Start and run the RIP Routing Protocol

Many friends may not be familiar with the RIP routing protocol. This simple and dynamic routing protocol has been widely praised and has been applied in many practical enterprises and networks. Next we will introduce all aspects of it, including its working mechanism, startup, and running.

RIP route protocol

As a simple dynamic Routing Protocol, RIP is widely used in practical use) distance vector protocol for exchanging router information with the host. The latest version is RIP v2, this is also known as distance vector protocol. The router collects all the different paths that can reach the destination, and stores the path information about the minimum number of sites to reach each destination. Besides the Optimal Path to the destination, all other information is discarded. At the same time, the router also uses the RIP Protocol to notify neighboring routers of the route information collected. In this way, the correct route information gradually spreads to the entire network ｡

1. RIP Working Mechanism

RIP is a protocol based on the Distance-Vector algorithm. It uses UDP packets to exchange route information) to measure the distance to the sink, called Routing Metric. In RIP, the number of hops from a router to a directly connected network is 0, the number of hops that can be reached by a vro is 1, and the rest are pushed accordingly. to limit the convergence time, the RIP requires that the metric value be 0 ~ An integer between 15 and 16. The number of hops greater than or equal to 16 is defined as infinite, that is, the destination network or host is inaccessible ｡

RIP sends a route refresh packet every 30 seconds. If a route refresh packet sent from a network neighbor is not received within 180 seconds, all routes of the network neighbor are marked as inaccessible. If the route refresh packet sent from a network neighbor is not received within 300 seconds, then the route of the network neighbor is cleared from the corresponding protocol routing table ｡

To improve performance and prevent the generation of routing loops, the RIP routing protocol supports horizontal Split Horizon and Poison Reverse. RIP can also introduce routes obtained by other routing protocols ｡

Each router running RIP manages a routing database. The routing database contains all the route entries that can reach the destination in the network. These route entries contain the following information ｡

Destination Address: the address of the host or network ｡

Next Hop address: the address of the next router to be routed to the destination ｡

Interface: refers to the interface for forwarding packets ｡

Metric value: the overhead of the router to reach the destination. It is a value ranging from 0 ~ An integer between 16 ｡

Timer: the time from the last time the route entry was modified to the current time. The timer is reset to 0 each time the route entry is modified ｡

Route Tag: Indicates whether a route entry is an internal route entry or an external route entry ｡

2. Start and run the RIP Routing Protocol

The entire process of RIP startup and running can be described as follows:

When a router initiates RIP, it sends a request packet to the adjacent router in the form of broadcast or multicast. After the RIP of the adjacent router receives the request packet, it responds to the request, the response packet containing the local route table information ｡

After the router receives the response packet, it modifies the local route table and sends the trigger modification packet to the adjacent router to broadcast the route modification information, the router sends a message that triggers the modification to its adjacent routers. After a series of broadcasts that trigger the modification, Each router can obtain and maintain the latest route information ｡

At the same time, RIP broadcasts the local route table to the adjacent router every 30 seconds. After the neighboring router receives the packet, it maintains the local route, selects an optimal route, and broadcasts the modification information to the adjacent network, in this way, the updated route can be globally valid. At the same time, the RIP routing protocol uses the timeout mechanism to process the timeout of outdated routes to ensure the real-time and effective routing ｡