- BGP联盟类似于反射器,但是引入了内层BGP,通过内层BGP间路由信息传递,从而避免水平分割原则(从ibgp学习到的路由信息不会发送给ibgp),但是联盟之间的环路会从bgp选路原则的10和11来体现,通过类似于as-path的原则进行防环。
- 原理需求相似反射器
- 类似于在外层bgp的基础上配置了内层bgp。利用外层给内层传递路由信息。
- 规划R3的区域为65000,R4和R5的区域为65001,外层AS都为300
R1配置
#
sysname R1
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interface GigabitEthernet0/0/0
ip address 13.1.1.1 255.255.255.0
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interface LoopBack0
ip address 11.11.11.11 255.255.255.255
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bgp 100
peer 13.1.1.3 as-number 300
network 11.11.11.11 255.255.255.255
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R2配置
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sysname R2
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interface GigabitEthernet0/0/0
ip address 25.1.1.2 255.255.255.0
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bgp 200
peer 25.1.1.5 as-number 300
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ipv4-family unicast
undo synchronization
peer 25.1.1.5 enable
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R3配置 与R4形成联盟反射器
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sysname R3
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interface GigabitEthernet0/0/0
ip address 13.1.1.3 255.255.255.0
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interface GigabitEthernet0/0/1
ip address 34.1.1.3 255.255.255.0
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interface LoopBack0
ip address 3.3.3.3 255.255.255.255
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bgp 65000
confederation id 300 //配置父AS号为300
confederation peer-as 65001 //配置内部联盟对端的AS号为65000,本地为65000
peer 4.4.4.4 as-number 65001 //与R4的loopback接口建立连接
peer 4.4.4.4 ebgp-max-hop 2 //由于与R4之间建立EBGP邻居,所以要设置跳数
peer 4.4.4.4 connect-interface LoopBack0
peer 13.1.1.1 as-number 100
peer 4.4.4.4 next-hop-local
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ospf 1 router-id 3.3.3.3
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 34.1.1.0 0.0.0.255
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R4
#
sysname R4
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interface GigabitEthernet0/0/0
ip address 45.1.1.4 255.255.255.0
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interface GigabitEthernet0/0/1
ip address 34.1.1.4 255.255.255.0
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interface LoopBack0
ip address 4.4.4.4 255.255.255.255
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bgp 65001
confederation id 300
confederation peer-as 65000
peer 3.3.3.3 as-number 65000
peer 3.3.3.3 ebgp-max-hop 2
peer 3.3.3.3 connect-interface LoopBack0
peer 5.5.5.5 as-number 65001 //与R5建立正常的IBGP邻居
peer 5.5.5.5 connect-interface LoopBack0
peer 3.3.3.3 next-hop-local
peer 5.5.5.5 next-hop-local
#
ospf 1 router-id 4.4.4.4
area 0.0.0.0
network 4.4.4.4 0.0.0.0
network 34.1.1.0 0.0.0.255
network 45.1.1.0 0.0.0.255
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R5配置
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sysname R5
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interface GigabitEthernet0/0/0
ip address 25.1.1.5 255.255.255.0
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interface GigabitEthernet0/0/1
ip address 45.1.1.5 255.255.255.0
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interface LoopBack0
ip address 5.5.5.5 255.255.255.255
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bgp 65001
confederation id 300
peer 4.4.4.4 as-number 65001
peer 4.4.4.4 connect-interface LoopBack0
peer 25.1.1.2 as-number 200
peer 4.4.4.4 next-hop-local
#
ospf 1 router-id 5.5.5.5
area 0.0.0.0
network 5.5.5.5 0.0.0.0
network 45.1.1.0 0.0.0.255
#