China Telecom and China Unicom dual-line access

China Unicom's dual-line access has recently added a new line to the customer (previously using China Unicom). We need to perform dual-line load balancing to access the China Unicom website.
China Telecom line. Here, let's take a look at how to implement this function on a cisco router, such as: Eg:
Topology Description: R3 is the company's vrof0 F0/1 connected to the Intranet, NAT internal address on the internet, R1, R4 simulate the telecom external network, R2, R5 Simulation
Connect external networks. Basic configuration of www.2cto.com R3 interface: interface FastEthernet0/1 ip address 192.168.1.1 255.255.255.0 description R1 LAN ip nat inside interface FastEthernet1/1 ip address 21.21.21.1 255.255.255.0 description R1 ----> ISP1 ip nat outside interface FastEthernet1/0 ip address 12.12.12.1 255.255.255.0 description R1 ----> ISP1 ip nat outside ====================================== ==== R1 Interface Configuration: interface FastEthernet1/0 ip address 12.12.2 255.255.255.0 interface FastEthernet1/1 ip address 14.14.14.1 255.255.0 ================ =================== R2 Interface Configuration: interface FastEthernet1/0 ip address 21.21.21.2 255.255.255.0 interface FastEthernet1/1 ip address 25.25.25.1 255.255.255.0 ============ ======================= 1. configure the NAT list: access-list 100 permit ip 192.168.1.0 0.0.255 any www.2cto.com 2. configure a dynamic address pool: ip nat pool isp1 12.12.12.1 12.12.1 netmask 255.255.255.255.0ip nat pool isp2 21.21.21.1 21.21.21.1 netmask 255.255.255.03. configure the routing policy: route-map isp2 permit 1 match ip address 100 match interface FastEthernet1/0 route-map isp1 permit 1 match ip address 100 match interface FastEthernet1/1 4. configure ip sla: ip sla 1 icmp-echo 12.12.12.2 source-ip 12.12.1 frequency 20ip sla schedule 1 life forever start-time now ip sla 2 icmp-echo 21.21.21.2 source-ip 21.21.21.1 frequency 20ip sla schedule 2 life forever start-time now track 10 ip sla 1 reachabilitytrack 20 ip sla 2 reachability 5. ing NAT list: ip nat inside source route-map isp1 pool isp1 overloadip nat inside source route-map isp2 pool isp2 overload 6. route configuration: ip route 0.0.0.0 0.0.0.0 12.12.12.2 track 10 ip route 0.0.0.0 0.0.0.0 21.21.21.2 track 20 -------- achieves dual-line redundancy with sla, by default, the cisco router is verified based on the target address Server Load balancer www.2cto.com ip route 25.25.25.0 255.255.0 21.21.21.2 -------- adding all the China Unicom CIDR blocks to the static route table when accessing the China Unicom network.: r3 # show ip routeGateway of last resort is 21.21.21.2 to network 0.0.0.0 21.0.0.0/24 is subnetted, 1 subnetsC 21.21.21.0 is directly connected, FastEthernet1/0 12.0.0.0/24 is subnetted, 1 subnetsC 12.12.0 is directly connected, FastEthernet1/1C 192.168.1.0/24 is directly connected, loopback1S * 0.0.0.0/0 [1/0] via 21.21.21.2 ----------------- display two default routes [1/0] via 12.12.12.2 R3 # traceroute 25.25.25.2 source 192.168.1.1Type escape sequence to abort. tracing the route to 25.25.25.2 www.2cto.com 1 21.21.21.2 40 msec 76 msec 60 msec ------ From the UNICOM road out of the Internet 2 25.25.25.2 80 msec * 76 msec appendix: china Unicom public IP address list 110.16.0.0/latest/15110.6.0.0/latest/15113.0.0.0/13113.194.0.0/15113.200.0.0/15113.204.0.0/ release/release/17113.8.0.0/release/15116.2.0.0/release/16117.8.0.0/13118.212.0.0/release/15119.112.0.0/13119.162.0.0/ container/14119.176.0.0/12119.248.0.0/latest/16119.4.0.0/latest/16120.0.0.0/latest/13121.16.0.0/latest/15123.112.0.0/ latest/13123.138.0.0/15123.144.0.0/14123.148.0.0/16123.152.0.0/latest/14123.4.0.0/14123.8.0.0/latest/ latest/latest/15124.92.0.0/14125.211.0.0/latest/14125.40.0.0/13175.42.0.0/latest/20202.106.0.0/16202.107.0.0/ 17202.108.0.0/16202.110.0.0/latest/24202.96.0.0/latest/20202.98.0.0/latest/21202.99.0.0/latest/ latest/latest/19202.99.160.0/latest/21202.99.176.0/latest/24210.13.0.0/latest/17210.13.64.0/18210.14.160.0/ 19210.14.192.0/latest/18210.15.32.0/19210.15.96.0/latest/15211.144.0.0/latest/15211.94.0.0/15211.96./ 0.0/ 15218.10.0.0/latest/19218.105.0.0/16218.106.0.0/15218.11.0.0/16218.12.0.0/latest/ tests/tests/18220.192.0.0/15220.194.0.0/tests/16221.0.0.0/15221.10.0.0/16221.11.0.0/tests/18221.11.192.0/tests/ 19221.12.0.0/latest/18221.13.0.0/latest/17221.13.64.0/latest/19221.14.0.0/latest/16221.199.0.0/latest/18221.2.0.0/ container/14221.204.0.0/15221.206.0.0/latest/13221.3.0.0/latest/17221.4.0.0/16221.5.0.0/latest/17221.6.0.0/16221.7.0.0/latest/ latest/latest/19221.8.0.0/latest/13221_0.0.0/15221_2.0.0/16221_3.0.0/latest/17221_3.32.0/latest/1658.16.0.0/latest/1658.0.0/latest/ container/1558.240.0.0/1558.242.0.0/1558.244.0.0/1558.246.0.0/1558.248.0.0/latest/1360.10.0.0/1660.11.0.0/latest/ container/1560.30.0.0/latest/1660.8.0.0/1561.133.0.0/latest/1961.135.0.0/1661.136.0.0/latest/1761.138.0.0/latest/1861.148.0.0/1561. 156.0.0/1661.158.0.0/latest/1761.159.0.0/1861.161.0.0/latest/1761.181.0.0/latest/1461.52.0.0/latest/ author: 1661.55.0.0/16 luosongtao