OSPF(eNSP)

OSPF(Open Shortest Path First)

开放式最短路径优先

由IETF组织开发

基于链路状态的内部网关协议

版本

IPv4：OSPF Version 2（RFC2328）

IPv6：OSPF Version 3（RFC2740）

“why” 需要 “ospf” ？

上世纪，传统Internet 路由协议RIP

其基于距离矢量的算法

仅根据跳数而忽略其他因数

OSPF则通过cost为度量值

需要综合带宽、跳数...

作为链路状态协议

它将链路作为路由接口

进行接口与相邻路由关系的描述

在路由的自治系统中

通过给链路分配区域

区域通过向周边发送报文

实现自治系统自动管理

A

[A]interface GigabitEthernet 0/0/1	
[A-GigabitEthernet0/0/1]ip address 192.168.1.1 24
[A]ospf 1 router-id 1.1.1.1
[A-ospf-1]area 0
[A-ospf-1-area-0.0.0.0]network 192.168.1.0 0.0.0.255

B

[B]interface GigabitEthernet 0/0/1	
[B-GigabitEthernet0/0/1]ip address 192.168.1.2 24
[B]interface GigabitEthernet 0/0/2	
[B-GigabitEthernet0/0/2]ip address 192.168.2.1 24	
[B]ospf 1 router-id 2.2.2.2
[B-ospf-1]area 0
[B-ospf-1-area-0.0.0.0]network 192.168.1.0 0.0.0.255
[B-ospf-1]area 1	
[B-ospf-1-area-0.0.0.1]network 192.168.2.0 0.0.0.255

C

[C]interface GigabitEthernet 0/0/2
[C-GigabitEthernet0/0/2]ip address 192.168.2.2 24	
[C]ospf 1 router-id 3.3.3.3	
[C-ospf-1]area 1
[C-ospf-1-area-0.0.0.1]network 192.168.2.0 0.0.0.255

查看OSPF邻居

[B]display ospf peer

	 OSPF Process 1 with Router ID 2.2.2.2
		 Neighbors 

 Area 0.0.0.0 interface 192.168.1.2(GigabitEthernet0/0/1)'s neighbors
 Router ID: 192.168.1.1      Address: 192.168.1.1     
   State: Full  Mode:Nbr is  Master  Priority: 1
   DR: 192.168.1.1  BDR: 192.168.1.2  MTU: 0    
   Dead timer due in 37  sec 
   Retrans timer interval: 5 
   Neighbor is up for 00:03:38     
   Authentication Sequence: [ 0 ] 

		 Neighbors 

 Area 0.0.0.1 interface 192.168.2.1(GigabitEthernet0/0/2)'s neighbors
 Router ID: 3.3.3.3          Address: 192.168.2.2     
   State: Full  Mode:Nbr is  Master  Priority: 1
   DR: 192.168.2.1  BDR: 192.168.2.2  MTU: 0    
   Dead timer due in 37  sec 
   Retrans timer interval: 5 
   Neighbor is up for 00:01:28     
   Authentication Sequence: [ 0 ] 

查看OSPF路由

[B]dis ospf routing

	 OSPF Process 1 with Router ID 2.2.2.2
		  Routing Tables 

 Routing for Network 
 Destination        Cost  Type       NextHop         AdvRouter       Area
 192.168.1.0/24     1     Transit    192.168.1.2     2.2.2.2         0.0.0.0
 192.168.2.0/24     1     Transit    192.168.2.1     2.2.2.2         0.0.0.1

 Total Nets: 2  
 Intra Area: 2  Inter Area: 0  ASE: 0  NSSA: 0 

开启ospf并设置进程为1，配置自治区的路由ID

ospf 1 router-id 1.1.1.1

配置路由管理的自治区，0为最高级自治区

area 0

通告该自治区的网络

network 192.168.1.0 0.0.0.255