Improving Lost Peer Detection Methods

BE.

To improve lost peer detection for the two diverse multihop External Border Gateway Protocol (EBGP) peerings, two methods can be used from the given options:

1. Use Bidirectional Forwarding Detection (BFD) for the peers: BFD is a protocol that provides low-overhead, subsecond failure detection of network paths between two routers, including those that traverse one or more intermediate hops. BFD can detect failures in the forwarding path and the control plane, which makes it an ideal candidate for detecting lost EBGP peers. By configuring BFD on the EBGP peers, any loss of connectivity between the peers can be detected quickly and accurately, allowing the routing protocol to converge and restore traffic flow in a timely manner.

2. Use subsecond keepalives for the peers: Keepalive messages are used by networking protocols to verify that the peer is still alive and reachable. By configuring subsecond keepalives for the EBGP peers, any loss of connectivity between the peers can be detected quickly. If the keepalive messages are not received within the specified time, the routing protocol can consider the peer to be lost and take appropriate action to restore traffic flow.

Option D, using subsecond hold timers for the peers, is not a good option for lost peer detection because hold timers are used to specify how long a router should wait before declaring a peer dead. This is a reactive measure, whereas the goal is to proactively detect lost peers.

Option B, using Selective Address Tracking and match the peers, is not directly related to lost peer detection. Selective Address Tracking (SAT) is a feature that tracks only a subset of IP addresses on an interface, which can reduce the overhead of tracking all the IP addresses. Matching peers is also not directly related to lost peer detection.

Option E, using Fast Peering Session Deactivation for the peers, is also not related to lost peer detection. Fast Peering Session Deactivation (FPD) is a feature that enables the fast teardown of peering sessions, which can be useful in situations where a peer is being removed or where there is a network outage.

Option F, using subsecond minimum route advertisement Interval timers for the peers, is not directly related to lost peer detection. This option refers to the frequency at which routing updates are sent between peers, which can impact convergence time but does not directly address lost peer detection.