Routing Protocols

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  • Topic: Routing protocol, Routing Information Protocol, Routing protocols
  • Pages : 8 (2623 words )
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  • Published : January 30, 2012
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1.) Routing Information Protocol (Version 2)
Routing Information Protocol version 2 (RIPv2) is an extension of the Routing Information Protocol (RIP), designed to increase the quantity of useful information that can be stored in messages, while adding a measure of security. This classless distance-vector routing protocol, which also uses User Datagram Protocol (UDP) port 520, was first defined in Request For Comment (RFC) 1388 (in the year 1993) and was updated in RFC 1723 (in the year 1994) and RFC 2453 (in the year 1998). It is similar to its predecessor (RIPv1) in the following ways: updates are also sent every 30 seconds; the hop limit is also 15; triggered updates are also used, as well as UDP Port 520; split horizon with poisoned reverse is also used to prevent loops and counting to infinity; it has the same administrative distance, which is 120 on Cisco routes; it also summarizes IP networks at network boundaries; and automatic summarization can also be disabled using the no auto-summary command. However, RIPv2 is more enhanced, with Variable-Length Subnet Mask (VLSM) and Classless Inter-Domain Routing (CIDR) support, as well as support for route authentication. RIPv2 can be used in small networks where VSLM is required, or at the edge of the larger networks.

Furthermore, since RIPv2 multicasts route updates, it does send the subnet mask with route updates. While RIPv1 uses the IP address to broadcast its route updates to the other RIP routers, RIPv2 uses the IP address to multicast the router updates. With RIPv2, authentication can be enabled on any router interface to ensure that communication only takes place with RIP routers that are part of the network. If authentication is enabled, RIP routers will only accept and process the route updates holding the correct authentication password. Although RFC 1723 describes plain text passwords for RIPv2, Message Digest (MD) 5, as defined in RFC 1321, may also protect routers against intentional misdirection by malicious users. The new implementation also includes a built-in Internet Control Message Protocol (ICMP) Router Discovery (RFC 1256) mechanism. A maximum of 25 routes are contained in RIPv2 messages. When authentication is used, the figure is 24 routes.

* Cisco Certification Academy (2009). Routing Information Protocol version 2 (RIPv2). Retrieved October 31, 2011 from * DiNicolo, D. (2007). Routing Information Protocol Version 2 (RIPv2). Retrieved October 31, 2011 from * Javvin Company (2004). RIP2: Routing Information Protocol version 2. Retrieved October 31, 2011 from * Oracle Corporation (2010). Routing Information Protocol Version 2 (RIPv2). Retrieved October 31, 2011 from

2.) Interior Gateway Routing Protocol
The Interior Gateway Routing Protocol (IGRP) is a Cisco interior routing protocol. An interior routing protocol is designed to be used within an autonomous system (the private network of an organization), as opposed to an exterior routing protocol which operates between autonomous systems. IGRP is a distance-vector protocol. Although link-state protocols are superior because they send local information to all nodes in the internetwork, distance-vector protocols are appropriate for small internetworks, since they mathematically compare routes using some measurement of distance and require much less configuration and management. In the mid-1980’s, the most widespread interior routing protocol was the Routing Information Protocol (RIP). Although it was quite convenient for routing within small-sized to moderate-sized, relatively homogeneous internetworks, its limits were being pushed by network growth. As a result, Cisco developed...
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