Routing Protocols Comparison

	RIP v1	RIP v2	EIGRP	OSPF	BGP
Interior/Exterior?	Interior	Interior	Interior	Interior	Exterior
Type	Distance Vector	Distance Vector	Hybrid distance vector	Link-state	Path Vector
Default Metric	Hop count	Hop count	Delay, bandwidth, reliability, and load, using the Diffusing Update Algorithm (DUAL)	Cost	Multiple Attributes
Administrative Distance	120	120	90 (internal) 170 (external)	110	20 (external) 200 (internal)
Hop count Limit	15	15	224 (100 default)	None	EBGP Neighbors: 1 (default) IBGP Neighbors: None
Convergence	Slow	Slow	Very Fast	Fast	Average
Update timers	30 seconds	30 seconds	Only when change occurs	Only when changes occur; (LSA table is refreshed every 30 minutes, however)	Only when changes occur
Updates	Full table	Full table	Only Changes	Only Changes	Only Changes
Classless	No	Yes	Yes	Yes	Yes
Supports VLSM	No	Yes	Yes	Yes	Yes
Algorithm	Bellman-Ford	Bellman-Ford	DUAL	Dijkstra	Best Path Algorithm
Update Address	Broadcast	224.0.0.9	224.0.0.10	224.0.0.5 (All SPF Routers) 224.0.0.6 (DR’s and BDR’s)	Unicast
Protocol and Port	UDP port 520		IP Protocol 88	IP Protocol 89	TCP port 179
Methodology	Selects routers with the lowest hop count	Selects routers with the lowest hop count	Sends hello packets every five seconds to neighbors (can interoperate with IGRP) to see if the neighbors are still available	Develops adjacencies with its neighbors, periodically sending hello packets to neighbors, flooding changes to neighbors when a link’s status changes, and sending “paranoia updates” to neighbors every 30 minutes of all recent link state changes	If the network, its complete AS path, and the gateway are correct,    Then the route is compared with other routes to the same network.  If    the new route is better than the current one, then it is flooded to    other BGP peers
Ideal topology	Smaller networks that aren’t very dynamic, have fewer than 15 hops, and are not subnetted from classful boundaries	maller networks that aren’t very dynamic, have fewer than 15 hops	Any network, small to very large; all routers must be Cisco	Any network, small to very large	Used by ISPs & Large Enterprises.
Standard	RFC 1058	RFC 1388	proprietary of Cisco	RFC 2328	RFC 1105
Strengths	- Easy to configure and use. - Since it has been around so long, it is well known and widely used.	- Easy to configure and use. - Since it has also been around so long, it is well known and widely used. - Version 2 adds support for VSLM or Classless Internet Domain Routing (CIDR), MD5 Authentication, and route summarization.	- Uses DUAL to provide very quick convergence and a loop-free network. - Supports IP and IPX. - Requires less CPU than OSPF (see next section). - Requires little bandwidth for routing updates. - Supports VLSM or CIDR. - Uses the delay, bandwidth, reliability, and load of a link as its metric; this makes it very accurate in selecting the proper route. - Offers backward compatibility with IGRP.	- Converges quickly, compared to a distance vector protocol. - Routing update packets are small, as the entire routing table is not sent. - Not prone to routing loops. - Scales very well to large networks. - Recognizes the bandwidth of a link, taking this into account in link selection. - Supports VLSM or CIDR. - Supports a long list of optional features that many of the other protocols do not.
Weaknesses	- Limited to a hop count of 15; after a packet travels through 15 routers and still has another router to travel to, it will be discarded. -Doesn’t support a variable-length subnet mask (VLSM), which means that it sends routing updates based only on a fixed-length subnet mask (FLSM) or routes that fall on classful boundaries. So RIP V1 will not work with a network that has been subnetted beyond the normal /8, /16, /24 (255.0.0.0, 255.255.0.0, 255.255.255.0) or Class A, B, and C network boundaries. -Converges slowly, especially on large networks. - Doesn’t have knowledge of the bandwidth of a link. - Doesn’t support multiple paths for the same route. - Routing updates can require significant bandwidth, as the entire routing table is sent when a link’s status changes. - Prone to routing loops.	- Limited to a hop count of 15; after a packet travels through 15 routers and still has another router to travel to, it will be discarded. - Converges slowly, especially on large networks. - Doesn’t have knowledge of the bandwidth of a link. - Doesn’t support multiple paths for the same route. - Routing updates can require significant bandwidth as the entire routing table is sent when a link’s status changes. - Prone to routing loops.	- Not an Internet standard; all routers must be from Cisco Systems.	More complex to configure and understand than a distance vector protocol