Which statement accurately describes iBGP and eBGP?

• A. iBGP runs within the same AS; eBGP runs between different ASes
• B. iBGP runs between routers in different AS; eBGP runs within the same AS
• C. Both run within the same AS
• D. iBGP and eBGP both require a direct connection

Answer: (A)

The distinction between iBGP and eBGP is based on the AS context of the peers. iBGP runs between routers that share the same autonomous system, so it’s used to distribute routing information inside a single organization’s network. eBGP, on the other hand, runs between routers in different autonomous systems, allowing neighboring networks to exchange routes at the border between distinct organizations. This is exactly what the statement conveys: iBGP within the same AS and eBGP between different ASes.

The other possibilities mix up where the sessions occur or add unnecessary constraints. For instance, iBGP can be multihop and doesn’t require a single direct hop, while eBGP often uses a direct connection but can be configured for multihop in certain setups.