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Cisco® BGP-4 Command and Configuration Handbook (CCIE Professional Development) by William R. Parkhurst Ph.D.

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8-27. neighbor {ip-address | peer-group-name} route-reflector-client

Syntax Description:

  • ip-address— Neighbor's IP address.

  • peer-group-name— Name of the peer group. See section 8-19.

Purpose: IBGP neighbors do not propagate routing information learned from one IBGP neighbor to another IBGP neighbor. Therefore, if you are running IBGP, every IBGP speaker must have a connection to every other IBGP speaker in the AS. This becomes a scaling problem as the number of IBGP speakers increases. The number of IBGP connections for n speakers is (n(n-1))/2. Table 8-1 lists the number of connections needed for 2 to 10 IBGP speakers.

Table 8-1. IBGP Connections Needed for a Full Mesh
Number of IBGP Speakers Number of Connections
2 1
3 3
4 6
5 10
6 15
7 21

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