HCIP实验（BGP基础）

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最新推荐文章于 2025-05-30 04:55:24 发布

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本文链接：https://blog.youkuaiyun.com/weixin_72632154/article/details/132252687

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该博客围绕网络实验展开，介绍了实验拓扑、需求、步骤和测试。实验需求是除R5的环回5.5.5.0外，其他环回可互相访问。实验步骤包括合理配置ip、完成AS通信、建立邻居关系、BGP路由宣告等，还解决了3个选路问题，最后进行测试。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

一、实验拓扑

二、实验需求

除R5的环回5.5.5.0环回外，其他所有的环回均可互相访问

三、实验步骤

合理配置ip地址；完成AS通信；建立邻居关系；BGP路由宣告；3个选路问题；结果测试；

ip配置：

[r1]int g0/0/0
[r1-GigabitEthernet0/0/0]ip add 12.1.1.1 24
Aug 10 2023 19:26:22-08:00 r1 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP 
on the interface GigabitEthernet0/0/0 has entered the UP state. 
[r1-GigabitEthernet0/0/0]int l0
[r1-LoopBack0]ip add 1.1.1.1 24
 

[r2]int g0/0/0
[r2-GigabitEthernet0/0/0]ip add 12.1.1.2 24
Aug 10 2023 19:27:31-08:00 r2 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP 
on the interface GigabitEthernet0/0/0 has entered the UP state. 
[r2-GigabitEthernet0/0/0]int g0/0/1
[r2-GigabitEthernet0/0/1]ip add 23.1.1.1 24
Aug 10 2023 19:29:27-08:00 r2 %%01IFNET/4/LINK_STATE(l)[1]:The line protocol IP 
on the interface GigabitEthernet0/0/1 has entered the UP state. 
[r2-GigabitEthernet0/0/1]int l0
[r2-LoopBack0]ip add 2.2.2.2 24
 

[r3]int g0/0/0
[r3-GigabitEthernet0/0/0]ip add 23.1.1.2 24
Aug 10 2023 19:32:42-08:00 r3 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP 
on the interface GigabitEthernet0/0/0 has entered the UP state. 
[r3-GigabitEthernet0/0/0]int g0/0/1
[r3-GigabitEthernet0/0/1]ip add 34.1.1.1 24
Aug 10 2023 19:33:51-08:00 r3 %%01IFNET/4/LINK_STATE(l)[1]:The line protocol IP 
on the interface GigabitEthernet0/0/1 has entered the UP state. 
[r3-GigabitEthernet0/0/1]int l0
[r3-LoopBack0]ip add 3.3.3.3 24
 

[r4]int g0/0/0
[r4-GigabitEthernet0/0/0]ip add 34.1.1.2 24
Aug 10 2023 19:34:45-08:00 r4 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP 
on the interface GigabitEthernet0/0/0 has entered the UP state. 
[r4-GigabitEthernet0/0/0]int g0/0/1
[r4-GigabitEthernet0/0/1]ip add 45.1.1.1 24
Aug 10 2023 19:35:09-08:00 r4 %%01IFNET/4/LINK_STATE(l)[1]:The line protocol IP 
on the interface GigabitEthernet0/0/1 has entered the UP state. 
[r4-GigabitEthernet0/0/1]int g0/0/2
[r4-GigabitEthernet0/0/2]ip add 54.1.1.1 24
[r4-GigabitEthernet0/0/2]
Aug 10 2023 19:35:35-08:00 r4 %%01IFNET/4/LINK_STATE(l)[2]:The line protocol IP 
on the interface GigabitEthernet0/0/2 has entered the UP state. 
[r4-GigabitEthernet0/0/2]int l0
[r4-LoopBack0]ip add 4.4.4.4 24
 

[r5]int g0/0/0
[r5-GigabitEthernet0/0/0]ip add 45.1.1.2 24
Aug 10 2023 19:36:47-08:00 r5 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP 
on the interface GigabitEthernet0/0/0 has entered the UP state. 
[r5-GigabitEthernet0/0/0]int g0/0/1
[r5-GigabitEthernet0/0/1]ip add 54.1.1.2 24
[r5-GigabitEthernet0/0/1]
Aug 10 2023 19:37:10-08:00 r5 %%01IFNET/4/LINK_STATE(l)[1]:The line protocol IP 
on the interface GigabitEthernet0/0/1 has entered the UP state. 
[r5-GigabitEthernet0/0/1]int l0
[r5-LoopBack0]ip add 5.5.5.5 24
[r5]int LoopBack 1
[r5-LoopBack1]ip add 99.1.1.1 24

完成AS通信（AS2需要宣告OSPF）：

R2
[r2]os    
[r2]ospf 1 rou    
[r2]ospf 1 router-id 2.2.2.2
[r2-ospf-1]are    
[r2-ospf-1]area 0
[r2-ospf-1-area-0.0.0.0]net    
[r2-ospf-1-area-0.0.0.0]network 2.2.2.0 0.0.0.255
[r2-ospf-1-area-0.0.0.0]net    
[r2-ospf-1-area-0.0.0.0]network 23.1.1.0 0.0.0.255

R3
[r3]os    
[r3]ospf 1 rou    
[r3]ospf 1 router-id 3.3.3.3
[r3-ospf-1]ar    
[r3-ospf-1]area 0
[r3-ospf-1-area-0.0.0.0]3.3.3.0 0.0.0.255
[r3-ospf-1-area-0.0.0.0]net    
[r3-ospf-1-area-0.0.0.0]network 3.3.3.0 0.0.0.255
[r3-ospf-1-area-0.0.0.0]net    
[r3-ospf-1-area-0.0.0.0]network 23.1.1.0 0.0.0.255
[r3-ospf-1-area-0.0.0.0]net    
[r3-ospf-1-area-0.0.0.0]network 34.1.1.0 0.0.0.255

R4
[r4]os    
[r4]ospf 1 rou    
[r4]ospf 1 router-id 4.4.4.4
[r4-ospf-1]ar    
[r4-ospf-1]area 0
[r4-ospf-1-area-0.0.0.0]net    
[r4-ospf-1-area-0.0.0.0]network 4.4.4.0 0.0.0.255
[r4-ospf-1-area-0.0.0.0]net    
[r4-ospf-1-area-0.0.0.0]network 34.1.1.0 0.0.0.255

建立邻居关系：

1.r1与r2建立邻居

R1
[r1]bgp 1
[r1-bgp]rou    
[r1-bgp]route    
[r1-bgp]router-id 1.1.1.1
[r1-bgp]pe    
[r1-bgp]peer 12.1.1.2 as    
[r1-bgp]peer 12.1.1.2 as-number

R2
[r2]bgp 2
[r2-bgp]router    
[r2-bgp]router-id  2.2.2.2
[r2-bgp]p    
[r2-bgp]peer 12.1.1.1 a    
[r2-bgp]peer 12.1.1.1 as    
[r2-bgp]peer 12.1.1.1 as-number 1

2.AS2内部建立IBGP邻居关系：

1)r2与r3：

R2
[r2]bgp 2
[r2-bgp]rou    
[r2-bgp]router    
[r2-bgp]router-id  2.2.2.2
[r2-bgp]p    
[r2-bgp]peer 12.1.1.1 a    
[r2-bgp]peer 12.1.1.1 as    
[r2-bgp]peer 12.1.1.1 as-number 1
[r2-bgp]pe    
[r2-bgp]peer 3.3.3.3 as    
[r2-bgp]peer 3.3.3.3 as-number 2
[r2-bgp]pe    
[r2-bgp]peer 3.3.3.3 con    
[r2-bgp]peer 3.3.3.3 connect-interface loo    
[r2-bgp]peer 3.3.3.3 connect-interface LoopBack 0

R3
[r3]bg    
[r3]bgp 2
[r3-bgp]rou    
[r3-bgp]router    
[r3-bgp]router-id  3.3.3.3
[r3-bgp]pe    
[r3-bgp]peer 2.2.2.2 as    
[r3-bgp]peer 2.2.2.2 as-number 2
[r3-bgp]pe    
[r3-bgp]peer 2.2.2.2 con    
[r3-bgp]peer 2.2.2.2 connect-interface loo    
[r3-bgp]peer 2.2.2.2 connect-interface LoopBack 0

2）r3与r4：

R3
[r3]bgp 2
[r3-bgp]pe    
[r3-bgp]peer 4.4.4.4 as    
[r3-bgp]peer 4.4.4.4 as-number 2
[r3-bgp]pe    
[r3-bgp]peer 4.4.4.4 con    
[r3-bgp]peer 4.4.4.4 connect-interface loo    
[r3-bgp]peer 4.4.4.4 connect-interface LoopBack 0

R4
[r4]bgp 2
[r4-bgp]rou    
[r4-bgp]router    
[r4-bgp]router-id 4.4.4.4
[r4-bgp]p    
[r4-bgp]peer 3.3.3.3 as    
[r4-bgp]peer 3.3.3.3 as-nu    
[r4-bgp]peer 3.3.3.3 as-number 2
[r4-bgp]pe    
[r4-bgp]peer 3.3.3.3 con    
[r4-bgp]peer 3.3.3.3 connect-interface loo    
[r4-bgp]peer 3.3.3.3 connect-interface LoopBack 0

3）r4与r5（有两条链路相连，建立EBGP邻居使用环回建立，为保证r4r5环回能正常通信。所以使用静态路由）：

R4
[r4]ip rou    
[r4]ip route-st    
[r4]ip route-static 5.5.5.0 24 45.1.1.2
[r4]ip rou    
[r4]ip route-st    
[r4]ip route-static 5.5.5.0 24 54.1.1.2

R5
[r5]ip rou    
[r5]ip route-st    
[r5]ip route-static 4.4.4.0 24 45.1.1.1
[r5]ip rou    
[r5]ip route-st    
[r5]ip route-static 4.4.4.0 24 54.1.1.1

R4
[r4]bgp 2
[r4-bgp]pe    
[r4-bgp]peer 5.5.5.5 as    
[r4-bgp]peer 5.5.5.5 as-number 3
[r4-bgp]pe    
[r4-bgp]peer 5.5.5.5 con    
[r4-bgp]peer 5.5.5.5 connect-interface lo    
[r4-bgp]peer 5.5.5.5 connect-interface LoopBack 0

R5
[r5]bgp 3
[r5-bgp]rou    
[r5-bgp]router    
[r5-bgp]router-id 5.5.5.5
[r5-bgp]pe    
[r5-bgp]peer 4.4.4.4 as    
[r5-bgp]peer 4.4.4.4 as-number 2
[r5-bgp]pe    
[r5-bgp]peer 4.4.4.4 con    
[r5-bgp]peer 4.4.4.4 connect-interface lo    
[r5-bgp]peer 4.4.4.4 connect-interface LoopBack 0
EBGP邻居间默认TTL值为1，IBGP为255，使用两个EBGP邻居间两个直连的物理接口，但是实际上使用的是环回建立邻居关系，所以需要修改TTL的值为2

R4
[r4-bgp]p    
[r4-bgp]peer 5.5.5.5 eb    
[r4-bgp]peer 5.5.5.5 ebgp-max-hop 2

R5
[r5-bgp]p    
[r5-bgp]peer 4.4.4.4 eb    
[r5-bgp]peer 4.4.4.4 ebgp-max-hop 2

BGP宣告：

AS1--R1
[r1]bg    
[r1]bgp 1
[r1-bgp]net    
[r1-bgp]network 1.1.1.0 24
[r1-bgp]network 12.1.1.0 24

AS2--R2
[r2]bg    
[r2]bgp 2
[r2-bgp]net    
[r2-bgp]network 2.2.2.0 24
[r2-bgp]network 12.1.1.0 24
[r2-bgp]net    
[r2-bgp]network 23.1.1.0 24

AS2--R3
[r3]bg    
[r3]bgp 2
[r3-bgp]net    
[r3-bgp]network 3.3.3.0 24
[r3-bgp]network 23.1.1.0 24
[r3-bgp]net    
[r3-bgp]network 34.1.1.0 24
[r3-bgp]

AS2--R4
[r4]bgp  2
[r4-bgp]ne    
[r4-bgp]network 4.4.4.0 24
[r4-bgp]network 34.1.1.0 24
[r4-bgp]net    
[r4-bgp]network 45.1.1.0 24
[r4-bgp]net    
[r4-bgp]network 54.1.1.0 24

AS3--R5
[r5]bgp 3
[r5-bgp]net    
[r5-bgp]network 5.5.5.0 24
[r5-bgp]network 45.1.1.0 24
[r5-bgp]net    
[r5-bgp]network 54.1.1.0 24

选路问题（r4学习不到r2的路由，由于IBGP水平分割，需要r2给r4建立独立的IBGP）：

R2
[r2]bgp  2
[r2-bgp]pe    
[r2-bgp]peer 4.4.4.4 ad    
[r2-bgp]peer 4.4.4.4 as    
[r2-bgp]peer 4.4.4.4 as-nu    
[r2-bgp]peer 4.4.4.4 as-number 2
[r2-bgp]pe    
[r2-bgp]peer 4.4.4.4 con    
[r2-bgp]peer 4.4.4.4 connect-interface lp    
[r2-bgp]peer 4.4.4.4 connect-interface lo    
[r2-bgp]peer 4.4.4.4 connect-interface LoopBack 0

R4
[r4]bgp 2
[r4-bgp]pe    
[r4-bgp]peer 2.2.2.2 ad-nu    
[r4-bgp]peer 2.2.2.2 as-nu    
[r4-bgp]peer 2.2.2.2 as-number 2
[r4-bgp]p    
[r4-bgp]peer 2.2.2.2 con    
[r4-bgp]peer 2.2.2.2 connect-interface lo    
[r4-bgp]peer 2.2.2.2 connect-interface LoopBack 0

r3学习到的r1到r5的路由不是最优（需要将R2与R4将路由条目传递给下一个邻居时，修改下一跳为本地地址）：

R2 
[r2]bgp 2
[r2-bgp]p    
[r2-bgp]peer 3.3.3.3 ne    
[r2-bgp]peer 3.3.3.3 next-hop-local
[r2-bgp]p    
[r2-bgp]peer 4.4.4.4 ne    
[r2-bgp]peer 4.4.4.4 next-hop-local

R4
[r4]bgp 2
[r4-bgp]p    
[r4-bgp]peer 2.2.2.2 ne    
[r4-bgp]peer 2.2.2.2 next-hop-local
[r4-bgp]p    
[r4-bgp]peer 3.3.3.3 ne    
[r4-bgp]peer 3.3.3.3 next-hop-local

出现悖论（查看R4的BGP表会发现到5环回5.5.5.0不优，应该把之前在R4为了和R5建邻的静态修改一下，将原来的24位改为32位）：

[r4]und    
[r4]undo ip rou    
[r4]undo ip route-st    
[r4]undo ip route-static 5.5.5.0 24
[r4]ip  rou    
[r4]ip  route-st    
[r4]ip  route-static 5.5.5.5 32 45.1.1.2
[r4]ip rou    
[r4]ip route-st    
[r4]ip route-static 5.5.5.5 32 54.1.1.2