BGP Features
This section describes the following BGP features supported by ExtremeWare XOS:
Route Reflectors on page 569
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Route Confederations on page 571
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Route Aggregation on page 574
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Using the Loopback Interface on page 574
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BGP Peer Groups on page 574
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BGP Route Flap Dampening on page 575
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BGP Route Selection on page 577
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Route Redistribution on page 577
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BGP Static Network on page 578
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Route Reflectors
Another way to overcome the difficulties of creating a fully meshed AS is to use route reflectors. Route
reflectors allow a single router to serve as a central routing point for the AS.
A cluster is formed by the route reflector and its client routers. Peer routers that are not part of the
cluster must be fully meshed according to the rules of BGP.
A BGP cluster, including the route reflector and its clients, is shown in
Figure 76: Route reflectors
1.1.1.1
Non-client
The topology shown in
Figure 76
using route reflectors.
In this example, although the BGP speakers 3.3.3.3 and 4.4.4.4 do not have a direct BGP peering session
between them, these speakers still receive routes from each other indirectly through 2.2.2.2. The router
2.2.2.2 is called a route reflector and is responsible for reflecting routes between its clients. Routes
ExtremeWare XOS 11.3 Concepts Guide
AS 100
10.0.0.1
2.2.2.2
10.0.0.2
Route Reflector
minimizes the number of BGP peering sessions required in an AS by
Figure
76.
20.0.0.1
Client
20.0.0.2
30.0.0.2
30.0.0.1
Client
Cluster
BGP Features
3.3.3.3
4.4.4.4
EX_042
569