OSPF基础介绍
一.RIP的缺陷
1.以跳数评估的路由并非最优路径
2.最大跳数16导致网络尺度小
3.收敛速度慢
4.更新发送全部路由表浪费网络资源
二.OSPF基本原理
1.什么是OSPF
a>.OSPF（Open Shortest Path First,开放最短路径有限）是IETF开发的基于链路状态的自治系统内部路由协议；
b>.OSPF仅传播对端设备不具备的路由信息，网络收敛迅速，并有效避免了网络资源浪费；
c>.OSPF直接工作于IP层之上，IP协议号为89；
d>.OSPF以组播地址发送协议包；
2. OSPF协议工作过程概述
a>.寻找邻居；
b>.建立邻接关系；
注意：上图中的DR和BDR是用来管理一个单区域的，上图中邻接关系数是10，如果都让OSPF来管理是会有很大的负载的，这个时候选举出DR和BDR（DR是管理者，当DR坏掉是有BDR路由器来取得所有权进行管理）来管理这些单区域，多条链路是的话需要选举出来DR和BDR，单挑链路是没有必要选举的，因为没有那么大的负载。
DR和BDR选举
DR,BDR选举规则总结：
1>.选举接口优先级，优先级越大越优先，被选DR，优先级第二，被选BDR.
2>.如果优先级一样，选route-id,越大优先.
3>.如果路由器没有设置route-id，那么选接口的ip地址，越大越优先。
注意：一个单区域中可以没有BDR，但是必须有DR!
c>.链路状态信息传递;
d.路由计算
3.OSPF协议分区域管理
4.OSPF协议区域LSA发布
三.配置OSPF
配置下图实验，让公司总部这太电脑能够访问各个机房的主机！
配置过程如下：
"兆维机房"配置如下：
1 "兆维机房"配置如下： 2 [Huawei]sysname zhaowei 3 [zhaowei]interface LoopBack 1 4 [zhaowei-LoopBack1]ip address 172.16.1.1 24 5 [zhaowei-LoopBack1]quit 6 [zhaowei]interface Ethernet 0/0/0 7 [zhaowei-Ethernet0/0/0]ip address 192.168.1.1 24 8 [zhaowei-Ethernet0/0/0]undo shutdown 9 [zhaowei-Ethernet0/0/0]quit 10 [zhaowei]interface Ethernet 0/0/0 11 [zhaowei-Ethernet0/0/0]ospf dr-priority 100 #设置优先级为100，这样使得其优先级最高，成为DR路由器 12 [zhaowei-Ethernet0/0/0]quit 13 [zhaowei]router id 1.1.1.1 14 [zhaowei]ospf 100 #配置进程号，这个可以自定义 15 [zhaowei-ospf-100]area 0 #定义区域 16 [zhaowei-ospf-100-area-0.0.0.0]network 192.168.1.0 0.0.0.255 #这个掩码（0.0.0.255）=广播地址（255.255.255.0）-这个 17 18 网段的子网掩码（255.255.255.0） 19 [zhaowei-ospf-100-area-0.0.0.0]network 172.16.1.1 0.0.0.0 #向外面宣告这个地址
"鲁谷机房"配置如下：
1 [Huawei]sysname lugu 2 [lugu]interface LoopBack 1 3 [lugu-LoopBack1]ip address 172.16.1.2 24 4 [lugu-LoopBack1]quit 5 [lugu]interface Ethernet 0/0/0 6 [lugu-Ethernet0/0/0]ip address 192.168.1.2 24 7 [lugu-Ethernet0/0/0]undo shutdown 8 [lugu-Ethernet0/0/0]quit 9 [lugu]router id 2.2.2.2 #配置路由的ID 10 [lugu]ospf 100 11 [lugu-ospf-100]area 0 12 [lugu-ospf-100-area-0.0.0.0]network 192.168.1.0 0.0.0.255 13 [lugu-ospf-100-area-0.0.0.0]network 172.16.1.2 0.0.0.0
"清华园机房"配置如下：
1 [Huawei]sysname qinghuayuan 2 [qinghuayuan]interface Ethernet 0/0/1 3 [qinghuayuan-Ethernet0/0/1]ip address 172.30.1.254 24 4 [qinghuayuan-Ethernet0/0/1]undo shutdown 5 [qinghuayuan-Ethernet0/0/1]quit 6 [qinghuayuan]interface Ethernet 0/0/0 7 [qinghuayuan-Ethernet0/0/0]ip address 192.168.1.3 24 8 [qinghuayuan-Ethernet0/0/0]undo shutdown 9 [qinghuayuan-Ethernet0/0/0]quit 10 [qinghuayuan]router id 3.3.3.3 11 [qinghuayuan]ospf 100 12 [qinghuayuan-ospf-100]area 0 13 [qinghuayuan-ospf-100-area-0.0.0.0]network 192.168.1.0 0.0.0.255 14 [qinghuayuan-ospf-100-area-0.0.0.0]network 172.30.1.0 0.0.0.255
"廊坊机房"配置如下：
1 [Huawei]sysname langfang 2 [langfang]interface LoopBack 1 3 [langfang-LoopBack1]ip address 172.16.1.4 24 4 [langfang-LoopBack1]quit 5 [langfang]interface Ethernet 0/0/0 6 [langfang-Ethernet0/0/0]ip address 192.168.1.4 24 7 [langfang-Ethernet0/0/0]undo shutdown 8 [langfang-Ethernet0/0/0]quit 9 [langfang]router id 4.4.4.4 10 [langfang]ospf 100 11 [langfang-ospf-100]area 0 12 [langfang-ospf-100-area-0.0.0.0]network 192.168.1.0 0.0.0.255 13 [langfang-ospf-100-area-0.0.0.0]network 172.16.1.4 0.0.0.0
"高碑店机房"配置如下：
1 [Huawei]sysname gaobeidian 2 [gaobeidian]interface LoopBack 1 3 [gaobeidian-LoopBack1]ip address 172.16.1.5 24 4 [gaobeidian-LoopBack1]quit 5 [gaobeidian]interface Ethernet 0/0/0 6 [gaobeidian-Ethernet0/0/0]ip address 192.168.1.5 24 7 [gaobeidian-Ethernet0/0/0]undo shutdown 8 [gaobeidian-Ethernet0/0/0]quit 9 [gaobeidian]router id 5.5.5.5 10 [gaobeidian]ospf 100 11 [gaobeidian-ospf-100]area 0 12 [gaobeidian-ospf-100-area-0.0.0.0]network 192.168.1.0 0.0.0.255 13 [gaobeidian-ospf-100-area-0.0.0.0]network 172.16.1.5 0.0.0.0
"双桥机房"配置如下：
1 [Huawei]sysname shuangqiao 2 [shuangqiao]interface LoopBack 1 3 [shuangqiao-LoopBack1]ip address 172.16.1.6 24 4 [shuangqiao-LoopBack1]quit 5 [shuangqiao]interface Ethernet 0/0/0 6 [shuangqiao-Ethernet0/0/0]ip address 192.168.1.6 24 7 [shuangqiao-Ethernet0/0/0]undo shutdown 8 [shuangqiao-Ethernet0/0/0]quit 9 [shuangqiao]interface Ethernet 0/0/0 10 [shuangqiao-Ethernet0/0/0]ospf dr-priority 50 11 [shuangqiao-Ethernet0/0/0]quit 12 [shuangqiao]router id 6.6.6.6 13 [shuangqiao]ospf 100 14 [shuangqiao-ospf-100]area 0 15 [shuangqiao-ospf-100-area-0.0.0.0]network 192.168.1.0 0.0.0.255 16 [shuangqiao-ospf-100-area-0.0.0.0]network 172.16.1.6 0.0.0.0
公司总部电脑测试结果如下:
1 PC>ipconfig 2 3 Link local IPv6 address...........: fe80::5689:98ff:fe86:12b 4 IPv6 address......................: :: / 128 5 IPv6 gateway......................: :: 6 IPv4 address......................: 172.30.1.3 7 Subnet mask.......................: 255.255.255.0 8 Gateway...........................: 172.30.1.254 9 Physical address..................: 54-89-98-86-01-2B 10 DNS server........................: 11 12 PC>ping 192.168.1.1 13 14 Ping 192.168.1.1: 32 data bytes, Press Ctrl_C to break 15 From 192.168.1.1: bytes=32 seq=1 ttl=254 time=32 ms 16 From 192.168.1.1: bytes=32 seq=2 ttl=254 time=46 ms 17 From 192.168.1.1: bytes=32 seq=3 ttl=254 time=47 ms 18 From 192.168.1.1: bytes=32 seq=4 ttl=254 time=31 ms 19 From 192.168.1.1: bytes=32 seq=5 ttl=254 time=47 ms 20 21 --- 192.168.1.1 ping statistics --- 22 5 packet(s) transmitted 23 5 packet(s) received 24 0.00% packet loss 25 round-trip min/avg/max = 31/40/47 ms 26 27 PC>ping 172.16.1.1 28 29 Ping 172.16.1.1: 32 data bytes, Press Ctrl_C to break 30 From 172.16.1.1: bytes=32 seq=1 ttl=254 time=47 ms 31 From 172.16.1.1: bytes=32 seq=2 ttl=254 time=63 ms 32 From 172.16.1.1: bytes=32 seq=3 ttl=254 time=78 ms 33 From 172.16.1.1: bytes=32 seq=4 ttl=254 time=47 ms 34 From 172.16.1.1: bytes=32 seq=5 ttl=254 time=47 ms 35 36 --- 172.16.1.1 ping statistics --- 37 5 packet(s) transmitted 38 5 packet(s) received 39 0.00% packet loss 40 round-trip min/avg/max = 47/56/78 ms 41 42 PC>ping 172.16.1.2 43 44 Ping 172.16.1.2: 32 data bytes, Press Ctrl_C to break 45 From 172.16.1.2: bytes=32 seq=1 ttl=254 time=63 ms 46 From 172.16.1.2: bytes=32 seq=2 ttl=254 time=62 ms 47 From 172.16.1.2: bytes=32 seq=3 ttl=254 time=47 ms 48 From 172.16.1.2: bytes=32 seq=4 ttl=254 time=47 ms 49 From 172.16.1.2: bytes=32 seq=5 ttl=254 time=63 ms 50 51 --- 172.16.1.2 ping statistics --- 52 5 packet(s) transmitted 53 5 packet(s) received 54 0.00% packet loss 55 round-trip min/avg/max = 47/56/63 ms 56 57 PC>ping 172.16.1.4 58 59 Ping 172.16.1.4: 32 data bytes, Press Ctrl_C to break 60 From 172.16.1.4: bytes=32 seq=1 ttl=254 time=93 ms 61 From 172.16.1.4: bytes=32 seq=2 ttl=254 time=46 ms 62 From 172.16.1.4: bytes=32 seq=3 ttl=254 time=62 ms 63 From 172.16.1.4: bytes=32 seq=4 ttl=254 time=46 ms 64 From 172.16.1.4: bytes=32 seq=5 ttl=254 time=47 ms 65 66 --- 172.16.1.4 ping statistics --- 67 5 packet(s) transmitted 68 5 packet(s) received 69 0.00% packet loss 70 round-trip min/avg/max = 46/58/93 ms 71 72 PC>ping 172.16.1.5 73 74 Ping 172.16.1.5: 32 data bytes, Press Ctrl_C to break 75 From 172.16.1.5: bytes=32 seq=1 ttl=254 time=94 ms 76 From 172.16.1.5: bytes=32 seq=2 ttl=254 time=47 ms 77 From 172.16.1.5: bytes=32 seq=3 ttl=254 time=47 ms 78 From 172.16.1.5: bytes=32 seq=4 ttl=254 time=47 ms 79 From 172.16.1.5: bytes=32 seq=5 ttl=254 time=47 ms 80 81 --- 172.16.1.5 ping statistics --- 82 5 packet(s) transmitted 83 5 packet(s) received 84 0.00% packet loss 85 round-trip min/avg/max = 47/56/94 ms 86 87 PC>
四.OSPF常用的调试命令
1.查看OSPF摘要信息
1 <qinghuayuan>display ospf brief 2 3 OSPF Process 100 with Router ID 3.3.3.3 4 OSPF Protocol Information 5 6 RouterID: 3.3.3.3 Border Router: 7 Multi-VPN-Instance is not enabled 8 Global DS-TE Mode: Non-Standard IETF Mode 9 Spf-schedule-interval: max 10000ms, start 500ms, hold 1000ms 10 Default ASE parameters: Metric: 1 Tag: 1 Type: 2 11 Route Preference: 10 12 ASE Route Preference: 150 13 SPF Computation Count: 7 14 RFC 1583 Compatible 15 Retransmission limitation is disabled 16 Area Count: 1 Nssa Area Count: 0 17 ExChange/Loading Neighbors: 0 18 19 Area: 0.0.0.0 (MPLS TE not enabled) 20 Authtype: None Area flag: Normal 21 SPF scheduled Count: 7 22 ExChange/Loading Neighbors: 0 23 Router ID conflict state: Normal 24 25 Interface: 172.30.1.254 (Ethernet0/0/1) 26 Cost: 1 State: DR Type: Broadcast MTU: 1500 27 Priority: 1 28 Designated Router: 172.30.1.254 29 Backup Designated Router: 0.0.0.0 30 Timers: Hello 10 , Dead 40 , Poll 120 , Retransmit 5 , Transmit Delay 1 31 32 Interface: 192.168.1.3 (Ethernet0/0/0) 33 Cost: 1 State: DROther Type: Broadcast MTU: 1500 34 Priority: 1 35 Designated Router: 192.168.1.1 36 Backup Designated Router: 192.168.1.2 37 Timers: Hello 10 , Dead 40 , Poll 120 , Retransmit 5 , Transmit Delay 1 38 <qinghuayuan>