华为ensp_BGP_local-prefernce；AS-Path；MeD 实验

约定不等于承诺〃 2021-07-26 14:45 1050阅读 0赞

３种选路：  
１．local——ｐｒｅｆｅｒｎｅｃ  
２．ＡＳ＿ＰＡＨ　  
３．ＭＥＤ　![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center]

R1:
    <Huawei>u t m 
    Info: Current terminal monitor is off.
    <Huawei>sys 
    <Huawei>system-view 
    Enter system view, return user view with Ctrl+Z.
    [Huawei]sys 
    [Huawei]sysname R1
    [R1]us 
    [R1]user-int 
    [R1]user-interface co 
    [R1]user-interface console 0
    [R1-ui-console0]id 
    [R1-ui-console0]idle-timeout 0 0
    [R1-ui-console0]q
    [R1]int g0/0/0
    [R1-GigabitEthernet0/0/0]ip add 12.0.0.0 24
    [R1-GigabitEthernet0/0/0]ip add 12.0.0.1 24
    [R1-GigabitEthernet0/0/0]int g0/0/1
    [R1-GigabitEthernet0/0/1]ip add 13.0.0.1 24
    [R1-GigabitEthernet0/0/1]int loop 0 
    [R1-LoopBack0]ip add 1.1.1.1 32
    [R1-LoopBack0]q
    [R1]bgp 100
    [R1-bgp]peer 
    [R1-bgp]peer 1.1.1.1 advertise-community
    [R1-bgp]peer 1.1.1.1 advertise-ext-community
    [R1-bgp]peer 1.1.1.1 as-number 200
    Warning: Local interface is already configured with this address.
    [R1-bgp]peer 2.2.2.2 as-number 200
    [R1-bgp]peer 2.2.2.2 connect-interface LoopBack 0
    [R1-bgp]peer 2.2.2.2 next-hop-invariable
    [R1-bgp]peer 2.2.2.2 ebgp-max-hop 2
    [R1-bgp]peer 3.3.3.3 as-path-filter
    [R1-bgp]peer 3.3.3.3 as-number 200
    [R1-bgp]peer 3.3.3.3 connect-interface LoopBack 0
    [R1-bgp]peer 3.3.3.3 ebgp-max-hop 2
    [R1-bgp]q
    [R1]ip route-static 2.2.2.2 32 12.0.0.2
    [R1]ip route-static 3.3.3.3 32 13.0.0.3
    [R1]bgp 100
    [R1-bgp]network 2.2.2.2 32
    [R1-bgp]network 1.1.1.1 32
    [R1-bgp]network 3.3.3.3 32

R2:
    <Huawei>u t m 
    Info: Current terminal monitor is off.
    <Huawei>sys 
    <Huawei>system-view 
    Enter system view, return user view with Ctrl+Z.
    [Huawei]sys 
    [Huawei]sysname R2
    [R2]us 
    [R2]user-int 
    [R2]user-interface co 
    [R2]user-interface console 0
    [R2-ui-console0]id 
    [R2-ui-console0]idle-timeout 0 0
    [R2-ui-console0]q
    [R2]int g0/0/0
    [R2-GigabitEthernet0/0/0]ip add 12.0.0.2 24
    [R2-GigabitEthernet0/0/0]int g0/0/1
    [R2-GigabitEthernet0/0/1]ip add 24.0.0.2 24
    [R2-GigabitEthernet0/0/1]int loop 0
    [R2-LoopBack0]ip add 2.2.2.2 32
    [R2-LoopBack0]q
    [R2]osp 
    [R2]ospf 1
    R2-ospf-1]are 0
    [R2-ospf-1-area-0.0.0.0]net 
    [R2-ospf-1-area-0.0.0.0]network 24.0.0.0 0.0.0.255
    [R2-ospf-1-area-0.0.0.0]ne 
    [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]q
    [R2-ospf-1]bgp 200
    [R2-bgp]peer 1.1.1.1 as-number 100
    R2-bgp]peer 1.1.1.1 connect-interface LoopBack 0
    [R2-bgp]peer 1.1.1.1 ebgp-max-hop 2
    [R2-bgp]peer 4.4.4.4 as-number 200
    [R2-bgp]peer 4.4.4.4 connect-interface LoopBack 0
    [R2-bgp]peer 4.4.4.4 next-hop-invariable
    [R2-bgp]peer 4.4.4.4 next-hop-local
    [R2-bgp]peer 3.3.3.3 as-number 200
    [R2-bgp]peer 3.3.3.3 connect-interface LoopBack 0
    [R2-bgp]peer 3.3.3.3 next-hop-invariable
    [R2-bgp]peer 3.3.3.3 next-hop-local
    [R2-bgp]q[R2]ip route-static 1.1.1.1 32 12.0.0.1
    [R2]bgp 200
    [R2-bgp]net 
    [R2-bgp]network 1.1.1.1 32
    R2-bgp]network 2.2.2.2 32
    [R2-bgp]network 4.4.4.4 32
    [R2-bgp]network 3.3.3.3 32

R3:
    <Huawei>u t m 
    Info: Current terminal monitor is off.
    <Huawei>sys 
    <Huawei>system-view 
    Enter system view, return user view with Ctrl+Z.
    [Huawei]sys 
    [Huawei]sysname R3
    [R3]us 
    [R3]user-int 
    [R3]user-interface co 
    [R3]user-interface console 0
    [R3-ui-console0]id 
    [R3-ui-console0]idle-timeout 0 0
    [R3-ui-console0]q
    [R3]int g0/0/1
    [R3-GigabitEthernet0/0/1]ip add 13.0.0.3 24
    [R3-GigabitEthernet0/0/1]int g0/0/0
    R3-GigabitEthernet0/0/0]ip add 34.0.0.3 24
    [R3-GigabitEthernet0/0/0]int loop 0
    [R3-LoopBack0]ip add 3.3.3.3 32
    [R3-LoopBack0]
    [R3-LoopBack0]q
    [R3]os 
    [R3]ospf 1
    [R3-ospf-1]are 
    [R3-ospf-1]area 0
    [R3-ospf-1-area-0.0.0.0]network 34.0.0.0 0.0.0.255
    [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]bgp 200
    [R3-bgp]peer 1.1.1.1 as-number 100
    [R3-bgp]peer 1.1.1.1 connect-interface LoopBack  0
    [R3-bgp]peer 1.1.1.1 ebgp-max-hop 2
    [R3-bgp]peer 2.2.2.2 as-number 200
    [R3-bgp]peer 2.2.2.2 connect-interface LoopBack 0
    [R3-bgp]peer 2.2.2.2 next-hop-invariable
    [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 LoopBack 0
    [R3-bgp]peer 4.4.4.4 next-hop-local
    [R3-bgp]q
    [R3]ip route-static 1.1.1.1 32 13.0.0.1
    [R3]bgp 200
    [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

R4:
    <Huawei>u t m 
    Info: Current terminal monitor is off.
    <Huawei>sys 
    <Huawei>system-view 
    Enter system view, return user view with Ctrl+Z.
    [Huawei]sys 
    [Huawei]sysname R4
    [R4]us 
    [R4]user-int 
    [R4]user-interface co 
    [R4]user-interface console 0
    [R4-ui-console0]id 
    [R4-ui-console0]idle-timeout 0 0
    [R4-ui-console0]q
    [R4]int g0/0/1
    [R4-GigabitEthernet0/0/1]ip add 24.0.0.4 24
    [R4-GigabitEthernet0/0/1]int g0/0/0
    [R4-GigabitEthernet0/0/0]ip add 34.0.0.4 24
    [R4-GigabitEthernet0/0/0]int loop 0
    [R4-LoopBack0]ip add 4.4.4.4 32
    [R4-LoopBack0]
    [R4-LoopBack0]q
    [R4]os 
    [R4]ospf 1
    [R4-ospf-1]are 
    [R4-ospf-1]area 0
    [R4-ospf-1-area-0.0.0.0]network 24.0.0.0 0.0.0.255
    [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 34.0.0.0 0.0.0.255
    [R4-ospf-1-area-0.0.0.0]bgp 200
    [R4-bgp]peer 2.2.2.2 as 
    [R4-bgp]peer 2.2.2.2 as-number 200
    R4-bgp]peer 2.2.2.2 connect-interface LoopBack 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 LoopBack 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 LoopBack 0
    [R4-bgp]peer 5.5.5.5 e 
    R4-bgp]peer 5.5.5.5 ebgp-max-hop 2
    [R4-bgp]
    [R4-bgp]q
    [R4]ip ro 
    [R4]ip route-static
    [R4]ip route
    [R4]ip route-static 5.5.5.5 32 45.0.0.5
    [R4]bgp 200
    [R4-bgp]net 
    [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
    Info: The network does not exist.
    [R4-bgp]q
    [R4]int g0/0/2
    [R4-GigabitEthernet0/0/2]ip add 45.0.0.4 24
    [R4-GigabitEthernet0/0/2]q
    [R4]bgp 200
    [R4-bgp]net 
    [R4-bgp]network 5.5.5.5 32

R5:
    <Huawei>u t m 
    Info: Current terminal monitor is off.
    <Huawei>sys 
    <Huawei>system-view 
    Enter system view, return user view with Ctrl+Z.
    [Huawei]sys 
    [Huawei]sysname R5
    [R5]us 
    [R5]user-int 
    [R5]user-interface co 
    [R5]user-interface console 0
    [R5-ui-console0]id 
    [R5-ui-console0]idle-timeout 0 0
    [R5-ui-console0]q
    [R5]int g0/0/2
    [R5-GigabitEthernet0/0/2]ip add 45.0.0.5 24
    [R5-GigabitEthernet0/0/2]int loop 0
    [R5-LoopBack0]ip add 5.5.5.5 32
    [R5-LoopBack0]
    [R5-LoopBack0]q
    [R5]bgp 300
    [R5-bgp]peer 4.4.4.4 as-number 200
    R5-bgp]peer 4.4.4.4 connect-interface LoopBack 0 
    [R5-bgp]peer 4.4.4.4 ebgp-max-hop 2
    5]ip route-static 4.4.4.4 32 45.0.0.4
    [R5]bgp 300
    [R5-bgp]network 4.4.4.4 32
    [R5-bgp]network 5.5.5.5 32

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 3]

**RPG选路：local——prefernce IBGP之间传递(越大越优先）**
    R4从R1路径：从2走到1.现在改为从3走到1：
    在R4中设置：
    route-policy lop permit node 10
    [R4-route-policy]apply local-preference 222
    [R4-route-policy]q
    [R4]bgp 200
    R4-bgp]peer 3.3.3.3 route-policy lop import 
    [R4]q
    <R4>re 
    <R4>refresh bgp all im 
    <R4>refresh bgp all import

因为路径是R4————R3————R1.因为是越大越优先，因为在R4中配置，路径从R3—R4，所以是Import，

再查看dis BGP routing-table:

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 4]

**AS——PATH 用于IBDG，EBDG长度越少越优**

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 5]

在R1中查询路径：目前路径为4到2.想改为4到3  最后到1.
    因为长度是越少越优，指令是添加长度，所以在R2 或者R1中配置
    选择R2中配置：
    [R2]rou 
    [R2]route
    [R2]route-policy as 
    [R2]route-policy as p 
    [R2]route-policy as permit nod 
    [R2]route-policy as permit node 10
    Info: New Sequence of this List.
    [R2-route-policy]app 
    [R2-route-policy]apply as 
    [R2-route-policy]apply as-path 123 123 add 
    [R2-route-policy]apply as-path 123 123 additive 
    [R2-route-policy]q
    [R2]bgp 200
    [R2-bgp]peer 1.1.1.1 p 
    [R2-bgp]peer 1.1.1.1 password
    [R2-bgp]peer 1.1.1.1 r 
    [R2-bgp]peer 1.1.1.1 route-policy as e 
    [R2-bgp]peer 1.1.1.1 route-policy as export 
    [R2-bgp]q
    [R2]q
    <R2>re 
    <R2>reboot
    <R2>refresh bgp all e 
    <R2>refresh bgp all export

配置完，在R1中查表：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 6]  
因为路径是R4----R2 ------R1,路径是从R2到R1，从R2出站，R1进站，因在R２中设置所以为出站：export

**MED：可选非传递属性，EBGP传递，（越小越优先）**  
要求R１　从４－－－３，现在是４－－－２

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 7]

路径是从R4——R2——R1，现在要改为R4——R3——R1，因为路径是从R1---R 2,在R1上配，路径再从R1----R2     就是在R1中配置，R1就是import
    
    R1：
    R1]rou 
    [R1]route
    [R1]route-policy me 
    [R1]route-policy med 
    [R1]route-policy med per 
    [R1]route-policy med permit no 
    [R1]route-policy med permit node 10
    Info: New Sequence of this List.
    -route-policy]apply cost + 500
    [R1-route-policy]q
    [R1]bgp 100
    R1-bgp]peer 2.2.2.2 route-policy med import 
    q
    <R1>ref 
    <R1>refresh bgp all im 
    <R1>refresh bgp all import

因为越小越优先，要求是从３走，所以把R２上的数值加大：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 8]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center]: /images/20210726/ea80c7560ce94af8b86b927989474781.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 1]: /images/20210726/44cad66c05424b7ca30440cafb020d82.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 2]: /images/20210726/a66b58931d7249bbba876482dfb94b23.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 3]: /images/20210726/c2529a750a2b4fd6aa6ebbadc911da7d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 4]: /images/20210726/8c1bfb5bddac4782af99f244df93f923.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 5]: /images/20210726/ef9ef6f2058a49de944d9f882af8b5a0.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 6]: /images/20210726/9c1d009b835b4a20a5d72465016e5225.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 7]: /images/20210726/4f54dcba7f5e4002b57e71ba081dc921.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dzeHlp_size_16_color_FFFFFF_t_70_pic_center 8]: /images/20210726/ae466086044342e792176b21049870be.png