首先配置IP地址
然后配置IGP使路由器配通
[r1]ospf 1 router-id 1.1.1.1
[r1-ospf-1]a 0
[r1-ospf-1-area-0.0.0.0]network 1.1.1.1 0.0.0.0
[r1-ospf-1-area-0.0.0.0]network 192.168.100.0 0.0.0.255
[r1-ospf-1-area-0.0.0.0]network 12.0.0.1 0.0.0.0
[r1-ospf-1-area-0.0.0.0]network 13.0.0.1 0.0.0.0
[r1-ospf-1-area-0.0.0.0]network 15.0.0.1 0.0.0.0
[r2]ospf 1 router-id 2.2.2.2
[r2-ospf-1]a 0
[r2-ospf-1-area-0.0.0.0]network 24.0.0.2 0.0.0.0
[r2-ospf-1-area-0.0.0.0]network 12.0.0.2 0.0.0.0
[r2-ospf-1-area-0.0.0.0]network 2.2.2.2 0.0.0.0
[r2-ospf-1-area-0.0.0.0]network 192.168.20.0 0.0.0.255
[r3]ospf 1 router-id 3.3.3.3
[r3-ospf-1]a 0
[r3-ospf-1-area-0.0.0.0]network 13.0.0.3 0.0.0.0
[r3-ospf-1-area-0.0.0.0]network 34.0.0.3 0.0.0.0
[r3-ospf-1-area-0.0.0.0]network 3.3.3.3 0.0.0.0
[r3-ospf-1-area-0.0.0.0]network 192.168.30.0 0.0.0.255
然后运行BGP
[r4]bgp 400
[r4-bgp]router-id 4.4.4.4
[r4-bgp]peer 24.0.0.2 as-number 123
[r4-bgp]peer 34.0.0.3 as-number 123
[r1]bgp 123
[r1-bgp]router-id 1.1.1.1
[r1-bgp]peer 12.0.0.2 as-number 123
[r1-bgp]peer 12.0.0.2 connect-interface l 0
[r1-bgp]peer 13.0.0.3 as-number 123
[r1-bgp]peer 13.0.0.3 connect-interface l 0
[r1-bgp]peer 15.0.0.5 as-number 500
[r1-bgp]peer 15.0.0.5 connect-interface l 0
[r2]bgp 123
[r2-bgp]router-id 2.2.2.2
[r2-bgp]peer 12.0.0.1 as-number 123
[r2-bgp]peer 12.0.0.1 connect-interface l 0
[r2-bgp]peer 24.0.0.4 as-number 400
[r2-bgp]peer 24.0.0.4 connect-interface l 0
[r3]bgp 123
[r3-bgp]router-id 3.3.3.3
[r3-bgp]peer 13.0.0.1 as-number 123
[r3-bgp]peer 13.0.0.1 connect-interface l 0
[r3-bgp]peer 34.0.0.4 as-number 400
[r3-bgp]peer 34.0.0.4 connect-interface l 0
[r5]bgp 500
[r5-bgp]router-id 5.5.5.5
[r5-bgp]peer 15.0.0.1 as-number 123
建邻完后宣告IP
[r4]bgp 400
[r4-bgp]network 192.168.1.0 24
[r4-bgp]network 192.168.2.0 24
[r4-bgp]network 192.168.3.0 24
[r1]bgp 123
[r1-bgp]network 192.168.100.0 24
[r2]bgp 123
[r2-bgp]network 192.168.20.0 24
[r3]bgp 123
[r3-bgp]network 192.168.30.0 24
[r5]bgp 500
[r5-bgp]network 192.168.10.0 24
[r5-bgp]network 192.168.11.0 24
[r5-bgp]network 192.168.12.0 24
使用preval策略，确保R4通过R2到达192.168.10.0/24
[r4]ip ip-prefix PV permit 192.168.10.0 24
[r4]route-policy PV permit node 10
Info: New Sequence of this List.
[r4-route-policy]if-match ip-prefix PV
[r4-route-policy]apply preferred-value 100
[r4-route-policy]q
[r4]route-policy PV permit node 20
Info: New Sequence of this List.
[r4-route-policy]q
[r4]bgp 400
[r4-bgp]peer 24.0.0.2 route-policy PV import
使用AS_PATH策略，确保R4通过R3到达192.168.11.0/24
[r4]route-policy AS permit node 11
Info: New Sequence of this List.
[r4-route-policy]if-match ip-prefix AS
[r4-route-policy]apply as-path 400 123 overwrite
[r4-route-policy]q
[r4]route-policy AS permit node 21
Info: New Sequence of this List.
[r4-route-policy]q
[r4]bgp 400
[r4-bgp]peer 34.0.0.3 route-policy AS export
使用MED策略，确保R4通过R3到达192.168.12.0/24
[r4]bgp 400
[r4-bgp]default med 10
[r3]ip ip-prefix MED permit 192.168.12.0 24
[r3]route-policy MED permit node 10
Info: New Sequence of this List.
[r3-route-policy]if-match ip-prefix MED
[r3-route-policy]apply cost 20
[r3-route-policy]q
[r3]route-policy MED permit node 20
Info: New Sequence of this List.
[r3-route-policy]q
[r3]bgp 123
[r3-bgp]peer 34.0.0.4 route-policy MED export
使用Local Preference策略，确保R1通过R2到达192.168.1.0
[r1]ip ip-prefix LP permit 192.168.1.0 24
[r1]route-policy LP permit node 10
Info: New Sequence of this List.
[r1-route-policy]if-match ip-prefix LP
[r1-route-policy]apply local-preference 200
[r1-route-policy]q
[r1]route-policy LP permit node 20
Info: New Sequence of this List.
[r1-route-policy]bgp 123
[r1-bgp]pe
[r1-bgp]peer 12.0.0.2 route-policy LP import
使用Local Preference策略，确保R1通过R3到达192.168.2.0
[r1]ip ip-prefix LP2 permit 192.168.2.0 24
[r1]route-policy LP2 permit node 11
Info: New Sequence of this List.
[r1-route-policy]if-match ip-prefix LP2
[r1-route-policy]apply local-preference 200
[r1-route-policy]q
[r1]route-policy LP2 permit node 21
Info: New Sequence of this List.
[r1-route-policy]q
[r1]bgp 123
[r1-bgp]peer 13.0.0.3 route-policy LP2 import
配置负载均衡，确保R1通过R2和R3到达192.168.3.0
[r1]bgp 123
[r1-bgp]maximum load-balancing 2
[r1-bgp]load-balancing as-path-ignore
使用AS策略，AS 500不接受任何始发于AS 123的路由
[r1]ip as-path-filter 1 deny _123$
[r1]ip as-path-filter 1 permit .*
[r1]bgp 123
[r1-bgp]peer 15.0.0.5 as-path-filter 1 export
使用自定义community策略，确保192.168.3.0路由不会被发布到AS 500
不太会