Specifications

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Cisco Nexus 3000 Series NX-OS Unicast Routing Configuration Guide, Release 5.0(3)U2(2)
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Chapter 6 Configuring Advanced BGP
Information About Advanced BGP
Figure 6-1 iBGP Network
iBGP networks are fully meshed. Each iBGP peer has a direct connection to all other iBGP peers to
prevent network loops.
Note You should configure a separate interior gateway protocol in the iBGP network.
This section includes the following topics:
• AS Confederations, page 6-4
• Route Reflector, page 6-5
AS Confederations
A fully meshed iBGP network becomes complex as the number of iBGP peers grows. You can reduce
the iBGP mesh by dividing the autonomous system into multiple subautonomous systems and grouping
them into a single confederation. A confederation is a group of iBGP peers that use the same autonomous
system number to communicate to external networks. Each subautonomous system is fully meshed
within itself and has a few connections to other subautonomous systems in the same confederation.
Figure 6-2 shows the BGP network from Figure 6-1, split into two subautonomous systems and one
confederation.
Figure 6-2 AS Confederation
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