Issues When Redundancy Exists Between eBGP Neighbors

In many cases, a single Layer 3 path exists between eBGP neighbors. For example, a single T1, or single T3, or maybe a single MetroE Virtual Private Wire Service (VPWS) path exists between the two routers. In such cases, the eBGP configuration can simply use the interface IP addresses on that particular link. For example, in Figure 13-16, a single serial link exists between Routers E1 and I3-1, and they can reasonably use the serial link’s IP addresses, as shown in Example 13-2.

However, when redundant Layer 3 paths exist between two eBGP neighbors, the use of interface IP addresses for the underlying TCP connection can result in an outage when only one of the two links fails. BGP neighborships ...

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