BGP分解实验·19——BGP选路原则之起源

news2025/2/24 5:44:04

当用不同的方式为BGP注入路由时，起源代码将标识路由的来源。

（在BGP表中，Network为“i”，重分布是“？”）

实验拓扑如下：

R2上将来自IGP的路由10.3.3.3/32用network指令注入BGP;在R4上将来自IGP的路由10.3.3.3/32使用重分布的方式引入BGP。

完成实验拓扑的基础配置R1如下：

hostname R1
!
interface Loopback0
 ip address 10.1.0.1 255.255.255.0
!
interface Loopback1
 ip address 10.1.1.1 255.255.255.0
!
interface Ethernet0/0
 ip address 10.12.1.1 255.255.255.0
 no sh
!
router bgp 100
 bgp router-id 1.1.1.1
 network 10.1.0.0 mask 255.255.255.0
 network 10.1.1.0 mask 255.255.255.0
 aggregate-address 10.1.0.0 255.255.0.0 summary-only
 neighbor 10.12.1.2 remote-as 234
!
end

R2的配置如下：

hostname R2
!
interface Loopback1
 ip address 2.2.2.2 255.255.255.255
!
interface Ethernet0/0
 ip address 10.12.1.2 255.255.255.0
 no sh
!
interface Ethernet0/1
 ip address 10.23.0.2 255.255.255.0
 no sh
!
router eigrp 10
 network 0.0.0.0
 passive-interface default
 no passive-interface Ethernet0/1
!
router bgp 234
 bgp router-id 2.2.2.2
 network 10.3.3.3 mask 255.255.255.255
 neighbor IBGP peer-group
 neighbor IBGP remote-as 234
 neighbor IBGP update-source Loopback1
 neighbor IBGP next-hop-self
 neighbor 3.3.3.3 peer-group IBGP
 neighbor 4.4.4.4 peer-group IBGP
 neighbor 10.12.1.1 remote-as 100
!
end

R3的配置如下：

hostname R3
!
interface Loopback0
 ip address 10.3.3.3 255.255.255.255
!
interface Loopback1
 ip address 3.3.3.3 255.255.255.255
!
interface Ethernet0/0
 ip address 10.23.0.3 255.255.255.0
 no sh
!
interface Ethernet0/1
 ip address 10.34.0.3 255.255.255.0
 no sh
!
router eigrp 10
 network 0.0.0.0
!
router bgp 234
 bgp router-id 3.3.3.3
 neighbor IBGP peer-group
 neighbor IBGP remote-as 234
 neighbor IBGP update-source Loopback1
 neighbor 2.2.2.2 peer-group IBGP
 neighbor 4.4.4.4 peer-group IBGP
!
end

R4的配置如下：

hostname R4
!
interface Loopback1
 ip address 4.4.4.4 255.255.255.255
!
interface Ethernet0/0
 ip address 10.45.2.4 255.255.255.0
 no sh
!
interface Ethernet0/1
 ip address 10.34.0.4 255.255.255.0
 no sh
!
router eigrp 10
 network 0.0.0.0
 passive-interface Ethernet0/0
!
router bgp 234
 bgp router-id 4.4.4.4
 redistribute eigrp 10 route-map RED
 neighbor IBGP peer-group
 neighbor IBGP remote-as 234
 neighbor IBGP update-source Loopback1
 neighbor IBGP next-hop-self
 neighbor 2.2.2.2 peer-group IBGP
 neighbor 3.3.3.3 peer-group IBGP
 neighbor 10.45.2.5 remote-as 500
!
ip prefix-list RED seq 5 permit 10.3.3.3/32
!
route-map RED permit 10
 match ip address prefix-list RED
!

R5的配置如下：

hostname R5
!
interface Loopback2
 ip address 10.1.2.5 255.255.255.0
!
interface Loopback3
 ip address 10.1.3.5 255.255.255.0
!
interface Ethernet0/0
 ip address 10.45.2.5 255.255.255.0
 no sh
!
router bgp 500
 bgp router-id 5.5.5.5
 network 10.1.2.0 mask 255.255.255.0
 network 10.1.3.0 mask 255.255.255.0
 aggregate-address 10.1.0.0 255.255.0.0 summary-only
 neighbor 10.45.2.4 remote-as 234
!
end

在R3上查看网络10.3.3.3/32的BGP表和路由详细信息如下：