OSPF 在企业网中的应用
ospfOpen Shortest Path First（开放昀短路由优先协议）的缩写。它是 IETF组织开发的一个基于链路状态的自治系统内部路由协议。现在普遍使用的是版本 2（RFC1583），ospf有以下主要特性：
1. 适应范围：支持各种规模的网络，昀多可支持几千台路由器。
2. 快速收敛：在网络的拓扑结构发生变化后立即发送更新报文，使这一变化在自治系统中同步。
3. 无自环： OSPF根据收集到的链路状态用昀短路径树算法计算路由，从算法上本身保证了不会生成自环路由。
4. 区域划分：允许自治系统的网络被划分成区域来管理，区域间传送的路由信息被进一步抽象，从而减少了占用的网络带宽。。
5. OSPF路由协议支持路由验证，只有互相通过路由验证的路由器之间才能交换路由信息，提高网络的安全性，
6. OSPF路由协议对负载分担的支持性能较好。
7. 以组播地址发送报文，动态路由协议为了能够自动找到网络中的邻居，通常都是以广播的地址来发送。RIP使用广播报文来发送给网络上所有的设备，所以在网络上的所有设备受到此报文后都需要做相应的处理，但是在实际应用中，并不是所有的设备都需要接受这种报文。因此，这种周期性以广播形式发送报文的形式对它就产生了一定的干扰。同时，由于这种报文会定期的发送，在一定程度上也占用了宝贵的带宽资源。后来，随着各种技术的不断提升和发展，出现了以组播地址来发送协议报文的形式。比如： OSPF使用224.0.0.5来发送，EIGRP使用224.0.0.2来发送。所以，OSPF采用组播地址来发送，只有运行OSPF协议的设备才会接受发送来的报文，其他设备不参与接收。
由于ospf有以上特性，因此，被应用于绝大多数企业网络中。下面我们通过一个案例，来了解ospf在企业网络中的应用。
案例
R1 : 运行截图、 配置
[R1]dis cu
Now create configuration...
Current configuration
!
version 1.74
local-user user1 service-type administrator password simple 123
sysname R1
firewall enable
aaa-enable
aaa accounting-scheme optional
!
interface Aux0
async mode flow
link-protocol ppp
!
interface Ethernet0
loopback
ip address 192.168.1.1 255.255.255.0
ospf enable are a 0.0.0 .1
!
interface Serial0
link-protocol ppp
ip address 192.168.2.1 255.255.255.0
ospf enable are a 0.0.0 .1
!
interface Serial1
link-protocol ppp
!
interface LoopBack1
ip address 192.168.8.1 255.255.255.0
!
quit
rip
network 192.168.8.0
network 192.168.7.0
!
quit
!
ospf enable
!
quit
!
return
R2 : 运行截图、 配置
[r2]dis cu
Now create configuration...
Current configuration
!
version 1.74
local-user user1 service-type administrator password simple 123
sysname r2
undo pos-server addr-switch
firewall enable
aaa-enable
aaa accounting-scheme optional
!
interface Aux0
async mode flow
link-protocol ppp
!
interface Ethernet0
ip address 192.168.6.1 255.255.255.0
!
interface Ethernet1
!
interface Serial0
clock DTECLK1
link-protocol ppp
ip address 192.168.2.2 255.255.255.0
ospf enable are a 0.0.0 .1
!
interface Serial1
clock DTECLK1
link-protocol ppp
ip address 192.168.3.1 255.255.255.0
ospf enable are a 0.0.0 .0
!
interface Async0
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async1
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async2
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async3
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async4
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async5
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async6
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async7
physical-mode async
async mode protocol
link-protocol ppp
!
interface LoopBack1
ip address 192.168.5.1 255.255.255.0
!
interface Null0
!
quit
rip
network 192.168.6.0
import-route static cost 1
!
quit
!
ospf enable
import-route direct
import-route rip
!
quit
!
quit
ip route-static 0.0.0 .0 0.0.0.0 Null 0 preference 60
!
return
R3 运行截图、 配置
int s 1
ip add 192.168.3.2 24
shutdown
undo shutdown
quit
int s 0
ip add 192.168.4.1 24
shutdown
undo shutdown
quit
ospf enable
quit
int s 1
ospf enable area 0
quit
int s 0
ospf enable area 2
quit
ospf
stub cost 100 area 2 no-summary
quit
R10 ：运行截图、 配置
int s 1
ip add 192.168.4.2 24
shutdown
undo shutdown
quit
int eth 0
ip add 192.168.5.1 24
loopback
quit
ospf enable
quit
int s 1
ospf enable area 2
quit
int eth 0
ospf enable area 2
quit
ospf
stub cos 100 area 2
quit
R5 ：运行截图、 配置
dis cu
Now create configuration...
Current configuration
!
version 1.74
local-user user1 service-type administrator password simple 123
sysname R5
undo pos-server addr-switch
firewall enable
aaa-enable
aaa accounting-scheme optional
!
controller e1 0
!
interface Aux0
async mode flow
link-protocol ppp
!
interface Ethernet0
ip address 192.168.6.2 255.255.255.0
!
interface Ethernet1
ip address 192.168.7.1 255.255.255.0
!
interface Serial0
link-protocol ppp
ip address 192.168.3.1 255.255.255.0
shutdown
!
interface Serial1
link-protocol ppp
!
quit
rip
network 192.168.7.0
network 192.168.6.0
!
quit
!
return
R6 : 运行截图、 配置
]dis cu
Now create configuration...
Current configuration
!
version 1.74
sysname R6
firewall enable
aaa-enable
aaa accounting-scheme optional
!
interface Aux0
async mode flow
link-protocol ppp
!
interface Ethernet0
ip address 192.168.7.2 255.255.255.0
!
interface Ethernet1
ip address 192.168.5.2 255.255.255.0
!
interface Serial0
link-protocol ppp
ip address 192.168.6.1 255.255.255.0
!
interface Serial1
link-protocol ppp
!
interface Async0
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async1
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async2
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async3
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async4
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async5
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async6
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async7
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async8
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async9
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async10
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async11
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async12
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async13
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async14
physical-mode async
async mode protocol
link-protocol ppp
!
interface Async15
physical-mode async
async mode protocol
link-protocol ppp
!
quit
rip
network 192.168.7.0
network 192.168.5.0
network 192.168.6.0
!
quit
!
return
原创、请勿转载！！！