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BGP选路综合实验

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2023-12-25

BGP选路综合实验

实验要求：

1.使用PreVal策略，确保R1通过R3到达192.168.10.0/24

2.使用AS_Path策略，确保R1通过R3到达192.168.11.0/24

3.配置MED策略，确保R1通过R3到达192.168.12.0/24

4.使用Local Preference策略，确保R4通过R2到达192.168.1.0/24

5.使用Local Preference策略，确保R4通过R3到达192.168.2.0/24

6.配置负载均衡，确保R4通过R2和R3到达192.168.3.0/24

7.使用As策略，AS 500 不接受任何始发于As 123 的路由

8.使用自定义Community策略，确保192.168.3.0/24路由不会被发布到As 500

IBGP使用环回接口建邻，EBGP使用物理接口建邻

修改As 123 中的用户网段为Broadcast，方便后续在BGP中宣告

BGP宣告路由时，仅宣告24网段的用户路由

实验配置：

R1：
#
interface GigabitEthernet0/0/0
 ip address 10.0.12.1 255.255.255.0 
#
interface GigabitEthernet0/0/1
 ip address 10.0.13.1 255.255.255.0 
#
interface LoopBack0
 ip address 1.1.1.1 255.255.255.255 
#
bgp 1
 peer 10.0.12.2 as-number 234 
 peer 10.0.13.3 as-number 234 
 #
 ipv4-family unicast
  undo synchronization
  import-route static
  peer 10.0.12.2 enable
  peer 10.0.12.2 route-policy as_path import  ----->从R2引入的路由应用as_path策略
  peer 10.0.12.2 route-policy comm export ----->向R2发布的路由应用comm策略
  peer 10.0.12.2 advertise-community ----->向R2发布团体属性
  peer 10.0.13.3 enable
  peer 10.0.13.3 route-policy preval import ----->从R3引入的路由应用preval策略
  peer 10.0.13.3 route-policy comm export ----->向R3发布的路由应用comm策略
  peer 10.0.13.3 advertise-community ----->向R3发布团体属性

#
route-policy preval permit node 10 
 if-match ip-prefix 1 ----->匹配前缀列表1
 apply preferred-value 10 ----->修改pre-value值为10
#
route-policy preval permit node 20 ----->只匹配需要的路由，并修改其路由信息，其他的路由信息不做改变，正常放通
#
route-policy as_path permit node 10 
 if-match ip-prefix 2 ----->匹配前缀列表2
 apply as-path 234 additive ----->多添加as_path属性给该路由信息
#
route-policy as_path permit node 20 ----->只匹配需要的路由，并修改其路由信息，其他的路由信息不做改变，正常放通
#
route-policy comm permit node 10 
 if-match ip-prefix 3 ----->匹配前缀列表3
 apply community 1:1 no-export ----->应用团体属性为1:1，且是no-export属性
#
route-policy comm permit node 20 ----->只匹配需要的路由，并修改其路由信息，其他的路由信息不做改变，正常放通
#
ip ip-prefix 1 index 10 permit 192.168.10.0 24
ip ip-prefix 2 index 10 permit 192.168.11.0 24
ip ip-prefix 3 index 10 permit 192.168.3.0 24
#
ip route-static 192.168.1.0 255.255.255.0 NULL0
ip route-static 192.168.2.0 255.255.255.0 NULL0
ip route-static 192.168.3.0 255.255.255.0 NULL0
R2:
#
interface GigabitEthernet0/0/0
 ip address 10.0.12.2 255.255.255.0 
#
interface GigabitEthernet0/0/1
 ip address 10.0.24.2 255.255.255.0 
#
interface LoopBack0
 ip address 2.2.2.2 255.255.255.255 
#
bgp 234
 peer 4.4.4.4 as-number 234 
 peer 4.4.4.4 connect-interface LoopBack0
 peer 10.0.12.1 as-number 1 
 #
 ipv4-family unicast
  undo synchronization
  network 172.16.112.0 255.255.255.0 
  peer 4.4.4.4 enable
  peer 4.4.4.4 route-policy local_pre export ----->向R4发布的路由应用local_pre策略
  peer 4.4.4.4 next-hop-local 
  peer 4.4.4.4 advertise-community 
  peer 10.0.12.1 enable
  peer 10.0.12.1 route-policy med export ----->向R1发布的路由应用med策略

#
ospf 1 router-id 2.2.2.2 
 area 0.0.0.0 
  network 2.2.2.2 0.0.0.0 
  network 10.0.24.2 0.0.0.0 
#
route-policy med permit node 10 
 if-match ip-prefix 1 
 apply cost 10 ---->修改med属性值为10 （越小越优）
#
route-policy med permit node 20 
#
route-policy local_pre permit node 10 
 if-match ip-prefix 2 
 apply local-preference 200 ---->修改本地优先级值为200（越大越优）
#
route-policy local_pre permit node 20 
 if-match ip-prefix 3 
 apply local-preference 100 ---->修改本地优先级值为100（越大越优）
#
route-policy local_pre permit node 30 
#
ip ip-prefix 1 index 10 permit 192.168.12.0 24
ip ip-prefix 2 index 10 permit 192.168.1.0 24
ip ip-prefix 3 index 10 permit 192.168.2.0 24
#
ip route-static 172.16.112.0 255.255.255.0 NULL0
R3:
#
interface GigabitEthernet0/0/0
 ip address 10.0.13.3 255.255.255.0 
#
interface GigabitEthernet0/0/1
 ip address 10.0.34.3 255.255.255.0 
#
interface GigabitEthernet0/0/2
#
interface NULL0
#
interface LoopBack0
 ip address 3.3.3.3 255.255.255.255 
#
bgp 234
 peer 4.4.4.4 as-number 234 
 peer 4.4.4.4 connect-interface LoopBack0
 peer 10.0.13.1 as-number 1 
 #
 ipv4-family unicast
  undo synchronization
  network 172.16.113.0 255.255.255.0 
  peer 4.4.4.4 enable
  peer 4.4.4.4 route-policy local_pre export ----->向R4发布的路由应用local_pre策略
  peer 4.4.4.4 next-hop-local 
  peer 4.4.4.4 advertise-community 
  peer 10.0.13.1 enable
  peer 10.0.13.1 route-policy med export ----->向R1发布的路由应用med策略
#
ospf 1 router-id 3.3.3.3 
 area 0.0.0.0 
  network 3.3.3.3 0.0.0.0 
  network 10.0.34.3 0.0.0.0 
#
route-policy med permit node 10 
 if-match ip-prefix 1 
 apply cost 5 ---->修改med属性值为10 （越小越优）
#
route-policy med permit node 20 
#
route-policy local_pre permit node 10 
 if-match ip-prefix 2 
 apply local-preference 100 ---->修改本地优先级值为100（越大越优）
#
route-policy local_pre permit node 20 
 if-match ip-prefix 3 
 apply local-preference 200 ---->修改本地优先级值为200（越大越优）
#
route-policy local_pre permit node 30 
#
route-policy test permit node 10 
#
ip ip-prefix 1 index 10 permit 192.168.12.0 24
ip ip-prefix 2 index 10 permit 192.168.1.0 24
ip ip-prefix 3 index 10 permit 192.168.2.0 24
#
ip route-static 172.16.113.0 255.255.255.0 NULL0
R4:
#
interface GigabitEthernet0/0/0
 ip address 10.0.24.4 255.255.255.0 
#
interface GigabitEthernet0/0/1
 ip address 10.0.34.4 255.255.255.0 
#
interface GigabitEthernet0/0/2
 ip address 10.0.45.4 255.255.255.0 
#
interface LoopBack0
 ip address 4.4.4.4 255.255.255.255 
#
bgp 234
 peer 2.2.2.2 as-number 234 
 peer 2.2.2.2 connect-interface LoopBack0
 peer 3.3.3.3 as-number 234 
 peer 3.3.3.3 connect-interface LoopBack0
 peer 10.0.45.5 as-number 5 
 #
 ipv4-family unicast
  undo synchronization
  maximum load-balancing 2 ----->在R4的bgp中应用负载均衡，将最大负载均衡数变成2（默认是1，即默认是bgp不允许负载均衡路由出现）
  peer 2.2.2.2 enable
  peer 2.2.2.2 next-hop-local 
  peer 3.3.3.3 enable
  peer 3.3.3.3 next-hop-local 
  peer 10.0.45.5 enable
#
ospf 1 router-id 4.4.4.4 
 area 0.0.0.0 
  network 4.4.4.4 0.0.0.0 
  network 10.0.24.4 0.0.0.0 
  network 10.0.34.4 0.0.0.0 
R5:
interface GigabitEthernet0/0/0
 ip address 10.0.45.5 255.255.255.0 
#
interface LoopBack0
 ip address 5.5.5.5 255.255.255.255 
#
bgp 5
 peer 10.0.45.4 as-number 234 
 #
 ipv4-family unicast
  undo synchronization
  import-route static
  peer 10.0.45.4 enable
  peer 10.0.45.4 as-path-filter 1 import 
#
ip as-path-filter 1 deny _234$ ----->采用as_path过滤工具，_234$代表匹配路由条目最右边的数字（即起源as234的路由），并deny拒绝掉该路由
ip as-path-filter 1 permit .* ----->在该AS路径过滤工具中，允许放通所有流量（as过滤默认拒绝所有流量）
注意：
拒绝的语句一定要写在允许的前面，代表只拒绝起源于as234的路由，但是放通其他所有的路由
#
ip route-static 192.168.10.0 255.255.255.0 NULL0
ip route-static 192.168.11.0 255.255.255.0 NULL0
ip route-static 192.168.12.0 255.255.255.0 NULL0

实验现象：


#network 18