
Link A
Link B
AGG2 RSG2
L3VPN
1 IP Routing Basic Configuration
RNC
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