實驗BGP鄰居建立與路由發(fā)布詳細(xì)分析

1、實驗25 BGP鄰居建立與路由發(fā)布一、組網(wǎng)拓?fù)鋱D：2、 實驗需求：3、 部分配置命令：IGP部分配置：RT1:router bgp 10 no synchronization bgp log-neighbor-changes neighbor 10.10.0.2 remote-as 10 neighbor 10.10.0.2 update-source Loopback03.2 remote-as 30 no auto-summary!RT2:router ospf 1 log-adjacency-changes redistribute connected metric 1000 metri

2、c-type 1 subnets passive-interface default no passive-interface Serial0/1 no passive-interface FastEthernet1/0 network 10.10.0.2 0.0.0.0 area 0 network 10.10.1.0 0.0.0.255 area 0 default-information originate always metric 2000 metric-type 1!RT5:router ospf 1 log-adjacency-changes passive-interface

3、default no passive-interface Serial0/0 no passive-interface FastEthernet1/0 network 10.10.0.5 0.0.0.0 area 0 network 10.10.1.0 0.0.0.255 area 0 network 10.10.5.0 0.0.0.255 area 0!RT6:router ospf 1 log-adjacency-changes passive-interface default no passive-interface Serial0/0 no passive-interface Fas

4、tEthernet1/0 network 10.10.0.6 0.0.0.0 area 0 network 10.10.1.0 0.0.0.255 area 0 network 10.10.6.0 0.0.0.255 area 0!BGP部分配置：RT1:router bgp 10 no synchronization bgp log-neighbor-changes network 10.10.0.0 mas neighbor 10.10.0.2 remote-as 10 neighbor 10.10.0.2 update-source Loopback0 neighbor 10.10.13

5、.2 remote-as 30 no auto-summary!RT2:router bgp 10 no synchronization bgp log-neighbor-changes neighbor 10.10.0.1 remote-as 10 neighbor 10.10.0.1 update-source Loopback0 neighbor 10.20.24.2 remote-as 40 no auto-summary!RT3:router bgp 30 no synchronization bgp log-neighbor-changes neighbor 10.10.13.1

6、remote-as 10 neighbor 10.30.34.2 remote-as 40 no auto-summary!RT4:router bgp 40 no synchronization bgp log-neighbor-changes neighbor 10.20.24.1 remote-as 10 neighbor 10.30.34.1 remote-as 30 no auto-summary!BGP(路由發(fā)布:靜態(tài)注入）：RT1:ip route 10.10.0.0 255.255.0.0 Null0router bgp 10RT2:router bgp 10ip route

7、10.10.0.0 255.255.0.0 Null0RT3:router bgp 30ip route 10.30.0.0 255.255.0.0 Null0!RT4:router bgp 40ip route 10.40.0.0 255.255.0.0 Null0!BGP(路由發(fā)布:動態(tài)注入）：純動態(tài)注入：RT1:router bgp 10 redistribute ospf 1 match internal external 1 external 2!RT2:router bgp 10 redistribute ospf 1 match internal external 1 exter

8、nal 2!半動態(tài)注入：RT1:router bgp 10RT2:router bgp 103、 實驗調(diào)試：1、RT1:鄰居建立：2、 路由發(fā)布：3、路由表：RT2:1、鄰居建立：2、 路由表：3、 bgp表：RT3:1、 鄰居建立：2、 路由表：RT4:1、 鄰居建立：2、路由表：4、 BGP Next-hop-self調(diào)試：5、 ping測試：由追蹤路由可以知道去往的網(wǎng)段的走RT5-RT1-RT2-RT4因為在AS里面同時運行ospf和bgp協(xié)議，如果走RT5-RT6-RT2-RT4,則開銷計算總和：100+100+2跳，而走上面的那條路，則只要開銷總和：100+2跳，因為在RT1上運行b

9、gp，只看需要幾跳。從pc6 ping pc 5 的結(jié)果：從pc5 ping pc 4以及從pc3 ping pc 4的結(jié)果： 從pc3 ping pc 5的結(jié)果以及從pc4 ping pc 5的結(jié)果：為什么不去RT3而是去了RT2?原因很簡單因為去往RT3的AS-PATH:30 40 i而是去往RT2的AS-PATH:40 i，這就是問題的所在了。出現(xiàn)Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.40.4.1, timeout is 2 seconds:.Success rate is 0 percent

10、 (0/5)問題就在于在RT1和RT2上使用半動態(tài)注入（使用network精確發(fā)布IGP路由至BGP），可以去往的路由，但是沒有回的路由。因為只發(fā)布10.10.5.0 的網(wǎng)段，而此時的源地址是出接口s0/0，沒有通告給BGP的緣故！Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.40.4.1, timeout is 2 seconds:Packet sent with a source address of 10.10.5.1 !Success rate is 100 percent (5/5), round-trip min/avg/max = 60/68/88 ms這樣可以了。5、 實驗總結(jié)： 在本次實驗中，遇到一點點小麻煩，比如忘記在RT1上的s0/0做ip ospf cost 100 ，導(dǎo)致O 10.10.13.0/30 110/200 via 10.10.1.1, 00:43:17, FastEthernet1/0這條路由開銷不正常