文章目录
一：OSPF路由协议概述
1.1 内部网关协议和外部网关协议
- 自治系统（AS）
- 内部网关协议（IGP）
- 外部网关协议（EGP）
1.2 OSPF是链路状态路由协议
将自己的直连链路状态，发送给别的路由
二：OSPF的工作过程
- 邻居列表
- 链路状态数据库
- 路由表
三：OSPF的基本概念
3.1 OSPF区域
- 为了适应大型的网络，OSPF在AS内划分多个区域
- 每个OSPF路由器只维护所在区域的完整链路状态信息
3.2 区域ID
- 区域id可以表示成一个十进制的数字
- 也可以表示成一个ip
3.3 骨干区域Area 0
- 负责区域间路由信息转播
3.4 非骨干区域
3.5 Router ID
- OSPF区域内唯一标识路由器的IP地址
3.6 Router ID 选举规则
- 选举路由器lookback接口上数值最高的IP地址
- 如果没有lookback接口，在物理端口中选取IP地址最高的
- 也可以使用router-id 命令指定Router ID
3.7 DR和BDR
3.8 指定路由器（DR）
3.9 其他路由器（DRothers）只和DR及BDR形成邻接关系
3.10 DR和BDR的选举方法
- 自动选举DR和BDR
- 网段上Router ID最大的路由器将被选举为DR，第二大的将被选举为DBR
- 手工选择DR和BDR
- 优先级范围是0-255，数值越大，优先级越高，默认为1
- 如果优先级相同，则需要比较Router ID
- 如果路由器的优先级被设置为0，它将不参与DR和DBR的选举
3.11 DR和BDR的选举过程
- 路由器的优先级可以影响一个选举过程，但是它不能强制更换已经存在的DR或BDR路由器
- OSPF的组播地址
- 224.0.0.5 DR通过224.0.0.5向所有邻居通告信息
- 224.0.0.6 Rrother通过224.0.0.6向DR和BDR通告网络状态信息
3.12 OSPF的度量值为COST
3.13 ospf的协议号为89
四：OSPF的数据包类型
v3是支持ipv6的
五：实验验证：
配置完ip地址后，开始抓包
AR1
The device is running!
<Huawei>system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]un in en
Info: Information center is disabled.
[Huawei]sysname AR1
[AR1]int LoopBack 0
[AR1-LoopBack0]ip add 1.1.1.1 32
[AR1-LoopBack0]int g 0/0/0
[AR1-GigabitEthernet0/0/0]ip add 12.0.0.1 30
[AR1-GigabitEthernet0/0/0]un sh
Info: Interface GigabitEthernet0/0/0 is not shutdown.
[AR1-GigabitEthernet0/0/0]q
[AR1]ospf 1 router-id 1.1.1.1
[AR1-ospf-1]area 0
[AR1-ospf-1-area-0.0.0.0]network 12.0.0.0 0.0.0.3
[AR1-ospf-1-area-0.0.0.0]network 1.1.1.1 0.0.0.0
[AR1-ospf-1-area-0.0.0.0]
AR2
The device is running!
<Huawei>system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]un in en
Info: Information center is disabled.
[Huawei]sysname AR2
[AR2]int LoopBack 0
[AR2-LoopBack0]ip add 2.2.2.2 32
[AR2-LoopBack0]int g 0/0/0
[AR2-GigabitEthernet0/0/0]ip add 12.0.0.2 30
[AR2-GigabitEthernet0/0/0]un sh
Info: Interface GigabitEthernet0/0/0 is not shutdown.
[AR2-GigabitEthernet0/0/0]int g 0/0/1
[AR2-GigabitEthernet0/0/1]ip add 23.0.0.1 30
[AR2-GigabitEthernet0/0/1]un sh
Info: Interface GigabitEthernet0/0/1 is not shutdown.
[AR2-GigabitEthernet0/0/1]q
[AR2]ospf 1 router-id 2.2.2.2
[AR2-ospf-1]area 0
[AR2-ospf-1-area-0.0.0.0]network 12.0.0.0 0.0.0.3
[AR2-ospf-1-area-0.0.0.0]ne
[AR2-ospf-1-area-0.0.0.0]network 23.0.0.0 0.0.0.3
[AR2-ospf-1-area-0.0.0.0]network 2.2.2.2 0.0.0.0
AR3
The device is running!
<Huawei>system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]un in en
Info: Information center is disabled.
[Huawei]sysname AR3
[AR3]int LoopBack 0
[AR3-LoopBack0]ip add 3.3.3.3 32
[AR3-LoopBack0]int g 0/0/1
[AR3-GigabitEthernet0/0/1]ip add 23.0.0.2 30
[AR3-GigabitEthernet0/0/1]un sh
Info: Interface GigabitEthernet0/0/1 is not shutdown.
[AR3-GigabitEthernet0/0/1]int g 0/0/0
[AR3-GigabitEthernet0/0/0]ip add 35.0.0.1 24
[AR3-GigabitEthernet0/0/0]un sh
Info: Interface GigabitEthernet0/0/0 is not shutdown.
[AR3-GigabitEthernet0/0/0]q
[AR3]ospf 1 router-id 3.3.3.3
[AR3-ospf-1]area 0
[AR3-ospf-1-area-0.0.0.0]network 23.0.0.0 0.0.0.3
[AR3-ospf-1-area-0.0.0.0]network 3.3.3.3 0.0.0.0
[AR3-ospf-1-area-0.0.0.0]network 35.0.0.0 0.0.0.255
AR4
The device is running!
<Huawei>system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname AR4
[AR4]un in en
Info: Information center is disabled.
[AR4]int loo 0
[AR4-LoopBack0]ip add 4.4.4.4 32
[AR4-LoopBack0]int g 0/0/0
[AR4-GigabitEthernet0/0/0]ip add 35.0.0.2 24
[AR4-GigabitEthernet0/0/0]un sh
Info: Interface GigabitEthernet0/0/0 is not shutdown.
[AR4-GigabitEthernet0/0/0]q
[AR4]ospf 1 router-id 4.4.4.4
[AR4-ospf-1]area 0
[AR4-ospf-1-area-0.0.0.0]network 4.4.4.4 0.0.0.0
[AR4-ospf-1-area-0.0.0.0]network 35.0.0.0 0.0.0.255
[AR4-ospf-1-area-0.0.0.0]q
AR5
The device is running!
<Huawei>system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]un in en
Info: Information center is disabled.
[Huawei]sysname AR5
[AR5]int loo 0
[AR5-LoopBack0]ip add 5.5.5.5 32
[AR5-LoopBack0]int g 0/0/0
[AR5-GigabitEthernet0/0/0]ip add 35.0.0.3 24
[AR5-GigabitEthernet0/0/0]un sh
Info: Interface GigabitEthernet0/0/0 is not shutdown.
[AR5-GigabitEthernet0/0/0]q
[AR5]ospf 1 router-id 5.5.5.5
[AR5-ospf-1]area 0
[AR5-ospf-1-area-0.0.0.0]network 35.0.0.0 0.0.0.255
[AR5-ospf-1-area-0.0.0.0]network 5.5.5.5 0.0.0.0
查看路由表
AR1：
[AR1]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
Destinations : 14 Routes : 14
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0
2.2.2.2/32 OSPF 10 1 D 12.0.0.2 GigabitEthernet
0/0/0
3.3.3.3/32 OSPF 10 2 D 12.0.0.2 GigabitEthernet
0/0/0
4.4.4.4/32 OSPF 10 3 D 12.0.0.2 GigabitEthernet
0/0/0
5.5.5.5/32 OSPF 10 3 D 12.0.0.2 GigabitEthernet
0/0/0
12.0.0.0/30 Direct 0 0 D 12.0.0.1 GigabitEthernet
0/0/0
12.0.0.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
12.0.0.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
23.0.0.0/30 OSPF 10 2 D 12.0.0.2 GigabitEthernet
0/0/0
35.0.0.0/24 OSPF 10 3 D 12.0.0.2 GigabitEthernet
0/0/0
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
AR2：
[AR2]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
Destinations : 16 Routes : 16
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 OSPF 10 1 D 12.0.0.1 GigabitEthernet
0/0/0
2.2.2.2/32 Direct 0 0 D 127.0.0.1 LoopBack0
3.3.3.3/32 OSPF 10 1 D 23.0.0.2 GigabitEthernet
0/0/1
4.4.4.4/32 OSPF 10 2 D 23.0.0.2 GigabitEthernet
0/0/1
5.5.5.5/32 OSPF 10 2 D 23.0.0.2 GigabitEthernet
0/0/1
12.0.0.0/30 Direct 0 0 D 12.0.0.2 GigabitEthernet
0/0/0
12.0.0.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
12.0.0.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
23.0.0.0/30 Direct 0 0 D 23.0.0.1 GigabitEthernet
0/0/1
23.0.0.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/1
23.0.0.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/1
35.0.0.0/24 OSPF 10 2 D 23.0.0.2 GigabitEthernet
0/0/1
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
AR3：
[AR3]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
Destinations : 16 Routes : 16
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 OSPF 10 2 D 23.0.0.1 GigabitEthernet
0/0/1
2.2.2.2/32 OSPF 10 1 D 23.0.0.1 GigabitEthernet
0/0/1
3.3.3.3/32 Direct 0 0 D 127.0.0.1 LoopBack0
4.4.4.4/32 OSPF 10 1 D 35.0.0.2 GigabitEthernet
0/0/0
5.5.5.5/32 OSPF 10 1 D 35.0.0.3 GigabitEthernet
0/0/0
12.0.0.0/30 OSPF 10 2 D 23.0.0.1 GigabitEthernet
0/0/1
23.0.0.0/30 Direct 0 0 D 23.0.0.2 GigabitEthernet
0/0/1
23.0.0.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/1
23.0.0.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/1
35.0.0.0/24 Direct 0 0 D 35.0.0.1 GigabitEthernet
0/0/0
35.0.0.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
35.0.0.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
AR4：
[AR4]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
Destinations : 14 Routes : 14
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 OSPF 10 3 D 35.0.0.1 GigabitEthernet
0/0/0
2.2.2.2/32 OSPF 10 2 D 35.0.0.1 GigabitEthernet
0/0/0
3.3.3.3/32 OSPF 10 1 D 35.0.0.1 GigabitEthernet
0/0/0
4.4.4.4/32 Direct 0 0 D 127.0.0.1 LoopBack0
5.5.5.5/32 OSPF 10 1 D 35.0.0.3 GigabitEthernet
0/0/0
12.0.0.0/30 OSPF 10 3 D 35.0.0.1 GigabitEthernet
0/0/0
23.0.0.0/30 OSPF 10 2 D 35.0.0.1 GigabitEthernet
0/0/0
35.0.0.0/24 Direct 0 0 D 35.0.0.2 GigabitEthernet
0/0/0
35.0.0.2/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
35.0.0.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
AR5：
[AR5]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
Destinations : 14 Routes : 14
Destination/Mask Proto Pre Cost Flags NextHop Interface
1.1.1.1/32 OSPF 10 3 D 35.0.0.1 GigabitEthernet
0/0/0
2.2.2.2/32 OSPF 10 2 D 35.0.0.1 GigabitEthernet
0/0/0
3.3.3.3/32 OSPF 10 1 D 35.0.0.1 GigabitEthernet
0/0/0
4.4.4.4/32 OSPF 10 1 D 35.0.0.2 GigabitEthernet
0/0/0
5.5.5.5/32 Direct 0 0 D 127.0.0.1 LoopBack0
12.0.0.0/30 OSPF 10 3 D 35.0.0.1 GigabitEthernet
0/0/0
23.0.0.0/30 OSPF 10 2 D 35.0.0.1 GigabitEthernet
0/0/0
35.0.0.0/24 Direct 0 0 D 35.0.0.3 GigabitEthernet
0/0/0
35.0.0.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
35.0.0.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
D 127.0.0.1 GigabitEthernet
0/0/0
35.0.0.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet
0/0/0
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
