Which two statements about the function of the stub feature in EIGRP are true? (Choose two.)
A. It stops the stub router from sending queries to peers.
B. It stops the hub router from sending queries to the stub router.
C. It stops the stub router from propagating dynamically learned EIGRP prefixes to the hub routers .
D. It stops the hub router from propagating dynamically learned EIGRP prefixes to the stub routers .
The answers sited as correct, B&C are the correct answers. A stub router signals to the hub or adjacent routers, that THOSE routers should not send queries to the stub. A stub router can still query adjacent routers for routes if they are removed from the stub’s routing table. So A is not correct. And Stubs still learn dynamic routes from adjacent routers, so D is not correct either.
Scooby, as per you text, it should be B. The hub isn’t querying the stub.
C is still valid, since the stub feature is blocking the stub router to send dynamic updates (unless specified otherwise)
R1(config-router)#eigrp stub ?
connected Do advertise connected routes
leak-map Allow dynamic prefixes based on the leak-map
receive-only Set receive only neighbor
redistributed Do advertise redistributed routes
static Do advertise static routes
summary Do advertise summary routes
The hub router will still send the complete eigrp table/topology, unless configured otherwise. (using summary e.g.)
I’m thinking the answers should be A, D
The Enhanced Interior Gateway Routing Protocol (EIGRP) Stub Routing feature improves network stability, reduces resource utilization, and simplifies stub router configuration.
Stub routing is commonly used in a hub and spoke network topology. In a hub and spoke network, one or more end (stub) networks are connected to a remote router (the spoke) that is connected to one or more distribution routers (the hub). The remote router is adjacent only to one or more distribution routers. The only route for IP traffic to follow into the remote router is through a distribution router. This type of configuration is commonly used in WAN topologies where the distribution router is directly connected to a WAN. The distribution router can be connected to many more remote routers. Often, the distribution router will be connected to 100 or more remote routers. In a hub and spoke topology, the remote router must forward all nonlocal traffic to a distribution router, so it becomes unnecessary for the remote router to hold a complete routing table. Generally, the distribution router need not send anything more than a default route to the remote router.
When using the EIGRP Stub Routing feature, you need to configure the distribution and remote routers to use EIGRP, and to configure only the remote router as a stub. Only specified routes are propagated from the remote (stub) router. The router responds to queries for summaries, connected routes, redistributed static routes, external routes, and internal routes with the message “inaccessible.” A router that is configured as a stub will send a special peer information packet to all neighboring routers to report its status as a stub router.
Any neighbor that receives a packet informing it of the stub status will not query the stub router for any routes, and a router that has a stub peer will not query that peer. The stub router will depend on the distribution router to send the proper updates to all peers.