实验需求：
1：配置帧中继交换机PVC链路；
2：配置area0区域，指定合适DR，要求自动形成邻接关系；
3：使用虚链路解决区域分隔问题；
4：配置路由总结减少路由表条目；
5：采用合适的特殊区域减少LSA泛洪；
6：保证所有路由器可以ping通任意接口。
我们查看一些路由器的配置以及其路由表（为减少空间，路由表上的注释已去掉）：
FRSW#show running-config
interface Serial1/0
no ip address
encapsulation frame-relay
serial restart-delay 0
clock rate 64000
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 203 interface Serial1/1 302
frame-relay route 204 interface Serial1/2 402
R1#show running-config
router ospf 110
router-id 11.11.11.11
log-adjacency-changes
area 1 stub
network 11.11.11.0 0.0.0.255 area 1
network 0.0.0.0 255.255.255.255 area 1
R1#show ip route
Gateway of last resort is 12.1.1.2 to network 0.0.0.0
1.0.0.0/24 is subnetted, 4 subnets
C 1.1.1.0 is directly connected, Loopback10
C 1.1.2.0 is directly connected, Loopback11
C 1.1.3.0 is directly connected, Loopback12
C 1.1.4.0 is directly connected, Loopback13
11.0.0.0/24 is subnetted, 1 subnets
C 11.11.11.0 is directly connected, Loopback100
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, Serial1/1
O*IA 0.0.0.0/0 [110/65] via 12.1.1.2, 00:25:19, Serial1/1
R2#show ip route
34.0.0.0/24 is subnetted, 1 subnets
C 34.1.1.0 is directly connected, Serial1/2
1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
O 1.1.0.0/16 is a summary, 00:26:40, Null0
O 1.1.1.1/32 [110/65] via 12.1.1.1, 00:26:40, Serial1/0
O 1.1.3.1/32 [110/65] via 12.1.1.1, 00:26:40, Serial1/0
O 1.1.2.1/32 [110/65] via 12.1.1.1, 00:26:40, Serial1/0
O 1.1.4.1/32 [110/65] via 12.1.1.1, 00:26:40, Serial1/0
35.0.0.0/24 is subnetted, 1 subnets
O IA 35.1.1.0 [110/128] via 34.1.1.3, 00:06:22, Serial1/2
2.0.0.0/24 is subnetted, 2 subnets
C 2.2.2.0 is directly connected, Loopback10
C 2.2.3.0 is directly connected, Loopback11
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 34.1.1.3, 00:06:23, Serial1/2
4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/65] via 34.1.1.4, 00:06:23, Serial1/2
5.0.0.0/32 is subnetted, 1 subnets
O IA 5.5.5.5 [110/129] via 34.1.1.3, 00:06:23, Serial1/2
7.0.0.0/32 is subnetted, 1 subnets
O IA 7.7.7.7 [110/129] via 34.1.1.4, 00:06:23, Serial1/2
8.0.0.0/32 is subnetted, 2 subnets
O IA 8.8.8.8 [110/193] via 34.1.1.4, 00:05:25, Serial1/2
O IA 8.8.88.8 [110/193] via 34.1.1.4, 00:05:25, Serial1/2
78.0.0.0/24 is subnetted, 1 subnets
O IA 78.1.1.0 [110/192] via 34.1.1.4, 00:06:23, Serial1/2
56.0.0.0/24 is subnetted, 1 subnets
O E2 56.1.1.0 [110/20] via 34.1.1.3, 00:06:23, Serial1/2
11.0.0.0/32 is subnetted, 1 subnets
O 11.11.11.11 [110/65] via 12.1.1.1, 00:26:41, Serial1/0
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, Serial1/0
47.0.0.0/24 is subnetted, 1 subnets
O IA 47.1.1.0 [110/128] via 34.1.1.4, 00:06:23, Serial1/2
可以看到R2的路由表仍然是个庞然大物。
R3#show running-config
router ospf 110
router-id 33.33.33.33
log-adjacency-changes
area 4 nssa no-redistribution no-summary
network 3.3.3.0 0.0.0.255 area 0
network 34.1.1.0 0.0.0.255 area 0
network 35.1.1.0 0.0.0.255 area 4
R4#show running-config
router ospf 110
router-id 44.44.44.44
log-adjacency-changes
area 2 virtual-link 77.77.77.77
network 4.4.4.0 0.0.0.255 area 0
network 34.1.1.0 0.0.0.255 area 0
network 47.1.1.0 0.0.0.255 area 2
R5#show running-config
router ospf 110
router-id 55.55.55.55
log-adjacency-changes
area 4 nssa
redistribute rip subnets
network 5.5.5.0 0.0.0.255 area 4
network 35.1.1.0 0.0.0.255 area 4
router rip
version 2
redistribute ospf 110 metric 1
network 56.0.0.0
no auto-summary
R5#show ip route
Gateway of last resort is 35.1.1.3 to network 0.0.0.0
35.0.0.0/24 is subnetted, 1 subnets
C 35.1.1.0 is directly connected, Serial1/0
5.0.0.0/24 is subnetted, 1 subnets
C 5.5.5.0 is directly connected, Loopback10
6.0.0.0/24 is subnetted, 3 subnets
R 6.6.6.0 [120/1] via 56.1.1.6, 00:00:18, Serial1/1
R 6.6.7.0 [120/1] via 56.1.1.6, 00:00:18, Serial1/1
R 6.6.8.0 [120/1] via 56.1.1.6, 00:00:18, Serial1/1
56.0.0.0/24 is subnetted, 1 subnets
C 56.1.1.0 is directly connected, Serial1/1
O*IA 0.0.0.0/0 [110/65] via 35.1.1.3, 00:25:59, Serial1/0
由于做了特殊区域，R5的路由表相当整洁。
R6#show running-config
router rip
version 2
network 6.0.0.0
network 56.0.0.0
no auto-summary
R6# sh ip route
Gateway of last resort is 56.1.1.5 to network 0.0.0.0
35.0.0.0/24 is subnetted, 1 subnets
R 35.1.1.0 [120/1] via 56.1.1.5, 00:00:15, Serial1/0
5.0.0.0/24 is subnetted, 1 subnets
R 5.5.5.0 [120/1] via 56.1.1.5, 00:00:15, Serial1/0
6.0.0.0/24 is subnetted, 3 subnets
C 6.6.6.0 is directly connected, Loopback10
C 6.6.7.0 is directly connected, Loopback11
C 6.6.8.0 is directly connected, Loopback12
56.0.0.0/24 is subnetted, 1 subnets
C 56.1.1.0 is directly connected, Serial1/0
R* 0.0.0.0/0 [120/1] via 56.1.1.5, 00:00:15, Serial1/0
R6的路由表由于下放了默认路由同样整洁。
R7#show running-config | b r o
router ospf 110
router-id 77.77.77.77
log-adjacency-changes
area 2 virtual-link 44.44.44.44
area 3 stub no-summary
network 7.7.7.0 0.0.0.255 area 2
network 47.1.1.0 0.0.0.255 area 2
network 78.1.1.0 0.0.0.255 area 3
R8#show running-config | b r o
router ospf 110
router-id 88.88.88.88
log-adjacency-changes
area 3 stub
network 8.8.0.0 0.0.255.255 area 3
network 78.1.1.0 0.0.0.255 area 3
R8#show ip route
Gateway of last resort is 78.1.1.7 to network 0.0.0.0
8.0.0.0/24 is subnetted, 2 subnets
C 8.8.8.0 is directly connected, Loopback10
C 8.8.88.0 is directly connected, Loopback11
78.0.0.0/24 is subnetted, 1 subnets
C 78.1.1.0 is directly connected, Serial1/0
O*IA 0.0.0.0/0 [110/65] via 78.1.1.7, 00:15:31, Serial1/0
R8由于是末节区域，做个stub可以看到路由表非常整洁。
做下测试：
R8#ping 11.11.11.11 source 8.8.88.8
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 11.11.11.11, timeout is 2 seconds:
Packet sent with a source address of 8.8.88.8
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 44/70/88 ms
R8#ping 6.6.6.6 source 8.8.88.8
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 6.6.6.6, timeout is 2 seconds:
Packet sent with a source address of 8.8.88.8
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 68/91/116 ms
实验完成。
