BSCI—2:EIGRP非等價負載均衡
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在做實驗之前我想先解釋一下實現EIGRP負載的一些知識(圖)!
一:思考
如果R1想去去往R5的話,那麼它面臨着有3條路可以走,但是我們可以請注意到,3條路的度量值是不一樣的,所以度量值不一樣即不能實現負載均衡,於是R1就會選擇R3做爲它的下一跳,把它放入路由表當中,那我們怎樣實現非等價負載呢(即帶寬不一致的情況)?
二:術語
AD(Advertise Distance):宣告距離 (鄰居到某網絡的距離)
FD (Feasible Distance):可行距離 (自己到某網絡的距離)
如圖所示: 如果R1從R3到R5,那麼它的AD=10,FD=20.
注:這個一定得搞清,不然接下來都不知道我講什麼.
三:條件
1. 如果我在R1配置R1(config-router)#variance 2的話,那麼R2會做爲R1的另一條去住R5的路徑,因爲2*(FD)>(20+10=30),即從R2到R5的FD小於R3到R5的FD,所以才能實現負載.
2.如果我variance設置爲3的話,那麼按我剛剛所說的從R4到R5的FD也小於2*(FD),那它會被加入的負載路徑裏面去嗎?答案肯定不會,因爲還有一個條件就是AD必需小於FD,從R4到R5的AD爲25,而從R3到R5的FD爲20,所以不滿足,不能實現負載.
實驗:拓撲如下
注:首先說明一下,由於51CTO只允許寫8萬字,所以步驟一隻寫了R1的配置,其它一樣
步驟一:首先先把所以接口信息以及EIGRP全部啓用,並且查看信息.
R1:
Router>
Router>en
Router#conf t
Router(config)#hostname R1
R1(config)#interface f0/0
R1(config-if)#ip address 192.168.12.1 255.255.255.0
R1(config-if)#no sh
R1(config-if)#ip address 192.168.13.1 255.255.255.0
R1(config-if)#no sh
R1(config-if)#exit
R1(config)#router eigrp 1
R1(config-router)#no auto-summary
R1(config-router)#network 192.168.12.0 0.0.0.255
R1(config-router)#network 192.168.13.0 0.0.0.255
R1(config-if)#end
R1#
R1上查看路由表:
R1#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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
4.0.0.0/24 is subnetted, 1 subnets
D 4.4.4.0 [90/158720] via 192.168.13.2, 00:00:06, FastEthernet0/1
[90/158720] via 192.168.12.2, 00:00:06, FastEthernet0/0
C 192.168.12.0/24 is directly connected, FastEthernet0/0
C 192.168.13.0/24 is directly connected, FastEthernet0/1
D 192.168.24.0/24 [90/30720] via 192.168.12.2, 00:04:00, FastEthernet0/0
D 192.168.34.0/24 [90/30720] via 192.168.13.2, 00:03:50, FastEthernet0/1
R1#
注:很清楚的看到,去往4.4.4.4有兩條路可以走,因爲其度量值一樣,EIGRP自動實現負載均衡,
步驟二:R1設置F0/1接口帶寬爲512KB,其兩邊度量值不一樣,使得所以數據只向F0/0轉發,產查看路由表與拓撲表.
R1(config)#interface f0/1
R1(config-if)#bandwidth 512
R1(config-if)#end
R1#
查看路由表:
R1#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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
4.0.0.0/24 is subnetted, 1 subnets
D 4.4.4.0 [90/158720] via 192.168.12.2, 00:08:43, FastEthernet0/0
C 192.168.12.0/24 is directly connected, FastEthernet0/0
C 192.168.13.0/24 is directly connected, FastEthernet0/1
D 192.168.24.0/24 [90/30720] via 192.168.12.2, 00:12:37, FastEthernet0/0
D 192.168.34.0/24 [90/33280] via 192.168.12.2, 00:01:04, FastEthernet0/0
R1#
//這裏因爲改變F0/1了帶寬,所以去住4.4.4.4全部往F0/0轉發.只有一條.
步驟三:實現非等價負載均衡
R1(config)#router eigrp 1
R1(config-router)#variance 32 // 32=5133056除以158720,滿足條件.
查看路由表:
R1#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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
4.0.0.0/24 is subnetted, 1 subnets
D 4.4.4.0 [90/5133056] via 192.168.13.2, 00:00:02, FastEthernet0/1
[90/158720] via 192.168.12.2, 00:00:01, FastEthernet0/0
C 192.168.12.0/24 is directly connected, FastEthernet0/0
C 192.168.13.0/24 is directly connected, FastEthernet0/1
D 192.168.24.0/24 [90/30720] via 192.168.12.2, 00:00:01, FastEthernet0/0
D 192.168.34.0/24 [90/30720] via 192.168.13.2, 00:00:02, FastEthernet0/1
R1#
// 去往4.4.4.4的路由,又變成了兩條.
實驗完畢. |