Interfering with BGP routing---community attributes

目录

The construction of experimental topology andIP地址的规划

IGP与BGP的配置 

BGP的宣告

干涉选路 

link mutation --- R1-R9之间链路断开

实验要求：

1.合理IP地址 
2.AS 1 2 3 内部使用OSPF 协议 , AS 1 AS 2Fully interconnected internallyIBGP邻居 ,ASAll in betweenEBGP邻居
3.PC 1 3 5 Routes belonging to telecommunications,Telecommunications must be used when communicatingAS 1 ;PC 2 4 6 A route belonging to China Unicom,Communication must use Unicom AS 2
4.若 R1-R9之间链路断开,The routing of telecommunications is still through telecommunications AS 1 通信

The construction of experimental topology andIP地址的规划

地址规划：R1与R5between network segments10.1.15.0/24,The rest of the network segments are analogous.The loopback segment uses the router sequence number,R1就为1.1.1.1/24.The user network segments are as follows192.168.1.0—192.168.6.0

IGP与BGP的配置 

IGP均使用OSPF协议,协议启动、After the announcement, check whether the routing table is complete

BGP中IBGPNeighbors use loopback interfaces to establish neighbors,EBGPNeighbors use direct connection to build neighbors

BGP的宣告

R9

R10

 R11

干涉选路 

1、Mark the traffic that needs to be interfered with as a community attribute（Distinguish the traffic of China Telecom and China Unicom）

The traffic is first crawled through the prefix list

 Then use the routing policy to modify the attribute

 BGPNeighbor call

peer 10.1.19.1 route-policy com export

在R9与R10上抓取1.0、2.0、3.0、4.0网段,R11上抓取5.0、6.0网段 

2、Distinguish the traffic of China Telecom and China Unicom through different markers and interfere with routing

题目要求：Telecom routing,Telecommunications must be used when communicatingAS 1 ;Unicom routing,Communication must use Unicom AS 2

through topology analysis,R11在学习AS3中的路由时,由于R5的router-id小,所以会通过R5去学习,不符合题目要求.可在R11Modify the local priority on the solution

Captured by community attributes

The routing policy modifies the local priority

Neighbor call（R5-com1 R8com2）

peer 10.1.51.5 route-policy com1 import
peer 10.1.81.8 route-policy com2 import

此时可以查看BGP表

It can be seen that the route selection meets the requirements 

The same is true after completionR9与R10Learn from intervention5.0、6.0的路由,Make the right choice,完成后查看路由表

link mutation --- R1-R9之间链路断开

R1与R9after disconnection,Need to let telecommunications still go through telecommunicationsAS通信,由于AS2的as-path优于AS1的,So it won't go to telecommunicationsAS,此时我们可以将AS2的as-path改大,so that it goes through telecommunicationsAS通信

Capture telecom traffic through community attributes

通过路由策略修改as-path

对R4的每个IBGPNeighbors make calls

Created heregroupgroup to perform bulk operations,to reduce the amount of configuration

Just solved itAS4telecommunication learningAS3的路由,It still needs to be resolved at this timeAS3学习AS4的路由,本次修改AS1的preferred-value（Huawei-specific attributes）make it betterAS2

Also grab it first

修改preferred-value

R4只需对EBGP邻居R3调用

At this point, the routing interference between going and returning has been completed,You can check the routing table to confirm

再通过PC测试

It can be seen that both going and returning meet the requirements,至此实验结束