A. Every 90 seconds.
B. Every 30 seconds.
C. Every 60 seconds.
D. RIPv1 does not broadcast periodically.
Correct Answer: B
Distance-Vector Routing Protocols
The first IGP routing protocols introduced were distance-vector routing protocols. They used the Bellman-Ford algorithm to build the routing tables. With distance-
vector routing protocols, routes are advertised as vectors of distance and direction. The distance metric is usually router hop count. The direction is the next-hop
router (IP address) toward which to forward the packet. For RIP, the maximum number of hops is 15, which can be a serious limitation, especially in large
nonhierarchical internetworks. Distance-vector algorithms call for each router to send its entire routing table to only its immediate neighbors. The table is sent
periodically (30 seconds for RIP). In the period between advertisements, each router builds a new table to send to its neighbors at the end of the period. Because
each router relies on its neighbors for route information, it is commonly said that distance-vector protocols “route by rumor.” Having to wait half a minute for a new
routing table with new routes is too long for today’s networks. This is why distance-vector routing protocols have slow convergence. RIPv2 and RIPng can send
triggered updates—full routing table updates sent before the update timer has expired. A router can receive a routing table with 500 routes with only one route
change, which creates serious overhead on the network (another drawback). Furthermore, RFC 2091 updates RIP with triggered extensions to allow triggered
updates with only route changes. Cisco routers support this on fixed point-to-point interfaces.