Huawei S6700 Series Configuration Manual page 433

S6700 Series Ethernet Switches
Configuration Guide - IP Routing
Route loops may easily occur in this network. For example, when Client1 receives an updated
route from an EBGP peer, it uses IBGP to advertise this route to RR1 and RR2. Then the
following problems will happen in the same time:
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As a result, a route loop occurs between RR1 and RR2.
To address this problem, configure all switches on the network shown in
same cluster and assign them the same cluster ID. After the configuration is complete, if Client1
receives an updated route from an EBGP peer, it uses IBGP to advertise this route to RR1 and
RR2.
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Perform the following steps on each switch that is running BGP:
Procedure
Step 1 Run:
system-view
The system view is displayed.
Step 2 Run:
bgp as-number
The BGP view is displayed.
Step 3 Run:
ipv4-family unicast
The IPv4 unicast address family view is displayed.
Step 4 Run:
reflector cluster-id cluster-id
A cluster ID is configured.
If a cluster has multiple RRs, use this command to set the same cluster-id for these RRs to prevent
route loops.
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Issue 01 (2012-03-15)
RR1 advertises it to its clients and non-client (RR2),
RR2 advertises it to its clients and non-client (RR1).
After receiving this route, RR1 reflects it to its clients and RR2 and adds the local cluster
ID to the front of the cluster list.
After receiving the route reflected from RR1, RR2 checks the cluster list. After finding that
the local cluster ID is already on the cluster list, RR2 discards the route.
NOTE
Using a cluster list prevents route loops between RRs within an AS.
NOTE
To ensure that a client can learn the routes reflected by an RR, the Cluster ID configured on the RR must
be different from the Cluster ID of the client (By default, the client uses its Router ID as the cluster ID). If
the Cluster ID is the same as the Cluster ID of the client, the client discards received routes.
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7 BGP Configuration
Figure 7-1 into the
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