实验要求

1. R2-7 每台路由器均存在一个环回接口用于建邻，同时还存在一个环回来代表连接用户的接口
2. 连接用户的接口网络需要可以和 R1/8 的环回通讯
3. AS2 网段地址为 172.16.0.0/16，要求减少路由条目
   

实验过程

IP地址划分

在AS 2中，基于 172.16.0.0/16 进行IP地址划分
首先6个环回建邻接口：

172.16.0.2/32
172.16.0.3/32
172.16.0.4/32
172.16.0.5/32
172.16.0.6/32
172.16.0.7/32

然后每台路由器上都有模拟用户的网段：

172.16.2.0/24
172.16.3.0/24
172.16.4.0/24
172.16.5.0/24
172.16.6.0/24
172.16.7.0/24

最后路由器间的网段公有6个：

172.16.1.0/24
-------------
172.16.1.0/27
172.16.1.32/27
172.16.1.64/27
172.16.1.96/27
172.16.1.128/27
172.16.1.160/27
172.16.1.192/27(弃)
172.16.1.224/27(弃)

OSPF

路由表展示：

建邻（联邦+反射器）

//R1 - AS 1
bgp 1                                     
 router-id 1.1.1.1                        
 peer 12.1.1.2 as-number 2                
 # 
 ipv4-family unicast                      
  undo synchronization                    
  peer 12.1.1.2 enable
//R2 - AS 64512
bgp 64512                                 //联邦
 router-id 2.2.2.2                        
 confederation id 2                       
 confederation peer-as 64513              
 peer 12.1.1.1 as-number 1                
 peer 172.16.0.3 as-number 64512          
 peer 172.16.0.3 connect-interface LoopBack0
 peer 172.16.0.5 as-number 64513          
 peer 172.16.0.5 ebgp-max-hop 2           
 peer 172.16.0.5 connect-interface LoopBack0
 # 
 ipv4-family unicast                      
  undo synchronization                    
  peer 12.1.1.1 enable                    
  peer 172.16.0.3 enable                  
  peer 172.16.0.3 next-hop-local          
  peer 172.16.0.5 enable
  peer 172.16.0.5 next-hop-local
//R3 - AS 64512
bgp 64512                                 
 router-id 3.3.3.3                        
 confederation id 2                       
 peer 172.16.0.2 as-number 64512          
 peer 172.16.0.2 connect-interface LoopBack0
 peer 172.16.0.4 as-number 64512          
 peer 172.16.0.4 connect-interface LoopBack0
 # 
 ipv4-family unicast                      
  undo synchronization                    
  peer 172.16.0.2 enable                  
  peer 172.16.0.2 reflect-client          //反射器
  peer 172.16.0.4 enable
//R4 - AS 64512
bgp 64512                                 
 router-id 4.4.4.4                        
 confederation id 2                       
 confederation peer-as 64513              
 peer 172.16.0.3 as-number 64512          
 peer 172.16.0.3 connect-interface LoopBack0
 peer 172.16.0.7 as-number 64513          
 peer 172.16.0.7 ebgp-max-hop 2           
 peer 172.16.0.7 connect-interface LoopBack0
 # 
 ipv4-family unicast                      
  undo synchronization                    
  peer 172.16.0.3 enable                  
  peer 172.16.0.7 enable
//R5-8 同上

宣告路由

//R2
bgp 64512
 ipv4-family unicast                      
  undo synchronization                    
  network 172.16.2.0 255.255.255.0        
  network 172.16.3.0 255.255.255.0        
  network 172.16.4.0 255.255.255.0        
  network 172.16.5.0 255.255.255.0        
  network 172.16.6.0 255.255.255.0        
  network 172.16.7.0 255.255.255.0
//R7
bgp 64513
 ipv4-family unicast                      
  undo synchronization                    
  network 172.16.2.0 255.255.255.0        
  network 172.16.3.0 255.255.255.0        
  network 172.16.4.0 255.255.255.0        
  network 172.16.5.0 255.255.255.0        
  network 172.16.6.0 255.255.255.0        
  network 172.16.7.0 255.255.255.0

BGP展示：

聚合

[R2]ip ip-prefix aa deny 172.16.1.0 24
[R2]ip ip-prefix aa permit 0.0.0.0 0 le 32
[R2]bgp 64512
[R2-bgp]aggregate 172.16.0.0 16 detail-suppressed	//聚合
[R2-bgp]peer 12.1.1.1 ip-prefix aa export			//调用前缀列表

BGP表展示：

连通性测试：
R1环回 ping R8环回

R1环回 ping AS 2内部环回（R7）