本文主要描述通過策略路由PBR和IP服務(wù)水平協(xié)議SLA來實現(xiàn)數(shù)據(jù)包的分流。

假設(shè)：Outside上設(shè)置默認(rèn)路由到192.168.1.0/24，下一條指向R6：ip route 0.0.0.0 255.255.255.0 1.1.56.6
要求：但是從源IP:5.5.5.5/32出來的數(shù)據(jù)包必須走R4：并且保證鏈路的暢通性：

R5基本配置：
interface Loopback0
  ip address 5.5.5.5 255.255.255.255

interface FastEthernet1/0
  ip address 1.1.56.5 255.255.255.0

interface FastEthernet1/1
  ip address 1.1.45.5 255.255.255.0
  ip policy route-map AAA

ip local policy route-map AAA
ip route 0.0.0.0 0.0.0.0 1.1.56.6
route-map AAA permit 10
  match interface Loopback0
  set ip next-hop 1.1.45.4

R5#debug ip policy
R5#ping 4.4.4.4 sou lo0 ：這里注意：如果是本地產(chǎn)生的流量，route-map默認(rèn)是不匹配的，需要啟用：[ip local policy route-map AAA]：才能讓本地流量匹配AAA：

*Dec  3 18:48:32.823: IP: s=5.5.5.5 (local), d=4.4.4.4, len 100, policy match
*Dec  3 18:48:32.823: IP: route map AAA, item 10, permit
*Dec  3 18:48:32.827: IP: s=5.5.5.5 (local), d=4.4.4.4 (FastEthernet1/1), len 100, policy routed
*Dec  3 18:48:32.827: IP: local to FastEthernet1/1 1.1.45.4

此時如果關(guān)閉R4的F1/1接口：此時R5再pingR4：鏈路是否正常？
【不通】：解釋：route-map無法區(qū)分下一跳是否可達(dá)。但是可以結(jié)合SLA來實現(xiàn)：

ip sla monitor 1
type echo protocol ipIcmpEcho 1.1.45.4
frequency 10
ip sla monitor schedule 1 life forever start-time now

track 2 rtr 1
route-map AAA permit 10
match interface Loopback0
set ip next-hop verify-availability 1.1.45.4 1 track 2

R5#ping 4.4.4.4 sou lo0 ：這里注意：此時如果你關(guān)閉R4的F1/1，即使流量匹配了route-map，但是策略還是不會被執(zhí)行，走正常的路由表：詳細(xì)見以下debug信息
Wan30#debug ip policy
*Dec  3 18:49:42.115: IP: s=5.5.5.5 (local), d=4.4.4.4, len 100, policy match
*Dec  3 18:49:42.115: IP: route map AAA, item 10, permit
*Dec  3 18:49:42.115: IP: s=5.5.5.5 (local), d=4.4.4.4, len 100, policy rejected -- normal forwarding

通過以上配置實驗，數(shù)據(jù)包分流實現(xiàn)。

【編輯推薦】

1. 思科培訓(xùn)專區(qū)
2. CCNP備考：路由命令篇之EIGRP命令手冊
3. CCNP的實驗設(shè)備注意事項