Routing foundation - dynamic routing

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Preface

The front said , Routing has 3 Source of species ：

• Direct link routing
• Static routing
• Dynamic routing

Static routing is manually configured by the administrator , Unable to automatically respond to changes in network topology ; Dynamic routing enables routers to obtain routes from other routers using routing protocols , When the network topology changes , The router will automatically update the routing information .

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One 、 What is dynamic routing ？

Dynamic routing means that the router can automatically establish its own routing table , And it can be adjusted timely according to the changes of the actual situation .

Dynamic routing is a concept relative to static routing , It refers to the router can automatically establish its own routing table according to the specific routing information exchanged between routers , And it can adjust automatically according to the changes of links and nodes . When the nodes in the network or the links between nodes fail , Or when there are other available routes , Dynamic routing can choose the best available route and continue to forward messages .

From baidu baike

Two 、 Routing protocol

1. summary

• A language for exchanging information between routers
• Share routing information
• Maintain routing tables 、 Provide the best forwarding path
  Since the routing table can be dynamically established and maintained , There is no lack of programming . Protocol in Network Planning , So it is with . Pass code ,

2. Overview of routing protocols

3. classification

According to the scope of action

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IGP（Interior Gateway Protocol） Internal gateway protocol	Running on the AS Inside In exchange for AS Routing within
EGP（Exterior Gateway Protocol） External gateway protocol	Running on the AS outside In exchange for AS The route between
AS（Autonomous Systems） Autonomous systems	A network under a single management mechanism

According to the protocol algorithm

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DV（Distance-Vector） Distance vector	Based on distance vector algorithm , The router does not understand the network topology Similar road signs , What I hear Such as ：RIP、EIGRP
LS（Link-State）	be based on SPF（Shortest Path First, Shortest path first ） Algorithm , The router understands the complete network topology Like a map Such as ：OSPF、IS-IS

According to whether the sent update carries a mask ：

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Classful Some kind	No mask RIPv1、IGRP
Classless No class	Carry mask RIPv2、EIGRP、OSPF、IS-IS、BGP

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