预配置int lo0ip add 1.1.1.1 255.255.255.255int s2/1ip add 12.0.0.1 255.255.255.0no shrouter os 11net 0.
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预配置
int lo0
ip add 1.1.1.1 255.255.255.255
int s2/1
ip add 12.0.0.1 255.255.255.0
no sh
router os 11
net 0.0.0.0 0.0.0.0 a 0
int s2/1
ip add 12.0.0.2 255.255.255.0
no sh
int s2/2
ip add 23.0.0.2 255.255.255.0
no sh
router os 11
net 0.0.0.0 0.0.0.0 a 0
int s2/1
ip add 23.0.0.3 255.255.255.0
no sh
router os 11
net 0.0.0.0 0.0.0.0 a 0
实验过程：R1和R3建立EBGP邻居
第一步：配置R1和R3
R1(config)#router bgp 1
R1(config-router)#nei 23.0.0.3 remot 3
R1(config-router)#nei 23.0.0.3 ebgp-multihop 2
R1(config-router)#end
R3(config)#router bgp 2
R3(config-router)#nei 12.0.0.1 remote-as 1
R3(config-router)#nei 12.0.0.1 ebgp-multihop 2
R3(config-router)#end
第二步：查看R3的路由表
R3#sh ip rou
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/129] via 23.0.0.2, 00:00:03, Serial2/1
//这里为ospf的管理距离为110，过会儿看看后面（第五步的这里）
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/65] via 23.0.0.2, 00:31:44, Serial2/1
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
23.0.0.0/24 is subnetted, 1 subnets
C 23.0.0.0 is directly connected, Serial2/1
12.0.0.0/24 is subnetted, 1 subnets
O 12.0.0.0 [110/128] via 23.0.0.2, 00:31:44, Serial2/1
第三步：引入：IGP路由
R1(config)#router bgp 1
R1(config-router)#network 1.1.1.1 mask 255.255.255.255
第四步：查看BGP表
R1#sh ip b
BGP table version is 2, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
> 1.1.1.1/32 0.0.0.0 0 32768 i
第五步：查看路由表
R3#sh ip rou
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
B 1.1.1.1 [20/0] via 12.0.0.1, 00:01:31
//这里是EBGP 管理距离为20.
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/65] via 23.0.0.2, 00:26:54, Serial2/1
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
23.0.0.0/24 is subnetted, 1 subnets
C 23.0.0.0 is directly connected, Serial2/1
12.0.0.0/24 is subnetted, 1 subnets
O 12.0.0.0 [110/128] via 23.0.0.2, 00:26:54, Serial2/1
