Compare Routing Protocol Types
Distance Vector
Bellman-Ford or DUAL algorithm
Requires router to inform neighbors of topology changes periodically
RIPv1, RIPv2, IGRP
Does not have full knowledge of how to get to a destination
- Direction in which router or exit interface a packet should be forwarded
- Distance from its destination
Count to Infinity
- Routing loops
- RIP avoids with the following
- Split Horizon: Prohibit router from advertising a route back onto the interface from which it was learned
- Poison Reverse: Indicate to other routers that a route is no longer reachable and should not be considered from their routing tables
- Max number of hops – 15
EIGRP falls under this type as it uses routing by rumor as well. The router only knows of routes learned by it’s neighbor, it does not build a full database like OSPF does.
Link State
OSPF and ISIS
- Dijkstra’s algorithm – shortest path first (SPF)
Creates a full topology of the network and places themselves at the root of the tree
Path Vector
BGP: Maintains a list of AS’s that are traversed to reach a destination
