封面图加载中

OSPF路由协议基础实验

本实验详细介绍了单区域 OSPF 的配置与原理。文章阐述了 OSPF 快速收敛、支持大规模网络、负载均衡和灵活扩展等核心优势，旨在帮助读者掌握 OSPF 的基本配置命令与认证方法。实验步骤涵盖 OSPF 进程创建、区域划分、接口使能及邻居状态查看，提供了实践 OSPF 路由协议的清晰指南。
  • 本文作者
  • 文章发布日期 2025-09-03 15:33
  • 热度 186
  • 天气 阴 17°~25°
  • 作者心情 有点不愉快
  • 地点 天作国际A座
  • 本文共计
  • 预计阅读

实验介绍

本实验将通过配置单区域OSPF，理解OSPF基本配置与原理。

OSPF的主要优点包括：

  • 快速收敛：OSPF能够迅速响应网络拓扑的变化，确保路由信息的及时更新，从而提高网络的稳定性和可靠性。

  • 支持大规模网络：OSPF可以有效地管理大型网络，支持分层设计，允许将网络划分为多个区域，以减少路由表的大小和复杂性。

  • 负载均衡：OSPF支持多条等价路径的负载均衡，能够在多个路径之间分配流量，提高网络的利用率。

  • 灵活性和扩展性：OSPF支持多种网络类型，包括点对点、广播和非广播多路访问（NBMA），使其适用于各种网络环境。

实验目的

掌握OSPF的基本配置命令与认证方法。

拓扑图

接口信息

参考IPv4编址及IPv4路由基础实验 - 晨星的设备名、物理接口和环回接口的IP地址配置。

路由器

接口

IP Address/Mask

R1

GigabitEthernet 2/0/3

10.0.13.1/24

GigabitEthernet 2/0/1

10.0.12.1/24

LoopBack0

10.0.1.1/32

R2

GigabitEthernet 2/0/1

10.0.12.2/24

GigabitEthernet 2/0/2

10.0.23.2/24

LoopBack0

10.0.1.2/32

R3

GigabitEthernet 2/0/3

10.0.13.3/24

GigabitEthernet 2/0/2

10.0.23.3/24

LoopBack0

10.0.1.3/32

实验步骤

基本配置

查看路由表

[R1]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
         Destinations : 10       Routes : 10

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

      10.0.12.0/24  Direct  0    0           D   10.0.12.1       GigabitEthernet2/0/1
      10.0.12.1/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/1
    10.0.12.255/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/1
      10.0.13.0/24  Direct  0    0           D   10.0.13.1       GigabitEthernet2/0/3
      10.0.13.1/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/3
    10.0.13.255/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/3
      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

OSPF基本配置

以R2为例，R1和R3同理。

[R2]ospf 1 router-id 10.0.1.2
[R2-ospf-1]area 0
[R2-ospf-1-area-0.0.0.0]network 10.0.12.2 0.0.0.0
[R2-ospf-1-area-0.0.0.0]network 10.0.23.2 0.0.0.0
[R2-ospf-1-area-0.0.0.0]network 10.0.1.2 0.0.0.0

创建OSPP进程

[R2]ospf 1 router-id 10.0.1.2

创建OSPF进程是设置与OSPF协议相关参数的第一步。OSPF可以同时运行多个进程，它们在同一设备上互不干扰，彼此独立。不同的OSPF进程之间的路由交换就像不同路由协议之间的交换一样。在创建OSPF进程时，可以指定一个进程编号，如果不指定，默认编号是「1」。

创建OSPF区域并使能相应的接口

[R2-ospf-1]area 0
[R2-ospf-1-area-0.0.0.0]network 10.0.12.2 0.0.0.0
[R2-ospf-1-area-0.0.0.0]network 10.0.23.2 0.0.0.0
[R2-ospf-1-area-0.0.0.0]network 10.0.1.2 0.0.0.0

network network-address wildcard-mask 用来指定在哪些接口上运行OSPF协议。只有满足以下两个条件，OSPF才能在接口上工作：

  1. 接口的IP地址掩码长度要大于或等于network命令中设置的掩码长度。例如，OSPF用的反掩码是0.0.0.255，表示掩码长度是24位。

  2. 接口的IP地址必须在network命令指定的网络范围内。

  3. 当使用network命令设置的通配符掩码为全0时，如果接口的IP地址和网络地址设置的IP地址一样，这个接口也会启用OSPF协议。

当这三个接口都启用后，它们都属于区域0。

OSPF报文交互过程实例：

May 13 2025 14:20:19-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[2]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=1.12.0.10, NeighborEvent=HelloReceived, NeighborPreviousState=Down, NeighborCurrentState=Init)
[R2-ospf-1-area-0.0.0.0]network 10.
May 13 2025 14:20:19-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[3]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=1.12.0.10, NeighborEvent=2WayReceived, NeighborPreviousState=Init, NeighborCurrentState=2Way)
[R2-ospf-1-area-0.0.0.0]network 10.
May 13 2025 14:20:19-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[4]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=1.12.0.10, NeighborEvent=AdjOk?, NeighborPreviousState=2Way, NeighborCurrentState=ExStart)
[R2-ospf-1-area-0.0.0.0]network 10.
May 13 2025 14:20:19-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[5]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=1.12.0.10, NeighborEvent=NegotiationDone, NeighborPreviousState=ExStart, NeighborCurrentState=Exchange)
[R2-ospf-1-area-0.0.0.0]network 10.
May 13 2025 14:20:19-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[6]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=1.12.0.10, NeighborEvent=ExchangeDone, NeighborPreviousState=Exchange, NeighborCurrentState=Loading)
[R2-ospf-1-area-0.0.0.0]network 10.
May 13 2025 14:20:19-08:00 R2 %%01OSPF/4/NBR_CHANGE_E(l)[7]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=1.12.0.10, NeighborEvent=LoadingDone, NeighborPreviousState=Loading, NeighborCurrentState=Full)

查看OSPF状态

查看OSPF邻居

[R1]display ospf peer

         OSPF Process 1 with Router ID 10.0.1.1
                 Neighbors

 Area 0.0.0.0 interface 10.0.12.1(GigabitEthernet2/0/1)'s neighbors
 Router ID: 10.0.1.2         Address: 10.0.12.2
   State: Full  Mode:Nbr is  Master  Priority: 1
   DR: 10.0.12.1  BDR: 10.0.12.2  MTU: 0
   Dead timer due in 29  sec
   Retrans timer interval: 5
   Neighbor is up for 00:09:12
   Authentication Sequence: [ 0 ]

                 Neighbors

 Area 0.0.0.0 interface 10.0.13.1(GigabitEthernet2/0/3)'s neighbors
 Router ID: 10.0.1.3         Address: 10.0.13.3
   State: Full  Mode:Nbr is  Master  Priority: 1
   DR: 10.0.13.1  BDR: 10.0.13.3  MTU: 0
   Dead timer due in 35  sec
   Retrans timer interval: 5
   Neighbor is up for 00:00:55
   Authentication Sequence: [ 0 ]

display ospf peer命令用来显示OSPF中各区域邻居的信息。包括邻居所属的区域、邻居Router ID、邻居状态、DR和BDR路由器等信息。

查看IP路由表中由OSPF学习到的路由

[R1]dis ip routing-table protocol ospf
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Public routing table : OSPF
         Destinations : 3        Routes : 4

OSPF routing table status : <Active>
         Destinations : 3        Routes : 4

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

       10.0.1.2/32  OSPF    10   1           D   10.0.12.2       GigabitEthernet2/0/1
       10.0.1.3/32  OSPF    10   1           D   10.0.13.3       GigabitEthernet2/0/3
      10.0.23.0/24  OSPF    10   2           D   10.0.12.2       GigabitEthernet2/0/1
                    OSPF    10   2           D   10.0.13.3       GigabitEthernet2/0/3

OSPF routing table status : <Inactive>
         Destinations : 0        Routes : 0

配置OSPF认证

在R1上配置接口认证

[R1]int g2/0/1
[R1-GigabitEthernet2/0/1]ospf authentication-mode md5 1 cipher HCIA-Datacom
[R1-GigabitEthernet2/0/1]int g2/0/3
[R1-GigabitEthernet2/0/3]ospf authentication-mode md5 1 cipher HCIA-Datacom
[R1-GigabitEthernet2/0/3]display this
[V200R003C00]
#
interface GigabitEthernet2/0/3
 ip address 10.0.13.1 255.255.255.0
 ospf authentication-mode md5 1 cipher %$%$omvj2GQBO-79%|52zX*T1GmU%$%$
#
return

由于cipher是密文口令类型，所以查看配置时以密文方式显示口令。

加密后OSFP服务down掉实例：

May 13 2025 14:57:20-08:00 R1 %%01OSPF/3/NBR_CHG_DOWN(l)[0]:Neighbor event:neighbor state changed to Down. (ProcessId=256, NeighborAddress=2.1.0.10, NeighborEvent=InactivityTimer, NeighborPreviousState=Full, NeighborCurrentState=Down)
[R1-GigabitEthernet2/0/3]ospf authentication-mode md5 1 cipher
May 13 2025 14:57:20-08:00 R1 %%01OSPF/3/NBR_DOWN_REASON(l)[1]:Neighbor state leaves full or changed to Down. (ProcessId=256, NeighborRouterId=2.1.0.10, NeighborAreaId=0, NeighborInterface=GigabitEthernet2/0/1,NeighborDownImmediate reason=Neighbor Down Due to Inactivity, NeighborDownPrimeReason=Hello Not Seen, NeighborChangeTime=2025-05-13 14:57:20-08:00)

查看当前邻居

[R1]dis ospf peer brief

         OSPF Process 1 with Router ID 10.0.1.1
                  Peer Statistic Information
 ----------------------------------------------------------------------------
 Area Id          Interface                        Neighbor id      State
 ----------------------------------------------------------------------------

认证不通过，故没有邻居。

配置R2上的接口认证

[R2]int g2/0/2
[R2-GigabitEthernet2/0/2]ospf authentication-mode md5 1 cipher HCIA-Datacom
[R2-GigabitEthernet2/0/2]int g2/0/1
[R2-GigabitEthernet2/0/1]ospf authentication-mode md5 1 cipher HCIA-Datacom

OSPF重新发送报文实例：

[R1]
May 13 2025 15:03:35-08:00 R1 %%01OSPF/4/NBR_CHANGE_E(l)[4]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=2.12.0.10, NeighborEvent=HelloReceived, NeighborPreviousState=Down, NeighborCurrentState=Init)
[R1]
May 13 2025 15:03:35-08:00 R1 %%01OSPF/4/NBR_CHANGE_E(l)[5]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=2.12.0.10, NeighborEvent=2WayReceived, NeighborPreviousState=Init, NeighborCurrentState=ExStart)
[R1]
May 13 2025 15:03:35-08:00 R1 %%01OSPF/4/NBR_CHANGE_E(l)[6]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=2.12.0.10, NeighborEvent=NegotiationDone, NeighborPreviousState=ExStart, NeighborCurrentState=Exchange)
[R1]
May 13 2025 15:03:35-08:00 R1 %%01OSPF/4/NBR_CHANGE_E(l)[7]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=2.12.0.10, NeighborEvent=ExchangeDone, NeighborPreviousState=Exchange, NeighborCurrentState=Loading)
[R1]
May 13 2025 15:03:35-08:00 R1 %%01OSPF/4/NBR_CHANGE_E(l)[8]:Neighbor changes event: neighbor status changed. (ProcessId=256, NeighborAddress=2.12.0.10, NeighborEvent=LoadingDone, NeighborPreviousState=Loading, NeighborCurrentState=Full)
[R1]

查看R2的邻居状态

[R2]display ospf peer brief

         OSPF Process 1 with Router ID 10.0.1.2
                  Peer Statistic Information
 ----------------------------------------------------------------------------
 Area Id          Interface                        Neighbor id      State
 0.0.0.0          GigabitEthernet2/0/1             10.0.1.1         Full
 ----------------------------------------------------------------------------
[R2]

R3同理。

配置完后，查看邻居状态。

[R3]dis ospf peer brief

         OSPF Process 1 with Router ID 10.0.1.3
                  Peer Statistic Information
 ----------------------------------------------------------------------------
 Area Id          Interface                        Neighbor id      State
 0.0.0.0          GigabitEthernet2/0/3             10.0.1.1         Full
 0.0.0.0          GigabitEthernet2/0/2             10.0.1.2         Full
 ----------------------------------------------------------------------------
[R3]

假设R2为所有网络的出口，所以在R2上向OSPF宣告默认路由

在R2上宣告默认路由

[R2]ospf
[R2-ospf-1]default-route-advertise always
[R2-ospf-1]

default-route-advertise命令用来将默认路由通告到普通OSPF区域，如果没有配置always参数，本机路由表中必须有激活的非本OSPF默认路由时才向其他路由器发布默认路由。本例中，本地路由表中没有默认路由，所以需要增加always参数。

查看R3上的路由表

[R3]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
         Destinations : 15       Routes : 16

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

        0.0.0.0/0   O_ASE   150  1           D   10.0.23.2       GigabitEthernet2/0/2
       10.0.1.1/32  OSPF    10   1           D   10.0.13.1       GigabitEthernet2/0/3
       10.0.1.2/32  OSPF    10   1           D   10.0.23.2       GigabitEthernet2/0/2
       10.0.1.3/32  Direct  0    0           D   127.0.0.1       LoopBack0
      10.0.12.0/24  OSPF    10   2           D   10.0.23.2       GigabitEthernet2/0/2
                    OSPF    10   2           D   10.0.13.1       GigabitEthernet2/0/3
      10.0.13.0/24  Direct  0    0           D   10.0.13.3       GigabitEthernet2/0/3
      10.0.13.3/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/3
    10.0.13.255/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/3
      10.0.23.0/24  Direct  0    0           D   10.0.23.3       GigabitEthernet2/0/2
      10.0.23.3/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/2
    10.0.23.255/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/2
      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

[R3]

可知，R3已经学习到了相应的默认路由。

通过开销值控制选路

从R1的路由表可知，R1通过R1->R3的路径访问R3的LoopBack0接口的路由开销为1，从R1->R2->R3的路由开销为2，故只要使R1->R3的路由开销大于2即可。

修改开销值

[R1]int g2/0/3
[R1-GigabitEthernet2/0/3]ospf cost 10
[R1-GigabitEthernet2/0/3]

查看路由表

[R1]dis ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
         Destinations : 15       Routes : 15

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

        0.0.0.0/0   O_ASE   150  1           D   10.0.12.2       GigabitEthernet2/0/1
       10.0.1.1/32  Direct  0    0           D   127.0.0.1       LoopBack0
       10.0.1.2/32  OSPF    10   1           D   10.0.12.2       GigabitEthernet2/0/1
       10.0.1.3/32  OSPF    10   2           D   10.0.12.2       GigabitEthernet2/0/1
      10.0.12.0/24  Direct  0    0           D   10.0.12.1       GigabitEthernet2/0/1
      10.0.12.1/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/1
    10.0.12.255/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/1
      10.0.13.0/24  Direct  0    0           D   10.0.13.1       GigabitEthernet2/0/3
      10.0.13.1/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/3
    10.0.13.255/32  Direct  0    0           D   127.0.0.1       GigabitEthernet2/0/3
      10.0.23.0/24  OSPF    10   2           D   10.0.12.2       GigabitEthernet2/0/1
      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

[R1]

比时R1访问R3的LoopBack0接口的下一跳为R2的GigabitEthernet2/0/1接口。

通过Tracert命令验证

[R1]tracert -a 10.0.1.1 10.0.1.3
 traceroute to  10.0.1.3(10.0.1.3), max hops: 30 ,packet length: 40,press CTRL_C to break
 1 10.0.12.2 30 ms  20 ms  20 ms
 2 10.0.23.3 40 ms  10 ms  10 ms
[R1]