CCNP知识重点：思科设备BGP路径属性配置.doc

CCNP知识重点：思科设备BGP路径属性配置BGP协议与传统的路由协议相比最大的优势在于可以通过调整BGP的属性值影响选路，今天的技术帖我们就给大家举例介绍思科设备BGP路径属性的配置。拓扑图如下图所示：(1)IGP协议配置/RTA配置RTA(config)#interface Loopback0RTA(config-if)#ip address 1.1.1.1 255.255.255.255RTA(config)#interface Loopback10RTA(config-if)#ip address 10.10.10.10 255.255.255.255RTA(config)#interface Ethernet0/0RTA(config-if)#ip address 100.1.1.1 255.255.255.0RTA(config)#interface Ethernet0/1RTA(config-if)#ip address 100.1.2.1 255.255.255.0/RTB配置RTB(config)#interface Loopback0RTB(config-if)#ip address 2.2.2.2 255.255.255.255RTB(config)#interface Ethernet0/0RTB(config-if)#ip address 100.1.1.2 255.255.255.0RTB(config)#interface Ethernet0/1RTB(config-if)#ip address 192.168.1.1 255.255.255.0RTB(config)#router ospf 110RTB(config-router)#router-id 2.2.2.2RTB(config-router)#network 2.2.2.2 0.0.0.0 area 0RTB(config-router)#network 192.168.1.0 0.0.0.255 area 0/RTC配置RTC(config)#interface Loopback0RTC(config-if)#ip address3.3.3.3255.255.255.255RTC(config)#interface Ethernet0/0RTC(config-if)#ip address 100.1.2.2 255.255.255.0RTC(config)#interface Ethernet0/1RTC(config-if)#ip address 192.168.2.1 255.255.255.0RTC(config)#router ospf 110RTC(config-router)#router-id3.3.3.3RTC(config-router)#network3.3.3.30.0.0.0 area 0RTC(config-router)#network 192.168.2.0 0.0.0.255 area 0/RTD配置RTD(config)#interface Loopback0RTD(config-if)#ip address 4.4.4.4 255.255.255.255RTD(config)#interface Loopback40RTD(config-if)#ip address 40.40.40.40 255.255.255.255RTD(config)#interface Ethernet0/0RTD(config-if)#ip address 192.168.2.2 255.255.255.0RTD(config)#interface Ethernet0/1RTD(config-if)#ip address 192.168.1.2 255.255.255.0RTD(config)#router ospf 110RTD(config-router)#router-id 4.4.4.4RTD(config-router)#network 4.4.4.4 0.0.0.0 area 0RTD(config-router)#network 192.168.1.0 0.0.0.255 area 0RTD(config-router)#network 192.168.2.0 0.0.0.255 area 0(2)BGP基本配置/RTA配置RTA(config)#router bgp 100RTA(config-router)#bgp router-id 1.1.1.1RTA(config-router)#network 10.10.10.10 mask 255.255.255.255RTA(config-router)#neighbor 100.1.1.2 remote-as 200RTA(config-router)#neighbor 100.1.2.2 remote-as 200/RTB配置RTB(config)#router bgp 200RTB(config-router)#bgp router-id 2.2.2.2RTB(config-router)#neighbor 4.4.4.4 remote-as 200RTB(config-router)#neighbor 4.4.4.4 update-source Loopback0RTB(config-router)#neighbor 100.1.1.1 remote-as 100RTB(config-router)#address-family ipv4RTB(config-router-af)#neighbor 4.4.4.4 activateRTB(config-router-af)#neighbor 100.1.1.1 activate/RTC配置RTC(config)#router bgp 200RTC(config-router)#bgp router-id 3.3.3.3RTC(config-router)#neighbor 4.4.4.4 remote-as 200RTC(config-router)#neighbor 4.4.4.4 update-source Loopback0RTC(config-router)#neighbor 100.1.2.1 remote-as 100RTC(config-router)#address-family ipv4RTC(config-router-af)#neighbor 4.4.4.4 activateRTC(config-router-af)#neighbor 100.1.2.1 activate/RTD配置RTD(config)#router bgp 200RTD(config-router)#bgp router-id 4.4.4.4RTD(config-router)#network 40.40.40.40 mask 255.255.255.255RTD(config-router)#neighbor 2.2.2.2 remote-as 200RTD(config-router)#neighbor 2.2.2.2 update-source Loopback0RTD(config-router)#neighbor 3.3.3.3 remote-as 200RTD(config-router)#neighbor 3.3.3.3 update-source Loopback0查看RTD BGP路由信息RTD#show ip bgpBGP table version is 2, local router ID is 4.4.4.4Status codes: s suppressed, d damped, h history, * valid, best, i - internal,r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,x best-external, a additional-path, c RIB-compressed,Origin codes: i - IGP, e - EGP, ? - incompleteRPKI validation codes: V valid, I invalid, N Not foundNetworkNext HopMetricLocPrfWeightPath* i 10.10.10.10/32100.1.1.10 1000100 i* i 100.1.2.10 1000100 i* 40.40.40.40/32 0.0.0.00 32768i从上述现象发现，RTD学习的10.10.10.10/32路由的下一跳地址为RTA，针对RTD而言不可达，所以该路由非有最优(3)配置NEXT_HOP属性/RTB配置RTB(config-router-af)#neighbor 4.4.4.4 next-hop-self/RTC配置RTC(config-router-af)#neighbor 4.4.4.4 next-hop-self查看RTD BGP路由信息RTD#show ip bgpBGP table version is 4, local router ID is 4.4.4.4Status codes: s suppressed, d damped, h history, * valid, best, i - internal,r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,x best-external, a additional-path, c RIB-compressed,Origin codes: i - IGP, e - EGP, ? - incompleteRPKI validation codes: V valid, I invalid, N Not foundNetworkNext HopMetricLocPrfWeightPath* i10.10.10.10/323.3.3.301000100 i*i2.2.2.201000100 i* 40.40.40.40/320.0.0.0032768i(4)配置LOCAL_PREFERENCE属性/RTC配置RTC(config-router-af)#bgp default local-preference 200查看RTD BGP路由信息RTD#show ip bgpBGP table version is 4, local router ID is 4.4.4.4Status codes: s suppressed, d damped, h history, * valid, best, i - internal,r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,x best-external, a additional-path, c RIB-compressed,Origin codes: i - IGP, e - EGP, ? - incompleteRPKI validation codes: V valid, I invalid, N Not foundNetworkNext HopMetricLocPrfWeightPath* i10.10.10.10/322.2.2.20 1000100 i*i3.3.3.30 2000100 i* 40.40.40.40/320.0.0.00 32768i从上述现象发现，RTD优选从RTC接收10.10.10.10/32路由RTD#traceroute10.10.10.10 source 40.40.40.40Type escape sequence to abort.Tracing the route to 10.10.10.10VRF info: (vrf in name/id, vrf out name/id)1 192.168.2.1 1 msec 1 msec 1 msec2 100.1.2.1 1 msec 1 msec *从上述现象发现，RTD的40.40.40.40/32网段访问10.10.10.10/32网段的流量路径走RTD-RTC-RTA南京建策科技股份有限公司于2004年成立，是IT教育培训中心。建策科技建立了完整的建策职业教育体系，致力于搭建为高校、学生、企业提供一站式解决方案的综合性