Design Reference

Table Of Contents
Figure 27: BGP and edge aggregation
BGP and ISP segmentation
You can use the platform as a peering point between different regions or ASs that belong to
the same ISP. In such cases, you can define a region as an OSPF area, an AS, or a part of
an AS.
You can divide the AS into multiple regions that each run different IGPs. Interconnect regions
logically by using a full IBGP mesh. Each region then injects its IGP routes into IBGP and also
injects a default route inside the region. For destinations that do not belong to the region, each
region defaults to the BGP border router.
Use the community parameter to differentiate between regions. To provide Internet
connectivity, this scenario requires you to make your Internet connections part of the central
IBGP mesh (see the following figure).
Border Gateway Protocol
Network Design Reference for Avaya VSP 4000 February 2014 69