拓扑结构
实现功能
- 设备IP地址配置。
- 按照规划配置OSPF区域。
- 检查OSPF配置结果，检查OSPF邻居关系状态，在ABR上查看OSPF LSDB。
- 在ABR、ASBR上配置路由汇总，减少区域间、外部路由数量。
- 修改OSPF的参考带宽值。
- 在OSPF中引入缺省路由。
- 修改OSPF域内、域间路由和域外路由的缺省路由优先级。
步骤
1. 基础配置
以R3为例：
#
sysname R3
#
interface LoopBack0
ip address 10.3.3.3 255.255.255.255
#
interface LoopBack1
ip address 10.3.0.1 255.255.255.0
#
interface LoopBack2
ip address 10.3.1.1 255.255.255.0
#
interface GigabitEthernet0/0/0
ip address 10.0.123.3 255.255.255.0
[R3]display ip interface brief
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
The number of interface that is UP in Physical is 5
The number of interface that is DOWN in Physical is 2
The number of interface that is UP in Protocol is 5
The number of interface that is DOWN in Protocol is 2
Interface IP Address/Mask Physical Protocol
GigabitEthernet0/0/0 10.0.123.3/24 up up
GigabitEthernet0/0/1 unassigned down down
GigabitEthernet0/0/2 unassigned down down
LoopBack0 10.3.3.3/32 up up(s)
LoopBack1 10.3.0.1/24 up up(s)
LoopBack2 10.3.1.1/24 up up(s)
NULL0 unassigned up up(s) 2. 配置多区域OSPF
以R2配置为例；
-
在R2与R4互联接口上修改网络类型为P2P，加快邻接关系建立；
ospf 1 router-id 10.2.2.2
area 0.0.0.0
network 10.0.24.1 0.0.0.0
network 10.2.2.2 0.0.0.0
area 0.0.0.2
network 10.0.123.2 0.0.0.0interface GigabitEthernet0/0/1
ip address 10.0.24.1 255.255.255.252
ospf network-type p2p
配置完成后R2和R4上的邻居关系
<R2>display ospf peer brief
OSPF Process 1 with Router ID 10.2.2.2
Peer Statistic Information
----------------------------------------------------------------------------
Area Id Interface Neighbor id State
0.0.0.0 GigabitEthernet0/0/1 10.4.4.4 Full
0.0.0.2 GigabitEthernet0/0/0 10.1.1.1 Full
0.0.0.2 GigabitEthernet0/0/0 10.3.3.3 Full
----------------------------------------------------------------------------
<R4>display ospf peer brief
OSPF Process 1 with Router ID 10.4.4.4
Peer Statistic Information
----------------------------------------------------------------------------
Area Id Interface Neighbor id State
0.0.0.0 GigabitEthernet0/0/0 10.2.2.2 Full
0.0.0.1 GigabitEthernet0/0/1 10.5.5.5 Full
---------------------------------------------------------------------------- 配置完成后R2和R4上的LSDB
R2和R4作为ABR维护两个区域的LSDB
<R2>display ospf lsdb
OSPF Process 1 with Router ID 10.2.2.2
Link State Database
Area: 0.0.0.0
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 10.2.2.2 10.2.2.2 1582 60 8000000C 0
Router 10.4.4.4 10.4.4.4 1583 60 8000000C 0
Sum-Net 10.3.1.0 10.2.2.2 220 28 80000001 1
Sum-Net 10.3.0.0 10.2.2.2 226 28 80000001 1
Sum-Net 10.5.1.0 10.4.4.4 137 28 80000001 1
Sum-Net 10.5.0.0 10.4.4.4 147 28 80000001 1
Sum-Net 10.5.5.5 10.4.4.4 1461 28 80000001 1
Sum-Net 10.1.1.1 10.2.2.2 1362 28 80000001 1
Sum-Net 10.0.45.0 10.4.4.4 1629 28 80000001 1
Sum-Net 10.0.123.0 10.2.2.2 1733 28 80000001 1
Sum-Net 10.3.3.3 10.2.2.2 1296 28 80000001 1
Area: 0.0.0.2
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 10.3.3.3 10.3.3.3 182 72 8000000E 0
Router 10.2.2.2 10.2.2.2 668 60 8000000F 1
Router 10.1.1.1 10.1.1.1 1303 48 80000006 0
Network 10.0.123.2 10.2.2.2 1296 36 80000004 0
Sum-Net 10.0.24.0 10.2.2.2 1714 28 80000001 1
Sum-Net 10.5.1.0 10.2.2.2 136 28 80000001 2
Sum-Net 10.5.0.0 10.2.2.2 146 28 80000001 2
Sum-Net 10.4.4.4 10.2.2.2 1582 28 80000001 1
Sum-Net 10.5.5.5 10.2.2.2 1460 28 80000001 2
Sum-Net 10.0.45.0 10.2.2.2 1582 28 80000001 2
Sum-Net 10.2.2.2 10.2.2.2 1733 28 80000001 0
<R4>display ospf lsdb
OSPF Process 1 with Router ID 10.4.4.4
Link State Database
Area: 0.0.0.0
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 10.2.2.2 10.2.2.2 1626 60 8000000C 0
Router 10.4.4.4 10.4.4.4 1625 60 8000000C 0
Sum-Net 10.3.1.0 10.2.2.2 264 28 80000001 1
Sum-Net 10.3.0.0 10.2.2.2 270 28 80000001 1
Sum-Net 10.5.1.0 10.4.4.4 178 28 80000001 1
Sum-Net 10.5.0.0 10.4.4.4 189 28 80000001 1
Sum-Net 10.5.5.5 10.4.4.4 1502 28 80000001 1
Sum-Net 10.1.1.1 10.2.2.2 1406 28 80000001 1
Sum-Net 10.0.45.0 10.4.4.4 1671 28 80000001 1
Sum-Net 10.0.123.0 10.2.2.2 1777 28 80000001 1
Sum-Net 10.3.3.3 10.2.2.2 1339 28 80000001 1
Area: 0.0.0.1
Type LinkState ID AdvRouter Age Len Sequence Metric
Router 10.5.5.5 10.5.5.5 136 72 80000008 0
Router 10.4.4.4 10.4.4.4 1500 36 80000005 1
Network 10.0.45.1 10.4.4.4 1500 32 80000002 0
Sum-Net 10.3.1.0 10.4.4.4 263 28 80000001 2
Sum-Net 10.3.0.0 10.4.4.4 269 28 80000001 2
Sum-Net 10.0.24.0 10.4.4.4 1671 28 80000001 1
Sum-Net 10.4.4.4 10.4.4.4 1671 28 80000001 0
Sum-Net 10.1.1.1 10.4.4.4 1405 28 80000001 2
Sum-Net 10.2.0.0 10.4.4.4 757 28 80000001 1
Sum-Net 10.0.123.0 10.4.4.4 1624 28 80000001 2
Sum-Net 10.3.3.3 10.4.4.4 1339 28 80000001 2 3. 配置路由汇总
3.1 区域间路由汇总
区域间路由汇总减少区域间的路由条目，也减少了路由震荡的发生。
在R4区域1（要汇总那个区域的路由就在那个区域执行汇总）对R5的L1和L2的路由进行汇聚。
sw
#
ospf 1 router-id 10.4.4.4
area 0.0.0.0
network 10.0.24.2 0.0.0.0
network 10.4.4.4 0.0.0.0
area 0.0.0.1
abr-summary 10.5.0.0 255.255.254.0
network 10.0.45.1 0.0.0.0 汇总后，R4作为ABR再向区域0发布路由时只发布汇总后的路由
[R4-ospf-1]display ospf lsdb
OSPF Process 1 with Router ID 10.4.4.4
Link State Database
Area: 0.0.0.0
Type LinkState ID AdvRouter Age Len Sequence Metric
Sum-Net 10.5.0.0 10.4.4.4 92 28 80000002 1
Sum-Net 10.5.5.5 10.4.4.4 22 28 80000002 1 在R2上区域2中对R3的L1和L2接口路由进行汇总
ospf 1 router-id 10.2.2.2
area 0.0.0.0
network 10.0.24.1 0.0.0.0
network 10.2.2.2 0.0.0.0
area 0.0.0.2
abr-summary 10.2.0.0 255.255.254.0
network 10.0.123.2 0.0.0.0 汇总后R2在向区域0发布汇总后的路由
[R2]display ospf lsdb
OSPF Process 1 with Router ID 10.2.2.2
Link State Database
Area: 0.0.0.0
Type LinkState ID AdvRouter Age Len Sequence Metric
Sum-Net 10.3.0.0 10.2.2.2 1226 28 80000001 1 3.2 区域外路由汇总
在R2上将L1和L2的路由引入到OSPF（为了避免引入其他直连路由影响观察，这里做了ip前缀过滤）
ospf 1 router-id 10.2.2.2
filter-policy ip-prefix 1 export
import-route direct
area 0.0.0.0
network 10.0.24.1 0.0.0.0
network 10.2.2.2 0.0.0.0
area 0.0.0.2
abr-summary 10.2.0.0 255.255.254.0
network 10.0.123.2 0.0.0.0
#
ip ip-prefix 1 index 10 permit 10.2.0.0 24
ip ip-prefix 1 index 20 permit 10.2.1.0 24 引入后R4收到2条5类LSA
R5收到5类LSA和R4通告的4类LSA
在R2上进行外部路由汇聚
ospf 1 router-id 10.2.2.2
asbr-summary 10.2.0.0 255.255.254.0
filter-policy ip-prefix 1 export
import-route direct
area 0.0.0.0
network 10.0.24.1 0.0.0.0
network 10.2.2.2 0.0.0.0
area 0.0.0.2
abr-summary 10.2.0.0 255.255.254.0
network 10.0.123.2 0.0.0.0 R5此时的OSPF路由表和IP路由表
4、修改OSPF参考带宽值
以R2为例
!WARNING
OSPF域内的所有路由器参考贷款值必须一致
ospf 1 router-id 10.2.2.2
bandwidth-reference 10000 
5、在OSPF引入缺省路由
在R1的L0接口模拟接入互联网
]ip route-static 0.0.0.0 0.0.0.0 LoopBack 0 将缺省路由引入到OSPF，指定外部类型为Type 1
ospf 1 router-id 10.1.1.1
default-route-advertise always type 1!IMPORTANT
default-route-advertise always type 1
- always 无论本机是否存在激活的非本OSPF进程缺省路由，都会产生并发布一个描述缺省路由的LSA。
- type 指定外部路由类型（缺省为2）
在其他路由器查看引入的默认路由，以R2为例，因为引入Type=1，因此会计算Cost
6、修改OSPF中路由优先级
以R3为例，修改OSPF协议区域内、区域间的路由优先级为20，修改外部路由优先级为50
ospf 1 router-id 10.3.3.3
preference 20
preference ase 50 
完整配置
R2为例
<R2>display current-configuration
[V200R003C00]
#
sysname R2
#
snmp-agent local-engineid 800007DB03000000000000
snmp-agent
#
clock timezone China-Standard-Time minus 08:00:00
#
portal local-server load portalpage.zip
#
drop illegal-mac alarm
#
router id 10.2.2.2
#
set cpu-usage threshold 80 restore 75
#
aaa
authentication-scheme default
authorization-scheme default
accounting-scheme default
domain default
domain default_admin
local-user admin password cipher %$%$K8m.Nt84DZ}e#<0`8bmE3Uw}%$%$
local-user admin service-type http
#
firewall zone Local
priority 15
#
interface GigabitEthernet0/0/0
ip address 10.0.123.2 255.255.255.0
#
interface GigabitEthernet0/0/1
ip address 10.0.24.1 255.255.255.252
ospf network-type p2p
#
interface GigabitEthernet0/0/2
#
interface NULL0
#
interface LoopBack0
ip address 10.2.2.2 255.255.255.255
#
interface LoopBack1
ip address 10.2.0.1 255.255.255.0
#
interface LoopBack2
ip address 10.2.1.1 255.255.255.0
#
ospf 1 router-id 10.2.2.2
asbr-summary 10.2.0.0 255.255.254.0
filter-policy ip-prefix 1 export
import-route direct
bandwidth-reference 10000
area 0.0.0.0
network 10.0.24.1 0.0.0.0
network 10.2.2.2 0.0.0.0
area 0.0.0.2
abr-summary 10.2.0.0 255.255.254.0
network 10.0.123.2 0.0.0.0
#
ip ip-prefix 1 index 10 permit 10.2.0.0 24
ip ip-prefix 1 index 20 permit 10.2.1.0 24
#
user-interface con 0
authentication-mode password
user-interface vty 0 4
user-interface vty 16 20
#
wlan ac
#
return 延伸
外部路由的两种类型
Type-1 可信度高，开销计算= AS外部开销 + AS内部开销
Type-2 可信度低，AS外部开销远大于内部开销，开销值计算= AS外部开销