Shulou(Shulou.com)06/02 Report--

Overview of dynamic routin

The difference between static routing and dynamic routing

Static routes are routing information that is manually configured by a network administrator. When the topology of the network or the state of the link changes, the network administrator needs to manually modify the relevant static route information in the routing table. Static routing information is private by default and is not passed on to other routers. Of course, the network administrator can also make the router shared by setting it up. Static routing is generally suitable for relatively simple network environment, in which it is easy for network administrators to clearly understand the topology of the network and to set up the correct routing information.

Dynamic routing means that routers can automatically establish their own routing table, routers can learn from each other, and can adjust timely according to the actual situation. The operation of the dynamic routing mechanism depends on two basic functions of the router: the maintenance of the routing table and the timely exchange of routing information between routers.

The process of dynamic routing Autonomous Learning

Characteristics of dynamic routin

1. Implementation based on some routing protocol

two。 Reduced administrative tasks

In the current network, it is impossible for the administrator to experiment with the interconnection of the whole network by setting the routing table manually, and the workload is too large. Dynamic routing can solve this problem (dynamic routing is basically used in the current network).

3. Take up the network bandwidth

Dynamic routing takes up part of the bandwidth in the process of learning.

Dynamic routing protocol

Overview: the language used to exchange information between routers

Metrics: hop count, bandwidth, load, delay, reliability, cost

Convergence: the process by which all routing tables reach a consistent state

Classification of dynamic routing protocols

1. Distance vector routing protocol

Choose a route based on the number of routers locked from the source network to the destination network

RIP

IGRP

two。 Link-state routing protocol

Choose a route by considering each path from the source network to the destination network

OSPF

IS-IS

RIP routing Information Protocol

The basic concept of RIP

RIP (routing information protocol) is a true distance vector routing protocol.

1. Update regularly

two。 Learn the routing table of a neighbor

3. Broadcast updates

4. Full routing table update

The formation process of routing table

Routers learn directly connected rout

The network segment to which the router itself is connected

When the update cycle reaches 30 seconds, the router sends a routing table to its neighbors

3. After 30 seconds, the second cycle follows the new cycle to send the routing table again.

Metrics and update time of RIP

RIP metric is hop count

The maximum number of hops is 15 hops, and 16 hops are unreachable.

RIP update time

Send routing update messages every 30 seconds, UDP520 port

RIP routing update messa

Send the entire routing table information

The formation of routing loops

1. Routing table information synchronization after autonomous learning of adjacent routing table

two。 When one of the network segments of a routing table is suddenly disconnected, the router's routing table marks the metric of that segment as 16.

3. Before the update cycle of R3 comes, R2 first sends an update to R3Magine R3 to learn the wrong routing entry, and he will think that the packet of this network segment should be handed over to R2 for processing.

4. In the next update, R2 will learn the error entry based on the error entry on R3 and send the packet of that network segment to R3 for processing, thus forming a routing loop.

How to prevent routing loops from happening?

Split horizon can prevent the occurrence of routing loops

Learn routing information from an interface and no longer send it out that interface

At the same time, it can also reduce the link bandwidth resources occupied by routing update information.

Classification of RIP protocols

1,RIP V1

2.RIP V2

3. The difference between the two

Configuration and Verification of dynamic routing in RIP Protocol

Lab environment: GNS3,3 routes, 2 VPS clients

Route R1 port f0amp 0: 192.168.10.1ax 24

Port f0swap 1purl 192.168.20.1Univer 30

Route R2 port f0amp 0: 192.168.20.2ax 30

Port f0swap 1purl 192.168.30.1Univer 30

Route R3 port f0swap 0: 192.168.30.2max 30

Port f0swap 1purl 192.168.40.1Univer 24

PC1 IP: 192.168.10.10

PC2 IP:192.168.40.10

1. Open GNS3 and match it according to the following topological diagram

two。 Enter R1 and configure the interface with ip and subnet mask

3. Enter R2 and configure the interface with ip and subnet mask

4. Enter R3 and configure the interface with ip and subnet mask

5. Enter R1Magic R2GR3, enable RIP version 2, turn off automatic summarization of RIP V2 routes, and add network segment records.

6. Assign addresses to PC1 and PC2, respectively

7. PC1pingPC2 for verification

8. Successful Unicom, successful dynamic routing configuration of RIP protocol

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