EIGRP非等价负载均衡

Loopback0 2.2.2.2/24S1/3 12.12.12.2/30S1/2 12.12.12.5/30S1/3 12.12.12.6/30S1/2 12.12.12.1/30R2Loopback0 1.1.1.1/24R1E0/0 12.12.12.9/30Loopback0 3.3.3.3/24R3E0/1 12.12.12.14/30E0/0 12.12.12.10/30E0/1 12.12.12.13/30R4Loopback0 4.4.4.4/24 如图：

R1通过R2到R3走的是Serial线路。R1通过R4到R3走的是Ethernet线路。因此是非等价的。

通常在这种情况下，路由表中只有R1->R4->R3一条路由。

现在我们通过非等价负载均衡的办法，将两条路由都放进路由表中。

环境配置

R1

Router>enable

Router#configure terminal Router(config)#hostname r1 r1(config)#line console 0

r1(config-line)#logging synchronous r1(config-line)#exec-timeout 0 r1(config-line)#exit

r1(config)#interface loopback 0

r1(config-if)#ip address 1.1.1.1 255.255.255.0 r1(config-if)#exit

r1(config)#interface serial 1/2

r1(config-if)#ip address 12.12.12.1 255.255.255.252 r1(config-if)#no shutdown r1(config-if)#exit

r1(config)#interface ethernet 0/0

r1(config-if)#ip address 12.12.12.9 255.255.255.252 r1(config-if)#no shutdown r1(config-if)#exit

r1(config)#router eigrp 1

r1(config-router)#network 1.1.1.1 0.0.0.255 r1(config-router)#network 12.12.12.1 0.0.0.3 r1(config-router)#network 12.12.12.9 0.0.0.3 r1(config-router)#no auto-summary r1(config-router)#exit r1(config)#exit

R2

Router>enable

Router#configure terminal Router(config)#hostname r2 r2(config)#line console 0

r2(config-line)#logging synchronous r2(config-line)#exec-timeout 0 r2(config-line)#exit

r2(config)#interface loopback 0

r2(config-if)#ip address 2.2.2.2 255.255.255.0 r2(config-if)#exit

r2(config)#interface serial 1/3

r2(config-if)#ip address 12.12.12.2 255.255.255.252 r2(config-if)#no shutdown r2(config-if)#exit

r2(config)#interface serial 1/2

r2(config-if)#ip address 12.12.12.5 255.255.255.252 r2(config-if)#no shutdown r2(config-if)#exit

r2(config)#router eigrp 1

r2(config-router)#network 2.2.2.2 0.0.0.255 r2(config-router)#network 12.12.12.2 0.0.0.3 r2(config-router)#network 12.12.12.5 0.0.0.3 r2(config-router)#no auto-summary r2(config-router)#exit r2(config)#exit

R3

Router>enable

Router#configure terminal Router(config)#hostname r3 r3(config)#line console 0

r3(config-line)#logging synchronous r3(config-line)#exec-timeout 0 r3(config-line)#exit

r3(config)#interface loopback 0

r3(config-if)#ip address 3.3.3.3 255.255.255.0 r3(config-if)#exit

r3(config)#interface serial 1/3

r3(config-if)#ip address 12.12.12.6 255.255.255.252 r3(config-if)#no shutdown r3(config-if)#exit

r3(config)#interface ethernet 0/1

r3(config-if)#ip address 12.12.12.4 255.255.255.252 r3(config-if)#no shutdown r3(config-if)#exit

r3(config)#router eigrp 1

r3(config-router)#network 3.3.3.3 0.0.0.255 r3(config-router)#network 12.12.12.6 0.0.0.3 r3(config-router)#network 12.12.12.14 0.0.0.3 r3(config-router)#no auto-summary r3(config-router)#exit r3(config)#exit

R4

Router>enable

Router#configure terminal Router(config)#hostname r4 R4(config)#line console 0

R4(config-line)#logging synchronous r4(config-line)#exec-timeout 0 r4(config-line)#exit

r4(config)#interface loopback 0

r4(config-if)#ip address 4.4.4.4 255.255.255.0 r4(config-if)#exit

r4(config)#interfaceethernet0/0

r4(config-if)#ip address 12.12.12.10 255.255.255.252 r4(config-if)#no shutdown r4(config-if)#exit

r4(config)#interfaceethernet0/1

r4(config-if)#ip address 12.12.12.13 255.255.255.252

r4(config-if)#no shutdown r4(config-if)#exit

r4(config)#router eigrp 1

r4(config-router)#network 4.4.4.4 0.0.0.255 r4(config-router)#network 12.12.12.10 0.0.0.3 r4(config-router)#network 12.12.12.13 0.0.0.3 r4(config-router)#no auto-summary r4(config-router)#exit r4(config)#exit

显示路由表

R1

r1#show ip route

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

1.0.0.0/24 is subnetted, 1 subnets

C 1.1.1.0 is directly connected, Loopback0 2.0.0.0/24 is subnetted, 1 subnets

D 2.2.2.0 [90/2297856] via 12.12.12.2, 00:03:09, Serial1/2 3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/435200] via 12.12.12.10, 00:02:23, Ethernet0/0 4.0.0.0/24 is subnetted, 1 subnets

D 4.4.4.0 [90/409600] via 12.12.12.10, 00:02:23, Ethernet0/0 12.0.0.0/30 is subnetted, 4 subnets

D 12.12.12.12 [90/307200] via 12.12.12.10, 00:02:24, Ethernet0/0 C 12.12.12.8 is directly connected, Ethernet0/0

D 12.12.12.4 [90/2221056] via 12.12.12.10, 00:02:23, Ethernet0/0 C 12.12.12.0 is directly connected, Serial1/2 r1#show ipeigrp topology

IP-EIGRP Topology Table for AS(1)/ID(1.1.1.1)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,

r - reply Status, s - sia Status

P 12.12.12.12/30, 1 successors, FD is 307200 via 12.12.12.10 (307200/281600), Ethernet0/0 P 1.1.1.0/24, 1 successors, FD is 128256 via Connected, Loopback0

P 2.2.2.0/24, 1 successors, FD is 2297856 via 12.12.12.2 (2297856/128256), Serial1/2 P 3.3.3.0/24, 1 successors, FD is 435200

via 12.12.12.10 (435200/409600), Ethernet0/0 P 4.4.4.0/24, 1 successors, FD is 409600

via 12.12.12.10 (409600/128256), Ethernet0/0 P 12.12.12.8/30, 1 successors, FD is 281600 via Connected, Ethernet0/0

P 12.12.12.4/30, 1 successors, FD is 2221056 via 12.12.12.10 (2221056/21956), Ethernet0/0 via 12.12.12.2 (2681856/2169856), Serial1/2 P 12.12.12.0/30, 1 successors, FD is 2169856 via Connected, Serial1/2

R2

r2#show ip route

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

1.0.0.0/24 is subnetted, 1 subnets

D 1.1.1.0 [90/2297856] via 12.12.12.1, 00:17:48, Serial1/3 2.0.0.0/24 is subnetted, 1 subnets

C 2.2.2.0 is directly connected, Loopback0 3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/2297856] via 12.12.12.6, 00:17:48, Serial1/2 4.0.0.0/24 is subnetted, 1 subnets

D 4.4.4.0 [90/2323456] via 12.12.12.6, 00:17:48, Serial1/2 [90/2323456] via 12.12.12.1, 00:17:48, Serial1/3 12.0.0.0/30 is subnetted, 4 subnets

D 12.12.12.12 [90/21956] via 12.12.12.6, 00:17:49, Serial1/2 D 12.12.12.8 [90/21956] via 12.12.12.1, 00:17:48, Serial1/3 C 12.12.12.4 is directly connected, Serial1/2

r2#show ipeigrp topology

IP-EIGRP Topology Table for AS(1)/ID(2.2.2.2)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status

P 12.12.12.12/30, 1 successors, FD is 21956 via 12.12.12.6 (21956/281600), Serial1/2 via 12.12.12.1 (2221056/307200), Serial1/3 P 1.1.1.0/24, 1 successors, FD is 2297856 via 12.12.12.1 (2297856/128256), Serial1/3 via 12.12.12.6 (2349056/435200), Serial1/2 P 2.2.2.0/24, 1 successors, FD is 128256 via Connected, Loopback0

P 3.3.3.0/24, 1 successors, FD is 2297856 via 12.12.12.6 (2297856/128256), Serial1/2 via 12.12.12.1 (2349056/435200), Serial1/3 P 4.4.4.0/24, 2 successors, FD is 2323456 via 12.12.12.1 (2323456/409600), Serial1/3 via 12.12.12.6 (2323456/409600), Serial1/2 P 12.12.12.8/30, 1 successors, FD is 21956 via 12.12.12.1 (21956/281600), Serial1/3 via 12.12.12.6 (2221056/307200), Serial1/2 P 12.12.12.4/30, 1 successors, FD is 2169856

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status

via Connected, Serial1/2

P 12.12.12.0/30, 1 successors, FD is 2169856 via Connected, Serial1/3

从路由表里只能看到一条到R3的回环地址3.3.3.3（以下简称3.3.3.3）的路由 3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/435200] via 12.12.12.10, 00:02:23, Ethernet0/0 这是从R1的Ethernet0/0接口出去经过R4到R3的3.3.3.3。 而且Topology表里面也只有一条通往R3的3.3.3.3的路径 P 3.3.3.0/24, 1 successors, FD is 435200

via 12.12.12.10 (435200/409600), Ethernet0/0

也是经过R1的Ethernet0/0接口出去经过R4到R3的3.3.3.3，出去的。 从图上可以看到，我们其实有两条路径可以选择：

R1->R2->R3->3.3.3.3 R1->R4->R3->3.3.3.3

检查R2的Topology表后，发现R2到R3的3.3.3.3路由条目 P 3.3.3.0/24, 1 successors, FD is 2297856 via 12.12.12.6 (2297856/128256), Serial1/2

的度量值为（即R1->R2->R3->3.3.3.3的通告距离）：AD=2297856。 而R1的Topology表中，路径R1->R4->R3->3.3.3.3 P 3.3.3.0/24, 1 successors, FD is 435200

via 12.12.12.10 (435200/409600), Ethernet0/0

的度量值为（即R1->R4->R3->3.3.3.3的可行性距离）：FD=435200。 这里AD>FD。因此路径R1->R2->R3没有进入R1的Topology表。

修改度量值

在R1上修改R1->R4->R3->3.3.3.3的度量值。

R1

r1#configure terminal r1(config)#router eigrp 1

r1(config-router)#offset-list 1 in 1862657 ethernet 0/0 r1(config-router)#exit r1(config)#exit

显示R1的topology表和路由表

r1#show ip route

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

1.0.0.0/24 is subnetted, 1 subnets

C 1.1.1.0 is directly connected, Loopback0 2.0.0.0/24 is subnetted, 1 subnets

D 2.2.2.0 [90/2297856] via 12.12.12.2, 00:20:13, Serial1/2

3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/2297857] via 12.12.12.10, 00:05:31, Ethernet0/0 4.0.0.0/24 is subnetted, 1 subnets

D 4.4.4.0 [90/2272257] via 12.12.12.10, 00:05:31, Ethernet0/0 12.0.0.0/30 is subnetted, 4 subnets

D 12.12.12.12 [90/2169857] via 12.12.12.10, 00:05:31, Ethernet0/0 C 12.12.12.8 is directly connected, Ethernet0/0

D 12.12.12.4 [90/2681856] via 12.12.12.2, 00:05:31, Serial1/2 C 12.12.12.0 is directly connected, Serial1/2 r1#show ipeigrp topology

IP-EIGRP Topology Table for AS(1)/ID(1.1.1.1)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status

P 12.12.12.12/30, 1 successors, FD is 2169857 via 12.12.12.10 (2169857/2144257), Ethernet0/0 P 1.1.1.0/24, 1 successors, FD is 128256 via Connected, Loopback0

P 2.2.2.0/24, 1 successors, FD is 2297856 via 12.12.12.2 (2297856/128256), Serial1/2 P 3.3.3.0/24, 1 successors, FD is 2297857

via 12.12.12.10 (2297857/2272257), Ethernet0/0 via 12.12.12.2 (2809856/2297856), Serial1/2 P 4.4.4.0/24, 1 successors, FD is 2272257

via 12.12.12.10 (2272257/1990913), Ethernet0/0 P 12.12.12.8/30, 1 successors, FD is 281600 via Connected, Ethernet0/0

P 12.12.12.4/30, 1 successors, FD is 2221056 via 12.12.12.2 (2681856/2169856), Serial1/2 P 12.12.12.0/30, 1 successors, FD is 2169856 via Connected, Serial1/2

topology表中出现路由条目：

P 3.3.3.0/24, 1 successors, FD is 2297857

via 12.12.12.10 (2297857/2272257), Ethernet0/0 via 12.12.12.2 (2809856/2297856), Serial1/2

现在两条路由条目都已经在Topology表中了。 但是路由表中仍然只有一条路由： 3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/2297857] via 12.12.12.10, 00:05:31, Ethernet0/0

做非等价负载均衡

R1

r1#configure terminal r1(config)#router eigrp 1 r1(config-router)#variance 2 r1(config-router)#exit r1(config)#exit

显示路由表

r1#show ip route

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

1.0.0.0/24 is subnetted, 1 subnets

C 1.1.1.0 is directly connected, Loopback0 2.0.0.0/24 is subnetted, 1 subnets

D 2.2.2.0 [90/2297856] via 12.12.12.2, 00:01:46, Serial1/2 3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/2297857] via 12.12.12.10, 00:01:46, Ethernet0/0 [90/2809856] via 12.12.12.2, 00:01:46, Serial1/2 4.0.0.0/24 is subnetted, 1 subnets

D 4.4.4.0 [90/2272257] via 12.12.12.10, 00:01:46, Ethernet0/0 12.0.0.0/30 is subnetted, 4 subnets

D 12.12.12.12 [90/2169857] via 12.12.12.10, 00:01:46, Ethernet0/0 C 12.12.12.8 is directly connected, Ethernet0/0

D 12.12.12.4 [90/2681856] via 12.12.12.2, 00:01:46, Serial1/2 C 12.12.12.0 is directly connected, Serial1/2 这里出现了路由条目：

3.0.0.0/24 is subnetted, 1 subnets

D 3.3.3.0 [90/2297857] via 12.12.12.10, 00:01:46, Ethernet0/0 [90/2809856] via 12.12.12.2, 00:01:46, Serial1/2

显然：现在到3.3.3.3在路由表中存在有2条路由，他们是按照2：1的形式进行工作的。即从Ethernet0/0出去两个数据包，从Serial1/2出去一个数据包。

说明：

要做到非等价负载均衡的首要条件是两条路由都在路由器的Topology表中。即：满足DUAL算法（次要路径的通告距离AD<主路径的可行性距离FD）。