stub&totally sutb
OSPF Stub area & Totally stub
一、 实验目的
1、 stub和totally stub区域存在的条件。
2、 它们会对哪几类LSA进行过滤。
3、 它们存在的好处
二、 实验拓扑
三、 Stub区域实验
首先将RIP重发布到area 2 内。查看R1的路由表和OSPF 数据库。
R1(config-router)#do show ip rout
Gateway of last resort is not set
34.0.0.0/24 is subnetted, 1 subnets
O IA 34.1.1.0 [110/192] via 12.1.1.2, 00:09:33, Serial0/0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O IA 2.2.2.2 [110/65] via 12.1.1.2, 00:09:33, Serial0/0
3.0.0.0/32 is subnetted, 1 subnets
O IA 3.3.3.3 [110/129] via 12.1.1.2, 00:09:33, Serial0/0
4.0.0.0/32 is subnetted, 1 subnets
O IA 4.4.4.4 [110/193] via 12.1.1.2, 00:09:33, Serial0/0
5.0.0.0/24 is subnetted, 1 subnets
O E1 5.5.5.0 [110/202] via 12.1.1.2, 00:00:05, Serial0/0
23.0.0.0/24 is subnetted, 1 subnets
O IA 23.1.1.0 [110/128] via 12.1.1.2, 00:09:34, Serial0/0
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, Serial0/0
45.0.0.0/24 is subnetted, 1 subnets
O E1 45.1.1.0 [110/202] via 12.1.1.2, 00:00:06, Serial0/0
R1(config-router)#do show ip ospf database
OSPF Router with ID (1.1.1.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 618 0x80000008 0x005DFD 3
2.2.2.2 2.2.2.2 619 0x80000008 0x008CDD 2
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
2.2.2.2 2.2.2.2 645 0x80000004 0x00F434
3.3.3.3 2.2.2.2 645 0x80000004 0x00499B
4.4.4.4 2.2.2.2 645 0x80000004 0x009D03
23.1.1.0 2.2.2.2 645 0x80000004 0x008652
34.1.1.0 2.2.2.2 645 0x80000004 0x007914
Summary ASB Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
4.4.4.4 2.2.2.2 102 0x80000001 0x008B18
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
5.5.5.0 4.4.4.4 38 0x80000001 0x00D239 0
45.1.1.0 4.4.4.4 40 0x80000001 0x0025C6 0
在R1上存在着3类4类5类LSA.
再将area 1设置成stub 区域，查看路由表和OSPF数据库。
R1(config-router)#do show ip rout
Gateway of last resort is 12.1.1.2 to network 0.0.0.0
34.0.0.0/24 is subnetted, 1 subnets
O IA 34.1.1.0 [110/192] via 12.1.1.2, 00:00:01, Serial0/0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O IA 2.2.2.2 [110/65] via 12.1.1.2, 00:00:01, Serial0/0
3.0.0.0/32 is subnetted, 1 subnets
O IA 3.3.3.3 [110/129] via 12.1.1.2, 00:00:01, Serial0/0
4.0.0.0/32 is subnetted, 1 subnets
O IA 4.4.4.4 [110/193] via 12.1.1.2, 00:00:01, Serial0/0
23.0.0.0/24 is subnetted, 1 subnets
O IA 23.1.1.0 [110/128] via 12.1.1.2, 00:00:01, Serial0/0
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, Serial0/0
O*IA 0.0.0.0/0 [110/65] via 12.1.1.2, 00:00:03, Serial0/0
R1(config-router)#do show ip ospf da
OSPF Router with ID (1.1.1.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 27 0x8000000F 0x006DE8 3
2.2.2.2 2.2.2.2 27 0x8000000F 0x009CC8 2
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 2.2.2.2 42 0x80000001 0x0075C0
2.2.2.2 2.2.2.2 42 0x80000008 0x000B1C
3.3.3.3 2.2.2.2 42 0x80000008 0x005F83
4.4.4.4 2.2.2.2 42 0x80000008 0x00B3EA
23.1.1.0 2.2.2.2 42 0x80000008 0x009C3A
34.1.1.0 2.2.2.2 42 0x80000008 0x008FFB
和原有路由表相比，多出了一条O*IA（三类的默认路由）的路由条目，而没有了O E1的路由（由5类LSA学到的路由）。注意它的cost 值[110/65]，默认下放的cost值是1，可以通过 area 1 default-cost ….修改。如果区域1中有两台ABR可以能过此命令实现选路。在配制stub区域时区域内的所有路由器都要配制成stub区域。
和原有OSPF数据库相比，没有了4类和5类LSA，而是在3类中多出了0.0.0.0 2.2.2.2 42 0x80000001 0x0075C0 一条3类默认路由。
四、 totally stub
在路由表中即有区域内的明细路由还有默认路由，很显然是重复的。
将Area 1设置成Totally stub 区域。
R2(config-router)#area 1 stub no-summary
注意这条命令只在ABR上输入。因为是由ABR来完成过滤。
查看R1的路由表
R1#show ip rout
Gateway of last resort is 12.1.1.2 to network 0.0.0.0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, Serial0/0
O*IA 0.0.0.0/0 [110/65] via 12.1.1.2, 00:03:11, Serial0/0
再查看R1的OSPF数据库
R1#show ip ospf da
OSPF Router with ID (1.1.1.1) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 392 0x80000004 0x005011 3
2.2.2.2 2.2.2.2 303 0x80000006 0x00AEBF 2
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
0.0.0.0 2.2.2.2 311 0x80000001 0x0075C0
和stub区域的路由表和OSPF数据相比没有了3类4类和5类的LSA.取而代之的是一条三类默认路由。
作用 是否下放默认路由
Stub 过滤4类和5类LSA 是（LSA3）Seed cost = 1
Totally stub 过滤3类4类5类LSA 是（LSA3）Seed cost = 1
Totally stub 是cisco私有协议。通过对两种区域的对比可以发现如果要将某一区域划成Stub区域，不如直接划成Totally stub区域。