Routing Protocols Flashcards

When redistributing external routes into EIGRP, which metric components must be specified?

Answer: Bandwidth, delay, reliability, load, and MTU

Redistributing into EIGRP requires all five metric components (bandwidth, delay, reliability, load, MTU) to be defined via `default-metric` or inline, since EIGRP has no default for external sources.

Which command displays OSPF neighbor adjacency states and identifies the DR/BDR on each segment?

Answer: show ip ospf neighbor

`show ip ospf neighbor` lists all OSPF neighbors, their adjacency states (Full, 2WAY, etc.), dead timers, and their DR/BDR roles on each network segment.

Which OSPF router type and command is used to perform inter-area route summarization?

Answer: ABR using `area range`

Inter-area summarization in OSPF is configured on ABRs with the `area range` command, which aggregates Type 3 Summary LSAs sent between areas.

Which BGP attribute is advertised to eBGP neighbors to influence which entry point into your AS neighboring ASes should use?

Answer: MED (Multi-Exit Discriminator)

MED is sent to external BGP neighbors to suggest a preferred entry point into your AS; lower MED values are preferred and it is the primary tool for influencing inbound traffic from adjacent ASes.

In EIGRP, what occurs when a router loses its Successor and no Feasible Successor exists in the topology table?

Answer: It enters Active state and sends QUERY messages to all neighbors

When no Feasible Successor exists, EIGRP transitions the route to Active state and sends QUERY messages to all neighbors seeking an alternative path to the destination.

What does setting `ip ospf priority 0` on an interface accomplish?

Answer: Makes the router ineligible to become DR or BDR

Setting OSPF priority to 0 makes the router ineligible for DR/BDR election on that segment; only routers with priority ≥ 1 can be elected as DR or BDR.

Which EIGRP feature is commonly deployed on spoke routers in a hub-and-spoke WAN topology to limit query scope and prevent spoke-to-spoke transit routing?

Answer: EIGRP stub routing

EIGRP stub routing designates a router as a stub, preventing it from being used as a transit path and causing hub routers to not send QUERY messages to stub spokes, reducing convergence time.