華爲AR2220 在AS內Preference_Value對選路的影響（Preference_Value僅影響自己的選路，不能影響其他設備）

一、網絡拓撲

需求：AR1默認選擇路線是AR1 > AR2 > AR4到200.1.1.1，但是鏈路帶寬低。現在希望在AS65008內僅改變AR1的配置，就能實現選擇高帶寬鏈路，路線訪問：AR1 > AR3 > AR4 到200.1.1.1

• 在AR1上做Preference_Value配置，將策略應用在對RTC發佈路由的 import方向
• 缺省情況下，從其它BGP對等體學來的路由的首選Preference_Value值爲0

二、基本配置

1、AR1

1、配置接口
<Huawei>system-view 
[Huawei]sysname AR1	
[AR1]interface  LoopBack 0
[AR1-LoopBack0]ip address  1.1.1.1 32	
[AR1-LoopBack0]quit	
[AR1]interface  GigabitEthernet  0/0/0
[AR1-GigabitEthernet0/0/0]ip address  10.1.12.1 24
[AR1-GigabitEthernet0/0/0]quit
[AR1]interface  GigabitEthernet  0/0/1
[AR1-GigabitEthernet0/0/1]ip address  10.1.13.1 24
[AR1-GigabitEthernet0/0/1]quit

2、配置OSPF
[AR1]ospf router-id 1.1.1.1
[AR1-ospf-1]area 0
[AR1-ospf-1-area-0.0.0.0]network  10.1.12.0 0.0.0.255
[AR1-ospf-1-area-0.0.0.0]network  10.1.13.0 0.0.0.255
[AR1-ospf-1-area-0.0.0.0]quit
[AR1-ospf-1]import-route direct
[AR1-ospf-1]quit

3、配置IBGP
[AR1]bgp 65008
[AR1-bgp]peer 10.1.12.2 as-number 65008
[AR1-bgp]peer 10.1.13.3 as-number 65008
[AR1-bgp]import-route ospf 1
[AR1-bgp]quit

2、AR2

1、配置接口
<Huawei>system-view
[Huawei]sysname AR2
[AR2]interface  LoopBack  0
[AR2-LoopBack0]ip address  2.2.2.2 32
[AR2-LoopBack0]quit
[AR2]interface  GigabitEthernet  0/0/0
[AR2-GigabitEthernet0/0/0]ip address  10.1.12.2 24	
[AR2-GigabitEthernet0/0/0]quit
[AR2]interface  GigabitEthernet  0/0/2
[AR2-GigabitEthernet0/0/2]ip address  10.1.24.2 24	
[AR2-GigabitEthernet0/0/2]quit

2、配置OSPF
[AR2]ospf router-id 2.2.2.2
[AR2-ospf-1]area 0
[AR2-ospf-1-area-0.0.0.0]network  10.1.12.0 0.0.0.255
[AR2-ospf-1-area-0.0.0.0]quit
[AR2-ospf-1]import-route direct
[AR2-ospf-1]quit

3、配置BGP
[AR2]bgp 65008
[AR2-bgp]peer 10.1.12.1 as-number 65008
[AR2-bgp]peer 10.1.24.4 as-number 65009
[AR2-bgp]import-route ospf 1
[AR2-bgp]quit

3、AR3

1、配置接口
<Huawei>system-view	
[Huawei]sysname AR3	
[AR3]interface  LoopBack  0
[AR3-LoopBack0]ip address  3.3.3.3 32
[AR3-LoopBack0]quit
[AR3]interface  GigabitEthernet  0/0/1
[AR3-GigabitEthernet0/0/1]ip address  10.1.13.3 24
[AR3-GigabitEthernet0/0/1]quit	
[AR3]interface  GigabitEthernet  0/0/0
[AR3-GigabitEthernet0/0/0]ip address 10.1.34.3 24
[AR3-GigabitEthernet0/0/0]quit

2、配置OSPF
[AR3]ospf router-id 3.3.3.3
[AR3-ospf-1]area 0
[AR3-ospf-1-area-0.0.0.0]network 10.1.13.0 0.0.0.255
[AR3-ospf-1-area-0.0.0.0]quit
[AR3-ospf-1]import-route direct 
[AR3-ospf-1]quit

3、配置BGP
[AR3]bgp 65008
[AR3-bgp]peer 10.1.13.1 as-number 65008
[AR3-bgp]peer 10.1.34.4 as-number 65009
[AR3-bgp]import-route  ospf  1
[AR3-bgp]quit

4、AR4

1、配置接口
<Huawei>system-view
[Huawei]sysname AR4
[AR4]interface  LoopBack  0
[AR4-LoopBack0]ip address  4.4.4.4 32	
[AR4-LoopBack0]quit
[AR4]interface  LoopBack  1
[AR4-LoopBack1]ip address  200.1.1.1 24
[AR4-LoopBack1]quit
[AR4]interface  LoopBack  2
[AR4-LoopBack2]ip address  200.1.2.1 24
[AR4-LoopBack2]quit
[AR4]interface  GigabitEthernet  0/0/2
[AR4-GigabitEthernet0/0/2]ip address  10.1.24.4 24
[AR4-GigabitEthernet0/0/2]quit
[AR4]interface  GigabitEthernet  0/0/0
[AR4-GigabitEthernet0/0/0]ip address  10.1.34.4 24
[AR4-GigabitEthernet0/0/0]quit

2、配置BGP
[AR4]bgp 65009
[AR4-bgp]peer 10.1.24.2 as-number 65008
[AR4-bgp]peer 10.1.34.3 as-number 65008
[AR4-bgp]import-route direct 
[AR4-bgp]quit

5、跟蹤查看默認線路

三、全部目的地址改變線路

1、AR1修改Preference_Value配置

[AR1]bgp  65008
[AR1-bgp]ipv4-family unicast
[AR1-bgp-af-ipv4]peer 10.1.13.3 preferred-value 100
[AR1-bgp-af-ipv4]return

2、查看BGP路由表的PrefVal值

3、跟蹤路由查看

四、部分目的地址改變線路

1、修改Preference_Value，將策略應用在對RTC發佈路由的 import方向

[AR1]bgp 65008	
[AR1-bgp]ipv4-family unicast
[AR1-bgp-af-ipv4]undo peer 10.1.13.3 preferred-value
[AR1-bgp-af-ipv4]peer 10.1.13.3 route-policy pref-val import
[AR1-bgp-af-ipv4]return

2、定義路由策略

[AR1]route-policy pref-val permit node 10
[AR1-route-policy]if-match ip-prefix pref-val
[AR1-route-policy]apply preferred-value 100
[AR1-route-policy]quit

3、創建IPv4地址前綴列表

[AR1]ip ip-prefix pref-val index 10 permit 200.1.1.0 24

4、查看BGP路由表

5、跟蹤路由查看