青菜 2007-11-12 11:50
EIGRP非等成本的负载均衡
[align=center][size=3][font=Times New Roman]EIGRP[/font][font=宋体]非等成本的负载均衡[/font][/size][/align]
[align=center][size=3][font=Times New Roman] [/font][font=宋体]——验证新版本[/font][font=Times New Roman]IOS[/font][font=宋体]的“四舍五入”改进[/font][/size][/align]
[font=Times New Roman][size=3] [/size][/font]
[font=宋体][size=3]一、实验拓扑图：[/size][/font]
[align=center][size=3][/size][table=98%][tr][td][img=539,225]http://www.one-tom.com/bbs/uploads/20070329_104530_topu.JPG[/img]
[/td][/tr][/table][font=Times New Roman][size=3][/size][/font][table=98%][tr][td]
[/td][/tr][/table][size=3][font=Times New Roman][/font][/size][/align]
[font=宋体][size=3]二、实验目的：[/size][/font]
[size=3][font=Times New Roman] [/font][font=宋体]为了验证[/font][font=Times New Roman]EIGRP[/font][font=宋体]在[/font][font=Times New Roman]Cisco[/font][font=宋体]较新版本的[/font][font=Times New Roman]IOS[/font][font=宋体]中，将链路开销的比值四舍五入的进行负载均衡传输，我们将链路的开销修改为[/font][font=Times New Roman]1:1.65[/font][font=宋体]（其他也可以）。在[/font][font=Times New Roman]R2[/font][font=宋体]的两个接口上采用访问控制链表的方式进行抓包验证，也可以通过在[/font][font=Times New Roman]R1[/font][font=宋体]路由器上通过[/font][font=Times New Roman]show ip route 2.2.2.2[/font][font=宋体]查看发包的顺序。[/font][/size]
[size=3][font=Times New Roman] [/font][font=宋体]实验还要验证一个细节：[/font][font=Times New Roman]Cisco[/font][font=宋体]的不同版本的[/font][font=Times New Roman]IOS[/font][font=宋体]对[/font][font=Times New Roman]EIGRP[/font][font=宋体]关于非等开销的负载均衡处理方式是不同的。[/font][/size]
[font=宋体][size=3]三、具体配置：[/size][/font]
[table][tr][td=1,1,284][font=Times New Roman]R1[/font]
[/td][td=1,1,284][font=Times New Roman]R2[/font]
[/td][/tr][tr][td=1,1,284][font=Times New Roman]![/font]
[b][color=red][font=Times New Roman]no ip cef[/font][/color][/b]
[font=Times New Roman]![/font]
[font=Times New Roman]interface Loopback0[/font]
[font=Times New Roman]
ip address 1.1.1.1 255.255.255.0[/font]
[font=Times New Roman]![/font]
[font=Times New Roman]interface FastEthernet0/0[/font]
[font=Times New Roman]
ip address 20.0.0.1 255.255.255.0[/font]
[font=Times New Roman]
delay 14262[/font]
[font=Times New Roman]
duplex half[/font]
[font=Times New Roman]![/font]
[font=Times New Roman]interface Serial1/0[/font]
[font=Times New Roman]
ip address 10.0.0.1 255.255.255.0[/font]
[font=Times New Roman]
no ip route-cache[/font]
[font=Times New Roman]
serial restart-delay 0[/font]
[font=Times New Roman]……[/font]
[font=Times New Roman]![/font]
[font=Times New Roman]router eigrp 10[/font]
[font=Times New Roman]
variance 3[/font]
[font=Times New Roman]
network 1.1.1.1 0.0.0.0[/font]
[font=Times New Roman]
network 10.0.0.0 0.0.0.255[/font]
[font=Times New Roman]no auto-summary[/font]
[/td][td=1,1,284][font=Times New Roman]![/font]
[font=Times New Roman]interface Loopback0[/font]
[font=Times New Roman]
ip address 2.2.2.2 255.255.255.0[/font]
[font=Times New Roman]![/font]
[font=Times New Roman]interface FastEthernet0/0[/font]
[font=Times New Roman]
ip address 20.0.0.2 255.255.255.0[/font]
[font=Times New Roman]
ip access-group 20 in[/font]
[font=Times New Roman]
delay 142620[/font]
[font=Times New Roman]
duplex half[/font]
[font=Times New Roman]![/font]
[font=Times New Roman]interface Serial1/1[/font]
[font=Times New Roman]
ip address 10.0.0.2 255.255.255.0[/font]
[font=Times New Roman]
ip access-group 10 in[/font]
[font=Times New Roman]
serial restart-delay 0[/font]
[font=Times New Roman]![/font]
[font=Times New Roman]router eigrp 10[/font]
[font=Times New Roman]
variance 3[/font]
[font=Times New Roman]
network 2.2.2.2 0.0.0.0[/font]
[font=Times New Roman]
network 10.0.0.0 0.0.0.255[/font]
[font=Times New Roman]
network 20.0.0.0 0.0.0.255[/font]
[font=Times New Roman]
network 30.0.0.0 0.0.0.255[/font]
[font=Times New Roman]
no auto-summary[/font]
[/td][/tr][/table][size=3][font=Times New Roman] [/font][b][font=宋体][size=12pt]注意：在[/size][/font][/b][b][size=12pt][font=Times New Roman]R1[/font][/size][/b][b][font=宋体][size=12pt]中红字标识的配置尤为重要，本人就是因为没有想起来这点，直接导致整整搞了将近[/size][/font][/b][b][size=12pt][font=Times New Roman]5[/font][/size][/b][b][font=宋体][size=12pt]个小时的这个“可恶”的负载均衡，闲话不说，[/size][/font][color=red][font=Times New Roman]no ip cef[/font][/color][/b][/size]
[b][font=宋体][size=12pt]这个命令的作用是关闭路由器的快速转发功能，禁用[/size][/font][/b][b][size=12pt][font=Times New Roman]CEF[/font][/size][/b][b][font=宋体][size=12pt]快速转发，也就是说，这个[/size][/font][/b][b][size=12pt][font=Times New Roman]CEF[/font][/size][/b][b][font=宋体][size=12pt]中保存着和路由表一样的信息，当有包要发的时候路由器首先查询[/size][/font][/b][b][size=12pt][font=Times New Roman]CEF[/font][/size][/b][b][font=宋体][size=12pt]缓存，如果有同样的条目，则根据转发记录直接转发，而并不通过路由器的路由表，所以也就代表着，如果不关闭这个[/size][/font][/b][b][size=12pt][font=Times New Roman]CEF[/font][/size][/b][b][font=宋体][size=12pt]，包永远从一个端口转发，而达不到负载均衡的效果。切记。。。。。。[/size][/font][/b][b][size=12pt][/size][/b]
[b][size=12pt][font=Times New Roman] [/font][/size][/b]
[size=3][font=宋体]四、实验现象：[/font][size=10.5pt][/size][/size]
[size=3][color=red][font=Times New Roman]1[/font][/color][color=red][font=宋体]．[/font][/color][color=red][font=Times New Roman]IOS[/font][/color][color=red][font=宋体]版本[/font][/color][color=red][font=Times New Roman]7200 12.3 [/font][/color][color=red][font=宋体]或者[/font][/color][color=red][font=Times New Roman] 12.2(T)[/font][/color][/size]
[table][tr][td=1,1,568][size=10.5pt][font=Times New Roman]R1#sh ip rou[/font][/size]
[size=10.5pt][font=Times New Roman] [/font][/size]
[size=10.5pt][font=Times New Roman]Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BG[/font][/size]
[size=10.5pt][font=Times New Roman]
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area [/font][/size]
[size=10.5pt][font=Times New Roman]
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2[/font][/size]
[size=10.5pt][font=Times New Roman]
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP[/font][/size]
[size=10.5pt][font=Times New Roman]
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area[/font][/size]
[size=10.5pt][font=Times New Roman]
* - candidate default, U - per-user static route, o - ODR[/font][/size]
[size=10.5pt][font=Times New Roman]
P - periodic downloaded static route[/font][/size]
[size=10.5pt][font=Times New Roman]Gateway of last resort is not set[/font][/size]
[size=10.5pt][font=Times New Roman]
1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks[/font][/size]
[size=10.5pt][font=Times New Roman]D
1.0.0.0/8 is a summary, 00:24:09, Null0[/font][/size]
[size=10.5pt][font=Times New Roman]C
1.1.1.0/24 is directly connected, Loopback0[/font][/size]
[color=red][size=10.5pt][font=Times New Roman]D
2.0.0.0/8 [90/2297856] via 10.0.0.2, 00:21:54, Serial1/0[/font][/size][/color]
[color=red][size=10.5pt][font=Times New Roman]
[90/3810560] via 20.0.0.2, 00:21:54, Ethernet0/0[/font][/size][/color]
[size=10.5pt][font=Times New Roman]
20.0.0.0/8 is variably subnetted, 2 subnets, 2 masks[/font][/size]
[size=10.5pt][font=Times New Roman]D
20.0.0.0/8 is a summary, 00:22:04, Null0[/font][/size]
[size=10.5pt][font=Times New Roman]C
20.0.0.0/24 is directly connected, Ethernet0/0[/font][/size]
[size=10.5pt][font=Times New Roman]
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks[/font][/size]
[size=10.5pt][font=Times New Roman]D
10.0.0.0/8 is a summary, 00:21:54, Null0[/font][/size]
[size=10.5pt][font=Times New Roman]C
10.0.0.0/24 is directly connected, Serial1/0[/font][/size]
[/td][/tr][/table][size=10.5pt][font=Times New Roman][size=3] [/size][/font][/size]
[table][tr][td=1,1,568][size=10.5pt][font=Times New Roman]R1# sh ip ei to[/font][/size]
[size=10.5pt][font=Times New Roman] [/font][/size]
[size=10.5pt][font=Times New Roman]IP-EIGRP Topology Table for AS(10)/ID(1.1.1.1)[/font][/size]
[size=10.5pt][font=Times New Roman]Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,[/font][/size]
[size=10.5pt][font=Times New Roman]
r - reply Status, s - sia Status [/font][/size]
[font=Times New Roman][size=10.5pt]P 1.0.0[/size][size=10.5pt].0/8, 1 successors, FD is 128256[/size][/font]
[size=10.5pt][font=Times New Roman]
via Summary (128256/0), Null0[/font][/size]
[font=Times New Roman][size=10.5pt]P 1.1.1[/size][size=10.5pt].0/24, 1 successors, FD is 128256[/size][/font]
[size=10.5pt][font=Times New Roman]
via Connected, Loopback0[/font][/size]
[font=Times New Roman][color=red][size=10.5pt]P 2.0.0[/size][/color][color=red][size=10.5pt].0/8, 1 successors, FD is 409600[/size][/color][/font]
[color=red][size=10.5pt][font=Times New Roman]
via 10.0.0.2 (2297856/128256), Serial1/0[/font][/size][/color]
[color=red][size=10.5pt][font=Times New Roman]
via 20.0.0.2 (3810560/128256), Ethernet0/0[/font][/size][/color]
[font=Times New Roman][size=10.5pt]P 10.0.0[/size][size=10.5pt].0/8, 1 successors, FD is 2169856[/size][/font]
[size=10.5pt][font=Times New Roman]
via Summary (2169856/0), Null0[/font][/size]
[font=Times New Roman][size=10.5pt]P 10.0.0[/size][size=10.5pt].0/24, 1 successors, FD is 2169856[/size][/font]
[size=10.5pt][font=Times New Roman]
via Connected, Serial1/0[/font][/size]
[font=Times New Roman][size=10.5pt]P 20.0.0[/size][size=10.5pt].0/8, 1 successors, FD is 2870016[/size][/font]
[size=10.5pt][font=Times New Roman]
via Summary (3682560/0), Null0[/font][/size]
[size=10.5pt][font=Times New Roman]
via 10.0.0.2 (2195456/281600), Serial1/0[/font][/size]
[font=Times New Roman][size=10.5pt]P 20.0.0[/size][size=10.5pt].0/24, 1 successors, FD is 3682560[/size][/font]
[size=10.5pt][font=Times New Roman]
via Connected, Ethernet0/0[/font][/size]
[/td][/tr][/table][size=10.5pt][font=Times New Roman][size=3] [/size][/font][/size]
[table][tr][td=1,1,568][size=10.5pt][font=Times New Roman]R1#sh ip rou 2.2.2.2[/font][/size]
[size=10.5pt][font=Times New Roman]Routing entry for 2.0.0.0/8[/font][/size]
[size=10.5pt][font=Times New Roman]
Known via "eigrp 10", distance 90, metric 2297856, type internal[/font][/size]
[size=10.5pt][font=Times New Roman]
Redistributing via eigrp 10[/font][/size]
[size=10.5pt][font=Times New Roman]
Last update from 20.0.0.2 on Ethernet0/0, 00:22:29 ago[/font][/size]
[size=10.5pt][font=Times New Roman]
Routing Descriptor Blocks:[/font][/size]
[size=10.5pt][font=Times New Roman]
10.0.0.2, from 10.0.0.2, 00:22:29 ago, via Serial1/0[/font][/size]
[font=Times New Roman][size=10.5pt]
Route metric is 2297856,[color=red] traffic share count is [/color][/size][b][size=14pt]2[/size][/b][size=10.5pt][/size][/font]
[size=10.5pt][font=Times New Roman]
Total delay is 25000 microseconds, minimum bandwidth is 1544 Kbit[/font][/size]
[size=10.5pt][font=Times New Roman]
Reliability 255/255, minimum MTU 1500 bytes[/font][/size]
[size=10.5pt][font=Times New Roman]
Loading 1/255, Hops 1[/font][/size]
[size=10.5pt][font=Times New Roman]
* 20.0.0.2, from 20.0.0.2, 00:22:29 ago, via Ethernet0/0[/font][/size]
[font=Times New Roman][size=10.5pt]
Route metric is 3810560, [color=red]traffic share count is[/color][/size][b][size=14pt] 1[/size][/b][size=10.5pt][/size][/font]
[size=10.5pt][font=Times New Roman]
Total delay is 6000 microseconds, minimum bandwidth is 700 Kbit[/font][/size]
[size=10.5pt][font=Times New Roman]
Reliability 255/255, minimum MTU 1500 bytes[/font][/size]
[size=10.5pt][font=Times New Roman]
Loading 1/255, Hops 1[/font][/size]
[/td][/tr][/table][size=10.5pt][font=Times New Roman][size=3] [/size][/font][/size]
[size=3][b][color=red][font=宋体]可以看到，同样的配置，到了这个版本的[/font][/color][/b][b][color=red][size=10.5pt][font=Times New Roman]IOS[/font][/size][/color][/b][b][color=red][font=宋体]下面就会被四舍五入为[/font][/color][/b][b][color=red][size=10.5pt][font=Times New Roman]1:2[/font][/size][/color][/b][/size]
[b][color=red][size=10.5pt][font=Times New Roman][size=3] [/size][/font][/size][/color][/b]
[size=3][font=宋体]这次用[/font][size=10.5pt][font=Times New Roman]IOS[/font][/size][font=宋体]版本为[/font][size=10.5pt][font=Times New Roman]12.4[/font][/size][/size]
[table][tr][td=1,1,568][size=10.5pt][font=Times New Roman]R1#sh ip ei 10 to[/font][/size]
[size=10.5pt][font=Times New Roman]IP-EIGRP Topology Table for AS(10)/ID(1.1.1.1)[/font][/size]
[size=10.5pt][font=Times New Roman] [/font][/size]
[size=10.5pt][font=Times New Roman]Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,[/font][/size]
[size=10.5pt][font=Times New Roman]
r - reply Status, s - sia Status [/font][/size]
[size=10.5pt][font=Times New Roman] [/font][/size]
[font=Times New Roman][size=10.5pt]P 1.0.0[/size][size=10.5pt].0/8, 1 successors, FD is 128256[/size][/font]
[size=10.5pt][font=Times New Roman]
via Summary (128256/0), Null0[/font][/size]
[font=Times New Roman][size=10.5pt]P 1.1.1[/size][size=10.5pt].0/24, 1 successors, FD is 128256[/size][/font]
[size=10.5pt][font=Times New Roman]
via Connected, Loopback0[/font][/size]
[font=Times New Roman][color=red][size=10.5pt]P 2.0.0[/size][/color][color=red][size=10.5pt].0/8, 1 successors, FD is 156160[/size][/color][/font]
[color=red][size=10.5pt][font=Times New Roman]
via 10.0.0.2 (2297856/128256), Serial1/0[/font][/size][/color]
[color=red][size=10.5pt][font=Times New Roman]
via 20.0.0.2 (3787520/128256), FastEthernet0/0[/font][/size][/color]
[font=Times New Roman][size=10.5pt]P 10.0.0[/size][size=10.5pt].0/8, 1 successors, FD is 2169856[/size][/font]
[size=10.5pt][font=Times New Roman]
via Summary (2169856/0), Null0[/font][/size]
[font=Times New Roman][size=10.5pt]P 10.0.0[/size][size=10.5pt].0/24, 1 successors, FD is 2169856[/size][/font]
[size=10.5pt][font=Times New Roman]
via Connected, Serial1/0[/font][/size]
[font=Times New Roman][size=10.5pt]P 20.0.0[/size][size=10.5pt].0/8, 1 successors, FD is 3557888[/size][/font]
[size=10.5pt][font=Times New Roman]
via Summary (3659520/0), Null0[/font][/size]
[size=10.5pt][font=Times New Roman]
via 10.0.0.2 (2172416/28160), Serial1/0[/font][/size]
[font=Times New Roman][size=10.5pt]P 20.0.0[/size][size=10.5pt].0/24, 1 successors, FD is 3659520[/size][/font]
[size=10.5pt][font=Times New Roman]
via Connected, FastEthernet0/0[/font][/size]
[/td][/tr][/table][size=10.5pt][font=Times New Roman][size=3] [/size][/font][/size]
[table][tr][td=1,1,568][size=10.5pt][font=Times New Roman]R1#sh ip rou 2.2.2.2[/font][/size]
[size=10.5pt][font=Times New Roman]Routing entry for 2.0.0.0/8[/font][/size]
[size=10.5pt][font=Times New Roman]
Known via "eigrp 10", distance 90, metric 2297856, type internal[/font][/size]
[size=10.5pt][font=Times New Roman]
Redistributing via eigrp 10[/font][/size]
[size=10.5pt][font=Times New Roman]
Last update from 20.0.0.2 on FastEthernet0/0, 00:00:34 ago[/font][/size]
[size=10.5pt][font=Times New Roman]
Routing Descriptor Blocks:[/font][/size]
[size=10.5pt][font=Times New Roman]
* 20.0.0.2, from 20.0.0.2, 00:00:34 ago, via FastEthernet0/0[/font][/size]
[font=Times New Roman][size=10.5pt]
Route metric is 3787520, [color=red]traffic share count is [/color][/size][b][size=14pt]73[/size][/b][size=10.5pt][/size][/font]
[size=10.5pt][font=Times New Roman]
Total delay is 5100 microseconds, minimum bandwidth is 700 Kbit[/font][/size]
[size=10.5pt][font=Times New Roman]
Reliability 255/255, minimum MTU 1500 bytes[/font][/size]
[size=10.5pt][font=Times New Roman]
Loading 1/255, Hops 1[/font][/size]
[size=10.5pt][font=Times New Roman]
10.0.0.2, from 10.0.0.2, 00:00:34 ago, via Serial1/0[/font][/size]
[font=Times New Roman][size=10.5pt]
Route metric is 2297856, [color=red]traffic share count is[/color][/size][b][size=14pt] 120[/size][/b][size=10.5pt][/size][/font]
[size=10.5pt][font=Times New Roman]
Total delay is 25000 microseconds, minimum bandwidth is 1544 Kbit[/font][/size]
[size=10.5pt][font=Times New Roman]
Reliability 255/255, minimum MTU 1500 bytes[/font][/size]
[size=10.5pt][font=Times New Roman]
Loading 1/255, Hops 1[/font][/size]
[/td][/tr][/table][size=10.5pt][font=Times New Roman][size=3] [/size][/font][/size]
[size=3][font=宋体]！！注意：在[/font][size=10.5pt][font=Times New Roman]12.4[/font][/size][font=宋体]版本中这个比值不再四舍五入，但是否会无限制的扩大，我们可以设想，如果可以无限制的扩大，达到[/font][size=10.5pt][font=Times New Roman]999[/font][/size][font=宋体]：[/font][size=10.5pt][font=Times New Roman]1000[/font][/size][font=宋体]甚至更大，那么转发的方式是极不合理的，两条链路都会拥塞，我们改动一下[/font][size=10.5pt][font=Times New Roman]Fa0/0[/font][/size][font=宋体]口的带宽[/font][size=10.5pt][font=Times New Roman]Bandwidth [/font][/size][font=宋体]为[/font][size=10.5pt][font=Times New Roman]720[/font][/size][font=宋体]（之前为[/font][size=10.5pt][font=Times New Roman]700[/font][/size][font=宋体]）。[/font][size=10.5pt][/size][/size]
[table][tr][td=1,1,568][size=10.5pt][font=Times New Roman]R1#sh ip rou 2.2.2.2[/font][/size]
[size=10.5pt][font=Times New Roman]Routing entry for 2.0.0.0/8[/font][/size]
[size=10.5pt][font=Times New Roman]
Known via "eigrp 10", distance 90, metric[color=red] 2297856[/color], type internal[/font][/size]
[size=10.5pt][font=Times New Roman]
Redistributing via eigrp 10[/font][/size]
[size=10.5pt][font=Times New Roman]
Last update from 20.0.0.2 on FastEthernet0/0, 00:00:01 ago[/font][/size]
[size=10.5pt][font=Times New Roman]
Routing Descriptor Blocks:[/font][/size]
[size=10.5pt][font=Times New Roman]
* 20.0.0.2, from 20.0.0.2, 00:00:01 ago, via FastEthernet0/0[/font][/size]
[font=Times New Roman][size=10.5pt]
Route metric is 3685888, [color=red]traffic share count is [/color][/size][b][size=14pt]5[/size][/b][size=10.5pt][/size][/font]
[size=10.5pt][font=Times New Roman]
Total delay is 5100 microseconds, minimum bandwidth is 720 Kbit[/font][/size]
[size=10.5pt][font=Times New Roman]
Reliability 255/255, minimum MTU 1500 bytes[/font][/size]
[size=10.5pt][font=Times New Roman]
Loading 1/255, Hops 1[/font][/size]
[size=10.5pt][font=Times New Roman]
10.0.0.2, from 10.0.0.2, 00:00:01 ago, via Serial1/0[/font][/size]
[font=Times New Roman][size=10.5pt]
Route metric is[color=red] 2297856[/color], [color=red]traffic share count is[/color][/size][b][size=14pt] 8[/size][/b][size=10.5pt][/size][/font]
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Total delay is 25000 microseconds, minimum bandwidth is 1544 Kbit[/font][/size]
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Reliability 255/255, minimum MTU 1500 bytes[/font][/size]
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Loading 1/255, Hops 1[/font][/size]
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[size=3][color=red][font=宋体]可以很明显的看到，路由器对开销的比例做了处理，比[/font][/color][color=red][size=10.5pt][font=Times New Roman]12.2[/font][/size][/color][color=red][font=宋体]的版本更合理，将比值在更合理的范围内变得更加精细，是负载均衡更高效。。
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