1、 双ISP接入负载均衡NAT与IP SLA链路检测实验配置 CE路由器为企业边缘路由器,f0/0,f2/0分别为ISP1,ISP2接口做负载均衡,loopback0接口模拟内部主机。内部流量负载均衡到ISP1与ISP2两条链路上,为模拟出负载均衡流量,CE的loopback0、f0/0、f2/0接口上禁用了快速交换(ip route cache)以及CEF并启用了基于per-packet的负载均衡(ip load-sharing per-packet)。通过在CE路由器上配置IP SLA来检测ISP链路的可用性。Internet-server路由器的loopback0接口模拟interne
2、t上的某个server,并且此server也是双ISP接入。 CE configuration CE#sh run Building configuration... Current configuration : 2288 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname CE ! boot-start-marker boot-
3、end-marker ! ! no aaa new-model memory-size iomem 5 ! ! ip cef no ip domain lookup ! ! ip sla monitor 1 type echo protocol ipIcmpEcho 172.16.2.1 source-interface FastEthernet0/0 ip sla monitor schedule 1 life forever start-time now ip sla monitor 2 type echo protocol ipIcmpEcho 172.
4、31.2.1 source-interface FastEthernet2/0 ip sla monitor schedule 2 life forever start-time now ! ! ! ! track 1 rtr 1 reachability #将track与ip sla 关联起来,track根据ip sla的返回代码来断定链路UP/DOWN ! track 2 rtr 2 reachability ! ! ! ! ! interface Loopback0 ip address 1.1.1.1 255.255.255.255
5、 ip load-sharing per-packet ip nat inside ip virtual-reassembly no ip route-cache cef no ip route-cache ! interface FastEthernet0/0 description isp1 ip address 172.16.1.1 255.255.255.0 ip load-sharing per-packet ip nat outside ip virtual-reassembly no ip route-cache cef no ip
6、 route-cache duplex auto speed auto ! interface Serial1/0 no ip address shutdown serial restart-delay 0 ! interface Serial1/1 no ip address shutdown serial restart-delay 0 ! interface Serial1/2 no ip address shutdown serial restart-delay 0 ! interface Serial1/3 no ip
7、address shutdown serial restart-delay 0 ! interface FastEthernet2/0 description isp2 ip address 172.31.1.1 255.255.255.0 ip load-sharing per-packet ip nat outside ip virtual-reassembly no ip route-cache cef no ip route-cache duplex auto speed auto ! ip http server no ip ht
8、tp secure-server ! ip route 0.0.0.0 0.0.0.0 FastEthernet0/0 172.16.1.2 track 1 #根据track reachability状态UP/DOWN默认路由 ip route 0.0.0.0 0.0.0.0 FastEthernet2/0 172.31.1.2 track 2 ip route 172.16.2.1 255.255.255.255 FastEthernet0/0 #首先解决IP SLA 检测目标的路由,而后默认路由才能UP ip route 172.31.2.1 255.255.255.2
9、55 FastEthernet2/0 ! ip nat inside source route-map isp1 interface FastEthernet0/0 overload ip nat inside source route-map isp2 interface FastEthernet2/0 overload #通过使用route map来匹配数据包的路由出接口 ! access-list 1 permit 1.1.1.1 access-list 100 permit ip host 1.1.1.1 host 3.3.3.3 # 此ACL仅用于debug调试
10、 ! route-map isp2 permit 10 match ip address 1 match interface FastEthernet2/0 ! route-map isp1 permit 10 match ip address 1 match interface FastEthernet0/0 ! ! control-plane ! ! ! ! ! ! ! ! ! ! line con 0 logging synchronous line aux 0 line vty 0 4 login
11、 ! ! End ISP1 configuration ISP1#sh run Building configuration... Current configuration : 955 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname ISP1 ! boot-start-marker boot-end-marker !
12、 ! no aaa new-model ! resource policy ! ip cef ! ! ! ! no ip domain lookup ! ! ! ! ! ! ! ! ! ! interface FastEthernet0/0 ip address 172.16.1.2 255.255.255.0 duplex half ! interface Serial1/0 no ip address shutdown serial restart-delay 0 ! interface Serial1/1 ip a
13、ddress 172.16.2.2 255.255.255.0 serial restart-delay 0 ! interface Serial1/2 no ip address shutdown serial restart-delay 0 ! interface Serial1/3 no ip address shutdown serial restart-delay 0 ! interface FastEthernet2/0 no ip address shutdown duplex half ! ip route 3.3.3.3
14、 255.255.255.255 Serial1/1 no ip http server no ip http secure-server ! ! ! logging alarm informational ! ! ! ! ! control-plane ! ! line con 0 logging synchronous stopbits 1 line aux 0 stopbits 1 line vty 0 4 login ! ! End ISP2 configuration ISP2#sh run Building conf
15、iguration... Current configuration : 955 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname ISP2 ! boot-start-marker boot-end-marker ! ! no aaa new-model ! resource policy ! ip cef ! ! ! !
16、 no ip domain lookup ! ! ! ! ! ! ! ! ! ! interface FastEthernet0/0 no ip address shutdown duplex half ! interface Serial1/0 ip address 172.31.2.2 255.255.255.0 serial restart-delay 0 ! interface Serial1/1 no ip address shutdown serial restart-delay 0 ! interface Ser
17、ial1/2 no ip address shutdown serial restart-delay 0 ! interface Serial1/3 no ip address shutdown serial restart-delay 0 ! interface FastEthernet2/0 ip address 172.31.1.2 255.255.255.0 duplex half ! ip route 3.3.3.3 255.255.255.255 Serial1/0 no ip http server no ip http secur
18、e-server ! ! ! logging alarm informational ! ! ! ! ! control-plane ! ! line con 0 logging synchronous stopbits 1 line aux 0 stopbits 1 line vty 0 4 login ! ! End Internet-server configuration Internet-server#sh run Building configuration... Current configuration : 1
19、065 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname Internet-server ! boot-start-marker boot-end-marker ! ! no aaa new-model ! resource policy ! ip cef ! ! ! ! no ip domain lookup ! !
20、 ! ! ! ! ! ! ! interface Loopback0 ip address 3.3.3.3 255.255.255.255 ! interface FastEthernet0/0 no ip address shutdown duplex half ! interface Serial1/0 ip address 172.16.2.1 255.255.255.0 serial restart-delay 0 ! interface Serial1/1 ip address 172.31.2.1 255.255.255.0
21、 serial restart-delay 0 ! interface Serial1/2 no ip address shutdown serial restart-delay 0 ! interface Serial1/3 no ip address shutdown serial restart-delay 0 ! interface FastEthernet2/0 no ip address shutdown duplex half ! ip route 172.16.0.0 255.255.0.0 Serial1/0 ip r
22、oute 172.31.0.0 255.255.0.0 Serial1/1 no ip http server no ip http secure-server ! ! ! logging alarm informational ! ! ! ! ! control-plane ! ! line con 0 logging synchronous stopbits 1 line aux 0 stopbits 1 line vty 0 4 login ! ! End Show信息 Debug测试 走F2/0的包,源IP被NAT成ISP2接口IP 走F0/0的包,源IP被NAT成ISP1接口IP Shutdown internet-server路由器的S1/0接口,测试IP SLA 由于IP SLA monitor 1 检测目标ping不同,ISP1的默认路由DOWN掉,只剩下ISP2的默认路由 IP SLA monitor 1 return code为timeout,track 1 reachability为down,因此ISP1默认路由DOWN掉






