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Today, I will talk to you about what distance vector routing protocols there are, which may not be well understood by many people. in order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

Distance vector routing protocol (English: distance-vector routing protocol) is one of the two major categories of routing protocols. These protocols use distance vector (distance-vector, abbreviated to DV) algorithm to determine the path of message exchange. Including Behrman-Ford algorithm, Ford-Fulkerson algorithm and DUAL FSM algorithm, are classified as distance vector algorithms.

Distance vector routing protocols include RIP, IGRP, and EIGRP.

RIP

RIP (routing Information Protocol) is a routing protocol based on distance vector algorithm, which uses hop count as a metric. It was originally defined in RFC 1058.

The main characteristics are as follows:

. use the hop count as a metric for selecting a path.

. if the hop count of a network exceeds 15J RIP, the route to the network cannot be provided.

. by default, routing updates are sent every 30 seconds via broadcast or multicast.

IGRP

IGRP (Interior Gateway routing Protocol) is a proprietary protocol developed by Cisco. The main design features of IGRP are as follows:

. use composite metrics based on bandwidth, delay, load, and reliability.

. by default, routing updates are broadcast every 90 seconds.

IGRP is the predecessor of EIGRP and is no longer in use.

EIGRP

EIGRP (enhanced IGRP) is a special distance vector routing protocol for Cisco. EIGRP has the following main characteristics:

. be able to perform unequal cost load balancing.

. use the diffusion update algorithm (DUAL) to calculate the shortest path.

. there is no need for regular updates like RIP and IGRP. Routing updates are sent only when the topology changes

Extended data:

The meaning of distance vector

As the name implies, distance vectors mean that routes are advertised with distance and direction vectors. The distance is determined by a metric such as hop count, and the direction is the next-hop router or exit interface.

Routers that use distance vector routing protocols do not know the entire path to the destination network. The router only knows:

In which direction or interface should the packet be forwarded

The distance between itself and the destination network

How distance vector routing protocols work

Some distance vector routing protocols require routers to periodically broadcast the entire routing table to each neighbor. This approach is inefficient because these routing updates not only consume bandwidth, but also consume the router's CPU resources when processed.

Distance vector routing protocols have some common characteristics.

Send periodic updates at regular intervals (30 seconds for RIP and 90 seconds for IGRP). Even if the topology does not change for several days, regular updates are constantly sent to all neighbors.

Neighbors are other routers that use the same link and are configured with the same routing protocol. A router knows only the network address of its interface and the remote network address that can be reached through its neighbors, but knows nothing about the rest of the network topology. Routers that use distance vector routing do not understand the network topology.

Broadcast updates are sent to 255.255.255.255. Neighboring routers configured with the same routing protocol will handle such updates. All other devices also process such updates at layers 1, 2, and 3, and then discard them. Some distance vector routing protocols use multicast addresses instead of broadcast addresses.

Periodically send entire routing table updates to all neighbors (but there are some exceptions, which we will discuss later). The neighbors who receive these updates must process the entire update, find useful information from it, and discard the rest of the useless information. Some distance vector routing protocols, such as EIGRP, do not send periodic routing table updates.

The function of the algorithm

The core of distance vector protocol is algorithm. The algorithm is used to calculate the best path and send this information to the neighbors.

An algorithm is a step used to complete a specific task, starting with a given initial state and ending at a defined end state. Different routing protocols use different algorithms to add routes to the routing table, send updates to neighbors, and determine paths.

The algorithm used for routing protocols defines the following procedures:

The mechanism for sending and receiving routing information.

A mechanism for calculating the best path and adding routes to the routing table.

A mechanism that detects and responds to topology changes.

After reading the above, do you have any further understanding of the distance vector routing protocols? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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