课题内容：
OSPF路由汇总研究
在R5上配置4个末节网络，通告进OSPF区域1，在R3上做汇总为一条路由
观察汇总后的情况：产生指向的null 0的路由、汇总路由的度量值、LSA
在R2上配置四个末节网络，重分布进OSPF区域2，在R2上做汇总
观察汇总后的情况：产生指向的null 0的路由、汇总路由的度量值、LSA
拓扑图
步骤：
一、进行基本部署
1、 配置IP地址 配置省略 （含帧中继配置）
R2：
default int s1/0
default int s1/1
default int s1/2
frame-relay switching
interface Serial1/0
no ip address
no shut
encapsulation frame-relay
frame-relay intf-type dce
frame-relay route 103 interface Serial1/2 301
frame-relay route 104 interface Serial1/1 401 //本实验中，没有这条配置 //
!
interface Serial1/1
no ip address
no shut
encapsulation frame-relay
frame-relay intf-type dce
frame-relay route 401 interface Serial1/0 104 //本实验中，没有这条配置 //
frame-relay route 403 interface Serial1/2 304
!
interface Serial1/2
no ip address
no shut
encapsulation frame-relay
frame-relay intf-type dce
frame-relay route 301 interface Serial1/0 103
frame-relay route 304 interface Serial1/1 403
R1:
interface Serial1/0
no shutdown
ip address 10.1.1.1 255.255.255.0
encapsulation frame-relay
R3：
interface Serial1/2
no shutdown
ip address 10.1.1.3 255.255.255.0
encapsulation frame-relay
R4：
interface Serial1/1
no shutdown
ip address 10.1.1.4 255.255.255.0
encapsulation frame-relay
每台设备配置环回口，做为router-id
规划为： 172.16.1.X/32中 X = 设备编号
例如： R1的环回口地址为 172.16.1.1/32
2、 配置OSPF协议 （配置省略）
需要特殊注意，R1、R3、R4通过帧中继网络互联，其中R1和R4之间没有虚电路，无法直接通信，在这里推荐采用OSPF的点到多点网络工作模式；
检查OSPF邻居：
R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
172.16.1.1 0 FULL/ - 00:01:49 10.1.1.1 Serial1/2
172.16.1.4 0 FULL/ - 00:01:56 10.1.1.4 Serial1/2
172.16.1.5 0 FULL/ - 00:00:32 10.1.35.5 Ethernet0/3
R2#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
172.16.1.1 1 FULL/DROTHER 00:00:32 10.1.124.1 Ethernet0/2
172.16.1.4 1 FULL/DR 00:00:38 10.1.124.4 Ethernet0/2
3、 在R5上配置4个末节网络，通告进OSPF区域1，在R3上做汇总为一条路由
规划四个末节网络IP网络号分别为： 192.168.5.0/30 配置四个连续的子网；
R5
interface Loopback0
ip address 192.168.5.1 255.255.255.252 secondary
ip address 192.168.5.5 255.255.255.252 secondary
ip address 192.168.5.9 255.255.255.252 secondary
ip address 192.168.5.13 255.255.255.252 secondary
ip address 172.16.1.5 255.255.255.255
ip ospf 110 area 1
在R3上做汇总为一条路由
R3(config)#router ospf 110
R3(config-router)#area 1 range 192.168.5.0 255.255.255.240
观察汇总后的情况：产生指向的null 0的路由、汇总路由的度量值、LSA
R3#show ip route ospf | in summary
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
O 192.168.5.0/28 is a summary, 00:01:30, Null0
//在R3本地形成了一条指向null 0 的汇总路由
R3#show ip ospf database summary 192.168.5.0 self-originate
OSPF Router with ID (172.16.1.3) (Process ID 110)
Summary Net Link States (Area 0)
LS age: 159
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 192.168.5.0 (summary Network Number)
Advertising Router: 172.16.1.3
LS Seq Number: 80000002
Checksum: 0x70A
Length: 28
Network Mask: /28
MTID: 0 Metric: 11
在R2上配置四个末节网络
规划为： 10.2.X.0/24
ip address 10.2.1.1 255.255.255.0 secondary
ip address 10.2.2.1 255.255.255.0 secondary
ip address 10.2.3.1 255.255.255.0 secondary
ip address 10.2.0.1 255.255.255.0
重分布进OSPF区域2
R2(config)#router ospf 110
R2(config-router)#redistribute connected subnets
验证：
R2#show ip ospf database | begin Type-5
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
10.2.0.0 172.16.1.2 49 0x80000001 0x00A72D 0
10.2.1.0 172.16.1.2 49 0x80000001 0x009C37 0
10.2.2.0 172.16.1.2 49 0x80000001 0x009141 0
10.2.3.0 172.16.1.2 49 0x80000001 0x00864B 0
R5#show ip route ospf | include O E
O E2 10.2.0.0/24 [110/20] via 10.1.35.3, 00:01:29, Ethernet0/3
O E2 10.2.1.0/24 [110/20] via 10.1.35.3, 00:01:29, Ethernet0/3
O E2 10.2.2.0/24 [110/20] via 10.1.35.3, 00:01:29, Ethernet0/3
O E2 10.2.3.0/24 [110/20] via 10.1.35.3, 00:01:29, Ethernet0/3
在R2上做汇总
R2(config-router)#summary-address 10.2.0.0 255.255.252.0
验证：
R2#show ip ospf database | begin Type-5
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
10.2.0.0 172.16.1.2 32 0x80000003 0x009441 0
R5#show ip route ospf | include O E
O E2 10.2.0.0/22 [110/20] via 10.1.35.3, 00:00:43, Ethernet0/3
观察汇总后的情况：产生指向的null 0的路由、汇总路由的度量值、LSA
R2#show ip route ospf | include summary
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
l 10.2.0.0/22 is a summary, 00:01:28, Null0
R2#show ip ospf database external self-originate
OSPF Router with ID (172.16.1.2) (Process ID 110)
Type-5 AS External Link States
LS age: 112
Options: (No TOS-capability, DC, Upward)
LS Type: AS External Link
Link State ID: 10.2.0.0 (External Network Number )
Advertising Router: 172.16.1.2
LS Seq Number: 80000003
Checksum: 0x9441
Length: 36
Network Mask: /22
Metric Type: 2 (Larger than any link state path)
MTID: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0
谢谢大家！
我是乾颐堂CCIE导师，CCIE培训金牌讲师达叔。
本博客由乾颐堂达叔独家冠名写出，素材来自乾颐堂日常工作及达叔和他身边的CCIE们的故事。