BGP属性及配置

Posted 2020-12-19 xuhao0705

一、BGP属性分类

公有必遵	Origin（起源属性）	IGP（i）、EGP（e）、Incomplete（?）
	AS-PATH（路径属性）	越短越优(EBGP、IBGP)
	Next-Hop（下一跳属性）	/
公认任意	Local Pref（本地优先级属性）	越大越优(IBGP)
可选过渡	Community（社区属性）	/
可选非过渡	MED属性	MED值越小越优(EBGP、IBGP)

 

 

 

二、BGP选路规则

1、若去往目的网络的路由下一跳不可达，则可以忽略此路由

2、Preferred-Value优先级以数值高的路由优先

3、Local-Preference优先级以数值高的路由优先（默认100）

4、聚合路由优先级高于非聚合路由

5、本地手动聚合路由的优先级高于本地自动聚合的路由

6、本地通过Network命令引入的路由的优先级高于本地通过Import-route命令引入的路由

7、AS路径长度最短（最少个数）的路径优先级高

8、比较Origin属性，IGP优先级高于EGP，EGP优先级高于Incomplete

9、选择MED优先级较小的路由

10、EBGP路由优先级高于IBGP路由

11、BGP优先选择到BGP下一跳的IGP度量低的路经

当以上全部相同，则为等价路由，可以负载分担(注：AS-PATH必须一致)，当负载分担时，以下3条原则无线

12、比较Cluster-List长度，短者优先

13、比较Originator ID(如果没有Originator ID，则用Router ID比较)选择数值较小的路径

14、比较对等体的IP地址，选择IP地址数值最小的路径

 

 

三、BGP属性配置

 

要求：R1环回到R5 环回从R2走

      R5环回到R1 环回从R3走

R1配置信息：

<Huawei>undo terminal monitor

<Huawei>system-view

[Huawei]user-interface console 0

[Huawei-ui-console0]idle-timeout 0 0

[Huawei-ui-console0]sysname R1

[R1]int g0/0/0

[R1-GigabitEthernet0/0/0]ip add 12.1.1.1 24

[R1-GigabitEthernet0/0/0]undo shutdown

[R1-GigabitEthernet0/0/0]int g0/0/1

[R1-GigabitEthernet0/0/1]ip add 13.1.1.1 24

[R1-GigabitEthernet0/0/1]undo shutdown

[R1-GigabitEthernet0/0/1]int loop 0

[R1-LoopBack0]ip add 1.1.1.1 32

[R1-LoopBack0]quit

[R1]ip route-static 2.2.2.2 32 12.1.1.2

[R1]ip route-static 3.3.3.3 32 13.1.1.2

[R1]bgp 300

[R1-bgp]router-id 1.1.1.1

[R1-bgp]peer 2.2.2.2 as-number 200

[R1-bgp]peer 2.2.2.2 connect-interface loop 0

[R1-bgp]peer 2.2.2.2 ebgp-max-hop 255

[R1-bgp]peer 3.3.3.3 as-number 200

[R1-bgp]peer 3.3.3.3 connect-interface loop 0

[R1-bgp]peer 3.3.3.3 ebgp-max-hop 255

[R1-bgp]network 1.1.1.1 32

[R1-bgp]network 12.1.1.0 24

[R1-bgp]network 13.1.1.0 24

R2配置信息：

<Huawei>undo terminal monitor

<Huawei>system-view

[Huawei]user-interface console 0

[Huawei-ui-console0]idle-timeout 0 0

[Huawei-ui-console0]sysname R2

[R2]int g0/0/0

[R2-GigabitEthernet0/0/0]ip add 12.1.1.2 24

[R2-GigabitEthernet0/0/0]undo shutdown

[R2-GigabitEthernet0/0/0]int g0/0/1

[R2-GigabitEthernet0/0/1]ip add 23.1.1.2 24

[R2-GigabitEthernet0/0/1]undo shutdown

[R2-GigabitEthernet0/0/1]int loop 0

[R2-LoopBack0]ip add 2.2.2.2 32

[R2-LoopBack0]quit

[R2]ospf 1 router-id 2.2.2.2

[R2-ospf-1]area 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 23.1.1.0 0.0.0.255

[R2-ospf-1-area-0.0.0.0]quit

[R2-ospf-1]quit

[R2]ip route-static 1.1.1.1 32 12.1.1.1

[R2]bgp 200

[R2-bgp]router-id 2.2.2.2

[R2-bgp]peer 1.1.1.1 as-number 100

[R2-bgp]peer 1.1.1.1 connect-interface loop 0

[R2-bgp]peer 1.1.1.1 ebgp-max-hop 255

[R2-bgp]peer 3.3.3.3 as-number 200

[R2-bgp]peer 3.3.3.3 connect-interface loop 0

[R2-bgp]peer 3.3.3.3 next-hop-local

[R2-bgp]peer 4.4.4.4 as-number 200

[R2-bgp]peer 4.4.4.4 connect-interface loop 0

[R2-bgp]peer 4.4.4.4 next-hop-local

[R2-bgp]network 1.1.1.1 32

[R2-bgp]network 2.2.2.2 32

[R2-bgp]network 3.3.3.3 32

[R2-bgp]network 4.4.4.4 32

[R2-bgp]network 12.1.1.0 24

[R2-bgp]network 23.1.1.0 24

[R2-bgp]quit

R3配置信息：

<Huawei>undo terminal monitor

<Huawei>system-view

[Huawei]user-interface console 0

[Huawei-ui-console0]idle-timeout 0 0

[Huawei-ui-console0]sysname R3

[R3]int g0/0/0

[R3-GigabitEthernet0/0/0]ip add 13.1.1.3 24

[R3-GigabitEthernet0/0/0]undo shutdown

[R3-GigabitEthernet0/0/0]int g0/0/1

[R3-GigabitEthernet0/0/1]ip add 34.1.1.3 24

[R3-GigabitEthernet0/0/1]undo shutdown

[R3-GigabitEthernet0/0/1]int loop 0

[R3-LoopBack0]ip add 3.3.3.3 32

[R3-LoopBack0]quit

[R3]ospf 1 router-id 3.3.3.3

[R3-ospf-1]area 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 34.1.1.0 0.0.0.255

[R3-ospf-1-area-0.0.0.0]quit

[R3-ospf-1]quit

[R3]ip route-static 1.1.1.1 32 13.1.1.1

[R3]bgp 200

[R3-bgp]peer 1.1.1.1 as-number 100

[R3-bgp]peer 1.1.1.1 connect-interface loop 0

[R3-bgp]peer 1.1.1.1 ebgp-max-hop 255

[R3-bgp]peer 2.2.2.2 as-number 200

[R3-bgp]peer 2.2.2.2 connect-interface loop 0

[R3-bgp]peer 2.2.2.2 next-hop-local

[R3-bgp]peer 4.4.4.4 as-number 200

[R3-bgp]peer 4.4.4.4 connect-interface loop 0

[R3-bgp]peer 4.4.4.4 next-hop-local

[R3-bgp]network 1.1.1.1 32

[R3-bgp]network 2.2.2.2 32

[R3-bgp]network 3.3.3.3 32

[R3-bgp]network 4.4.4.4 32

[R3-bgp]network 13.1.1.0 24

[R3-bgp]network 34.1.1.0 24

[R3]acl 2000

[R3-acl-basic-2000]rule permit source 5.5.5.5 0.0.0.0

[R3-acl-basic-2000]quit

[R3]route-policy as permit node 10

[R3-route-policy]if-match acl 2000

[R3-route-policy]apply as-path 222 333 444 additive

[R3-route-policy]quit

[R3]route-policy as permit node  20

[R3-route-policy]quit

[R3]bgp 200

[R3-bgp]peer 1.1.1.1 route-policy as export

[R3-bgp]quit

[R3]quit

<R3>reset bgp all

<R3>system-view

[R3]acl 2001

[R3-acl-basic-2001]rule permit source 1.1.1.1 0.0.0.0

[R3-acl-basic-2001]quit

[R3]route-policy local permit node 10

[R3-route-policy]if-match acl 2001

[R3-route-policy]apply local-preference 200

[R3-route-policy]quit

[R3]route-policy local permit node 20

[R3-route-policy]quit

[R3]bgp 200

[R3-bgp]peer 4.4.4.4 route-policy local export

[R3-bgp]quit

[R3]quit

<R3>reset bgp all

R4配置信息：

<Huawei>undo terminal monitor

<Huawei>system-view

[Huawei]user-interface console 0

[Huawei-ui-console0]idle-timeout 0 0

[Huawei-ui-console0]sysname R4

[R4]int g0/0/0

[R4-GigabitEthernet0/0/0]ip add 23.1.1.4 24

[R4-GigabitEthernet0/0/0]undo shutdown

[R4-GigabitEthernet0/0/0]int g0/0/1

[R4-GigabitEthernet0/0/1]ip add 34.1.1.4 24

[R4-GigabitEthernet0/0/1]undo shutdown

[R4-GigabitEthernet0/0/1]int g0/0/2

[R4-GigabitEthernet0/0/2]ip add 45.1.1.4 24

[R4-GigabitEthernet0/0/2]undo shutdown

[R4-GigabitEthernet0/0/1]int loop 0

[R4-LoopBack0]ip add 4.4.4.4 32

[R4-LoopBack0]quit

[R4]ospf 1 router-id 4.4.4.4

[R4-ospf-1]area 0

[R4-ospf-1-area-0.0.0.0]network 4.4.4.4 0.0.0.0

[R4-ospf-1-area-0.0.0.0]network 23.1.1.0 0.0.0.255

[R4-ospf-1-area-0.0.0.0]network 34.1.1.0 0.0.0.255

[R4-ospf-1-area-0.0.0.0]quit

[R4-ospf-1]quit

[R4]ip route-static 1.1.1.1 32 13.1.1.1

 

[R4]bgp 200

[R4-bgp]router-id 4.4.4.4

[R4-bgp]peer 2.2.2.2 as-number 200

[R4-bgp]peer 2.2.2.2 connect-interface loop 0

[R4-bgp]peer 2.2.2.2 next-hop-local

[R4-bgp]peer 3.3.3.3 as-number 200

[R4-bgp]peer 3.3.3.3 connect-interface loop 0

[R4-bgp]peer 3.3.3.3 next-hop-local

[R4-bgp]peer 5.5.5.5 as-number 300

[R4-bgp]peer 5.5.5.5 connect-interface loop 0

[R4-bgp]peer 5.5.5.5 ebgp-max-hop 255

[R4-bgp]quit

[R4]ip route-static 5.5.5.5 32 45.1.1.5

[R4]bgp 200

[R4-bgp]network 2.2.2.2 32

[R4-bgp]network 3.3.3.3 32

[R4-bgp]network 4.4.4.4 32

[R4-bgp]network 5.5.5.5 32

[R4-bgp]network 34.1.1.0 24

[R4-bgp]network 23.1.1.0 24

[R4-bgp]network 45.1.1.0 24

R5配置信息：

<Huawei>undo terminal monitor

<Huawei>system-view

[Huawei]user-interface console 0

[Huawei-ui-console0]idle-timeout 0 0

[Huawei-ui-console0]sysname R5

[R5]int g0/0/0

[R5-GigabitEthernet0/0/0]ip add 45.1.1.5 24

[R5-GigabitEthernet0/0/0]undo shutdown

[R5-GigabitEthernet0/0/0]int loop 0

[R5-LoopBack0]ip add 5.5.5.5 32

[R5-LoopBack0]quit

[R5]ip route-static 4.4.4.4 32 45.1.1.4

[R5]bgp 300

[R5-bgp]router-id 5.5.5.5

[R5-bgp]peer 4.4.4.4 as-number 200

[R5-bgp]peer 4.4.4.4 connect-interface loop 0

[R5-bgp]peer 4.4.4.4 ebgp-max-hop 255

[R5-bgp]network 5.5.5.5 32

[R5-bgp]network 45.1.1.0 24