Basic Features of RIP

Next we will parse the content of the route information protocol RIP. For some of the content of this protocol, we will mainly explain the background of this Protocol, as well as the contents related to the route update metric, stability, and timer. I hope this will help you.

I. background

The route information protocol (RIP) uses the number of hops as the distance vector protocol of metric. RIP is widely used in global Internet routing. It is an internal gateway protocol that implements routing functions within the autonomous system. external gateway protocol (such as edge gateway protocol BGP) is used for routing between different Autonomous Systems. the predecessor of RIP is the Xerox protocol GWINFO. Later versions of routed were pronounced as/rutdi/) encapsulated in the Berkeley standard release Unix (BSD) in 1982 ). RIP itself is developed into the protocol of the special network, and some protocol families use the RIP variant, such as: AppleTalk route table maintenance protocol RTMP) and Banyan VINES route table protocol RIP) is based on the IP version of RIP. the latest enhanced version of RIP is the RIP2 specification, which allows more information to be contained in the RIP group and provides a simple authentication mechanism.

Ip rip is formally defined in two documents: RFC 1058 and 1723.RFC 1058 (1988) Describe the first implementation of RIP, and RFC 1723 (1994) is its update, the RIP group is allowed to carry more information and security features.

This article briefly introduces the basic capabilities and features of RIP, including the route update process, RIP route metric, route stability and timer.

Ii. route update

RIP sends route update information at the specified interval and when the network topology changes. when a vro receives an Update route entry that contains a table entry, it updates its route table. The value of metric for this path is added with 1, and the sender is recorded as the next hop. the RIP Router only maintains the path with the minimum metric value in the destination Optimal Path ). after updating the route table, the router immediately sends a route update notification to other routers, which is irrelevant to the periodically sent update information.

Iii. RIP route metric

The routing information protocol RIP uses a single route metric hop count) to measure the distance from the source network to the target network. each hop in the path from the source to the destination is assigned a hop value, which is usually 1. when the router receives the route update information that contains the new or changed destination network table items, it adds the metric value to 1 and saves it to the route table. the IP address of the sender is the next hop address.

RIP restricts the maximum number of hops from the source to the target to prevent routing loops. The maximum value is 15. if the router receives the route update information containing the new or changed table items and adds the metric value to 1 to become an infinite number (16), the destination network cannot be reached.

Iv. RIP Stability

To adapt to fast network topology changes, RIP defines some stable features that are the same as those of other routing protocols. for example, the routing information protocol RIP implements the split-horizon and hold-down mechanisms to prevent route information from being transmitted incorrectly. in addition, the limit on the number of hops of RIP also prevents the infinite growth of the route ring.

5. RIP Timer

The routing information protocol RIP uses some timers to control its performance, including the route update timer, route timeout, and route clearing timer. the interval at which route update timers record periodic updates, usually 30 seconds. A small random number of seconds is added each time the timer is reset to prevent conflict. each route table entry has a related route time-out timer. When the route time-out timer expires, the path is marked as invalid, but it is still saved in the routing table, it is not cleared until the route clearing timer expires.