Hub-and-Spoke 结构具有节约费用、简化配置等优点，在实际网络工程中有着广泛的应用。
实验1: 帧中继环境下NBMA 模式
1.实验目的
通过本实验可以掌握：
（1）帧中继静态映射及broadcast 参数的含义 （2）NBMA 模式下的DR 选举 （3）手工配置OSPF 邻居
（4）NBMA 模式下OSPF 的配置和调试
2.拓扑结构
3.实验配置
R0 三层交换机模拟帧中继交换机配置
frame-relay switching //把该路由器当成帧中继交换机
interface Serial1/1 no ip address
encapsulation frame-relay serial restart-delay 0
clock rate 128000 //该接口为DCE，要配置时钟 no frame-relay inverse-arp frame-relay lmi-type cisco frame-relay intf-type dce
frame-relay route 102 interface Serial1/2 201 frame-relay route 103 interface Serial1/3 301
//“encapsulation frame-relay [ ietf ]”命令用来配置口封装成帧中继，如果不加ietf 参数，帧类型为cisco；如果加ietf 参数，则帧类型为ietf。
interface Serial1/2 no ip address
encapsulation frame-relay serial restart-delay 0 clock rate 128000
no frame-relay inverse-arp frame-relay lmi-type cisco frame-relay intf-type dce
frame-relay route 201 interface Serial1/1 102
interface Serial1/3 no ip address
encapsulation frame-relay serial restart-delay 0 clock rate 128000
frame-relay lmi-type cisco frame-relay intf-type dce
frame-relay route 301 interface Serial1/1 103
R1
interface Loopback0
ip address 1.1.1.1 255.255.255.0 ip ospf network point-to-point !
interface Serial1/1
ip address 123.1.1.1 255.255.255.0 encapsulation frame-relay serial restart-delay 0
frame-relay map ip 123.1.1.3 103 broadcast //帧中继静态映射 frame-relay map ip 123.1.1.2 102 broadcast
no frame-relay inverse-arp //关闭帧中继动态ARP解析 ip ospf network non-broadcast（默认） frame-relay lmi-type cisco !
router ospf 1
log-adjacency-changes
network 1.1.1.0 0.0.0.255 area 0 network 123.1.1.0 0.0.0.255 area 0 neighbor 123.1.1.3 neighbor 123.1.1.2 !
R2
interface Loopback0
ip address 2.2.2.2 255.255.255.0 ip ospf network point-to-point !
interface Serial1/2
ip address 123.1.1.2 255.255.255.0 encapsulation frame-relay
ip ospf priority 0 //配置spoke端OSPF接口优先级为0 ip ospf network non-broadcast（默认） serial restart-delay 0
frame-relay map ip 123.1.1.3 201 broadcast frame-relay map ip 123.1.1.1 201 broadcast frame-relay map ip 123.1.1.2 201 no frame-relay inverse-arp frame-relay lmi-type cisco ! !
router ospf 1
log-adjacency-changes
network 2.2.2.0 0.0.0.255 area 0 network 123.1.1.0 0.0.0.255 area 0
R3
interface Loopback0
ip address 3.3.3.3 255.255.255.0 ip ospf network point-to-point !
!
interface Serial1/3
ip address 123.1.1.3 255.255.255.0 encapsulation frame-relay ip ospf priority 0
ip ospf network non-broadcast（默认） serial restart-delay 0
frame-relay map ip 123.1.1.3 301
frame-relay map ip 123.1.1.1 301 broadcast frame-relay map ip 123.1.1.2 301 broadcast no frame-relay inverse-arp !
router ospf 1
log-adjacency-changes
network 3.3.3.0 0.0.0.255 area 0 network 123.1.1.0 0.0.0.255 area 0
4.实验调试
R3#sh ip ospf interface s1/3
Serial1/3 is up, line protocol is up
Internet Address 123.1.1.3/24, Area 0
Process ID 1, Router ID 3.3.3.3, Network Type NON_BROADCAST, Cost: 64 Transmit Delay is 1 sec, State DROTHER, Priority 0
Designated Router (ID) 1.1.1.1, Interface address 123.1.1.1 No backup designated router on this network
Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5 oob-resync timeout 120 Hello due in 00:00:20
Supports Link-local Signaling (LLS) Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 2
Last flood scan time is 4 msec, maximum is 4 msec Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 1.1.1.1 (Designated Router) Suppress hello for 0 neighbor(s)
R1#show ip route ospf
2.0.0.0/24 is subnetted, 1 subnets
O 2.2.2.0 [110/65] via 123.1.1.2, 00:00:25, Serial1/1 3.0.0.0/24 is subnetted, 1 subnets
O 3.3.3.0 [110/65] via 123.1.1.3, 00:00:25, Serial1/1
R1#ping 123.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 123.1.1.1, timeout is 2 seconds:
..... //没有配置frame-relay map ip 123.1.1.1 102，不能ping通自己。 Success rate is 0 percent (0/5) R1#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
Success rate is 100 percent (5/5), round-trip min/avg/max = 60/91/128 ms R1#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
Success rate is 100 percent (5/5), round-trip min/avg/max = 60/80/120 ms
R2#show ip route
1.0.0.0/24 is subnetted, 1 subnets
O 1.1.1.0 [110/65] via 123.1.1.1, 00:05:04, Serial1/2 2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback0 3.0.0.0/24 is subnetted, 1 subnets
O 3.3.3.0 [110/65] via 123.1.1.3, 00:05:04, Serial1/2 123.0.0.0/24 is subnetted, 1 subnets
C 123.1.1.0 is directly connected, Serial1/2 R2#traceroute 3.3.3.3
Type escape sequence to abort. Tracing the route to 3.3.3.3
1 123.1.1.1 136 msec 80 msec 56 msec 2 123.1.1.3 144 msec * 144 msec
从以上输出表明，到达网络“3.3.3.0/24”的路由条目的下一跳地址为“134.1.1.3”， 而不是“134.1.1.1”，所以，在R2 的s1/2的接口上必须有到134.1.1.3 的映射 “frame-relay map ip 134.1.1.3 201 broadcast”。 【技术要点】 （1）在帧中继网络上，OSPF 接口缺省的网络类型为NON_BROADCAST。在这种模式下，OSPF 不会在帧中继接口上发送Hello 包，因此无法建立最基本的邻接关系。可以手工使用“neighbor”命令来指定邻居，这时Hello 包以单播形式传送；
（2）NBMA 属于多路访问网络，所以要进行DR 选举。由于Hello 包只能传1 跳，所以在Hub-and-Spoke 结构中，必须控制处于“Hub”端的路由器为DR,最保险的办法就是将“Spoke”端接口优先级配置为0，使之不参与DR 选举，“Hub”端的路由器自然就成为DR。否则，可能会导致路由学习不正常。
实验2：帧中继环境下BMA 模式
1.实验目的
（1）帧中继静态映射及broadcast 参数的含义 （2）BMA 模式下的DR 选举
（3）BMA 模式下OSPF 的配置和调试
2.拓扑结构
拓扑如实验1图。
3.实验配置
只需要将R1、R2、R3的模式修改一下即可，例如： R1(config-if)# ip ospf network broadcast
interface Loopback0
ip address 1.1.1.1 255.255.255.0 ip ospf network point-to-point !
interface Serial1/1
ip address 123.1.1.1 255.255.255.0 encapsulation frame-relay
ip ospf network broadcast //在接口更改ospf网络模式 serial restart-delay 0 clock rate 128000
frame-relay map ip 123.1.1.3 103 broadcast frame-relay map ip 123.1.1.2 102 broadcast no frame-relay inverse-arp frame-relay lmi-type cisco !
router ospf 1
log-adjacency-changes
network 1.1.1.0 0.0.0.255 area 0 network 123.1.1.0 0.0.0.255 area 0 其他设备如上更改 不再详细配置
4.实验调试
R1#sh ip ospf int s1/1
Serial1/1 is up, line protocol is up
Internet Address 123.1.1.1/24, Area 0
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 64 //网络类型为BROADCAST
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 1.1.1.1, Interface address 123.1.1.1 No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:00
Supports Link-local Signaling (LLS) Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 2
Last flood scan time is 0 msec, maximum is 4 msec Neighbor Count is 2, Adjacent neighbor count is 2 Adjacent with neighbor 123.1.1.2 Adjacent with neighbor 123.1.1.3 Suppress hello for 0 neighbor(s)
R1#show ip route ospf
2.0.0.0/24 is subnetted, 1 subnets
O 2.2.2.0 [110/65] via 123.1.1.2, 00:07:17, Serial1/1 3.0.0.0/24 is subnetted, 1 subnets
O 3.3.3.0 [110/65] via 123.1.1.3, 00:07:17, Serial1/1 【技术要点】
（1）在Hub-and-Spoke 结构中，BMA 也要控制DR 选举，确保处于“Hub”端的路由器 为DR，实施方法和实验1 一样；
（2）BMA 模式下，邻居关系自动通过Hello 包建立和维持。
实验3：帧中继环境下点到点（子接口）模式
点到点模式(point-to-point)
注意要使用frame-relay interface-dlci命令。 也不需要手动指定邻居
1.实验目的
（1）帧中继子接口下静态映射 （2）点到点模式的特征
（2）点到点模式下OSPF 的配置和调试
2.拓扑结构
实验1图。
3.实验配置
R1
interface Loopback0
ip address 1.1.1.1 255.255.255.0 ip ospf network point-to-point !
interface Serial1/1 no ip address
encapsulation frame-relay serial restart-delay 0 no frame-relay inverse-arp !
interface Serial1/1.1 point-to-point ip address 123.1.1.1 255.255.255.0 frame-relay interface-dlci 102 !
interface Serial1/1.2 point-to-point ip address 123.1.2.1 255.255.255.0 frame-relay interface-dlci 103 !
router ospf 1
router-id 1.1.1.1 log-adjacency-changes
network 1.1.1.0 0.0.0.255 area 0 network 123.1.1.0 0.0.0.255 area 0 network 123.1.2.0 0.0.0.255 area 0
R2
interface Loopback0
ip address 2.2.2.2 255.255.255.0 ip ospf network point-to-point !
interface Serial1/2 no ip address
encapsulation frame-relay serial restart-delay 0 no frame-relay inverse-arp !
interface Serial1/2.1 point-to-point ip address 123.1.1.2 255.255.255.0 frame-relay interface-dlci 201 !
router ospf 1
router-id 2.2.2.2 log-adjacency-changes
network 2.2.2.0 0.0.0.255 area 0 network 123.1.1.0 0.0.0.255 area 0
R3
interface Loopback0
ip address 3.3.3.3 255.255.255.0 ip ospf network point-to-point !
interface Serial1/3 no ip address
encapsulation frame-relay serial restart-delay 0 no frame-relay inverse-arp !
interface Serial1/3.1 point-to-point ip address 123.1.2.2 255.255.255.0 frame-relay interface-dlci 301 !
router ospf 1
router-id 3.3.3.3 log-adjacency-changes
network 0.0.0.0 255.255.255.255 area 0
4.实验调试
R1#sh ip ospf int s1/1.1
Serial1/1.1 is up, line protocol is up Internet Address 123.1.1.1/24, Area 0
Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 64 //点到点模式下，Hello周期为10秒
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:08
Supports Link-local Signaling (LLS) Index 2/2, flood queue length 0 Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 4 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 2.2.2.2 Suppress hello for 0 neighbor(s) R1#sh ip ospf neighbor detail
Neighbor 3.3.3.3, interface address 123.1.2.2 In the area 0 via interface Serial1/1.2
Neighbor priority is 0, State is FULL, 6 state changes DR is 0.0.0.0 BDR is 0.0.0.0 Options is 0x52
LLS Options is 0x1 (LR) Dead timer due in 00:00:38 Neighbor is up for 00:49:51
Index 1/1, retransmission queue length 0, number of retransmission 1 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
Last retransmission scan length is 1, maximum is 1
Last retransmission scan time is 4 msec, maximum is 4 msec Neighbor 2.2.2.2, interface address 123.1.1.2
In the area 0 via interface Serial1/1.1
Neighbor priority is 0, State is FULL, 6 state changes DR is 0.0.0.0 BDR is 0.0.0.0 Options is 0x52
LLS Options is 0x1 (LR) Dead timer due in 00:00:38 Neighbor is up for 00:49:11
Index 2/2, retransmission queue length 0, number of retransmission 0 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
Last retransmission scan length is 0, maximum is 0
Last retransmission scan time is 0 msec, maximum is 0 msec 【技术要点】
1. 点到点模式的DR和BDR是“0.0.0.0”；
2. 点到点模式下，每个子接口需要配置不同的网络； 3. 点到点模式下，Hello周期为10秒。
进入子接口时选point to point,就不能使用frame-relay map命令了,只能用frame-relay interface-dlci做映射,选multipoint时候2者都可以用 点到点子接口就一条PVC所以只需用frame-relay interface-dlci来分配一个dlci号就行(而且是必须的)
多点子接口有多个PVC所以用frame-relay map来做映射，区别不同的PVC，因为路由器在启用子接口时inverse-arp不起作用的
4. 点到多点广播模式(point-to-multipoint)
1.实验目的
（1）帧中继子接口下静态映射 （2）点到多点模式的特征
（3）点到多点模式下OSPF 的配置和调试
2.拓扑结构
实验1拓扑图
3.实验配置
R1
interface Loopback0
ip address 1.1.1.1 255.255.255.0 ip ospf network point-to-point !
interface Serial1/1 no ip address
encapsulation frame-relay serial restart-delay 0
no frame-relay inverse-arp !
interface Serial1/1.1 multipoint ip address 123.1.1.1 255.255.255.0
ip ospf network point-to-multipoint
frame-relay map ip 123.1.1.3 103 broadcast frame-relay map ip 123.1.1.2 102 broadcast no frame-relay inverse-arp !
router ospf 1 router-id 1.1.1.1
log-adjacency-changes
network 1.1.1.0 0.0.0.255 area 0 network 123.1.1.0 0.0.0.255 area 0
R2
interface Loopback0
ip address 2.2.2.2 255.255.255.0 ip ospf network point-to-point !
interface Serial1/2
ip address 123.1.1.2 255.255.255.0 encapsulation frame-relay
ip ospf network point-to-multipoint serial restart-delay 0
frame-relay map ip 123.1.1.1 201 broadcast no frame-relay inverse-arp !
router ospf 1 router-id 2.2.2.2
log-adjacency-changes
network 2.2.2.0 0.0.0.255 area 0 network 123.1.1.0 0.0.0.255 area 0
R3
interface Loopback0
ip address 3.3.3.3 255.255.255.0 ip ospf network point-to-point !
interface Serial1/3
ip address 123.1.1.3 255.255.255.0 encapsulation frame-relay
ip ospf network point-to-multipoint serial restart-delay 0
frame-relay map ip 123.1.1.1 301 broadcast no frame-relay inverse-arp !
router ospf 1
router-id 3.3.3.3
log-adjacency-changes
network 3.3.3.0 0.0.0.255 area 0 network 123.1.1.0 0.0.0.255 area 0 R2#sh ip ospf interface s1/2 Serial1/2 is up, line protocol is up
Internet Address 123.1.1.2/24, Area 0
Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_MULTIPOINT, Cost: 64 // POINT_TO_MULTIPOINT 模式下，Hello 周期为30 秒
Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT,
Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5 oob-resync timeout 120 Hello due in 00:00:06
Supports Link-local Signaling (LLS) Index 3/3, flood queue length 0 Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 1.1.1.1 Suppress hello for 0 neighbor(s) R1#sh ip route ospf
2.0.0.0/24 is subnetted, 1 subnets
O 2.2.2.0 [110/65] via 123.1.1.2, 00:18:40, Serial1/1.1 3.0.0.0/24 is subnetted, 1 subnets
O 3.3.3.0 [110/65] via 123.1.1.3, 00:18:40, Serial1/1.1 123.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
O 123.1.1.3/32 [110/64] via 123.1.1.3, 00:18:40, Serial1/1.1 O 123.1.1.2/32 [110/64] via 123.1.1.2, 00:18:40, Serial1/1.1 R3#sh ip route ospf
1.0.0.0/24 is subnetted, 1 subnets
O 1.1.1.0 [110/65] via 123.1.1.1, 00:20:29, Serial1/3 2.0.0.0/24 is subnetted, 1 subnets
O 2.2.2.0 [110/129] via 123.1.1.1, 00:20:29, Serial1/3 123.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
O 123.1.1.2/32 [110/128] via 123.1.1.1, 00:20:29, Serial1/3 O 123.1.1.1/32 [110/64] via 123.1.1.1, 00:20:29, Serial1/3 以上输出表明在点到多点模式中，在路由表中会产生该网段其他各个接口的主机路由，因此在做帧中继映射的时候，只做到中心点的就可以了 【技术要点】
（1）点到多点广播模式可以被看成多个点到点接口的集合，然而和点到点不同的是帧中继接口是在同一子网上；
（2）在点到多点模式中，不需要选举DR/BDR；
（3）Hello 包每30 秒发送一次，无需手工配置邻居。
R2#sh ip ospf neighbor detail
Neighbor 1.1.1.1, interface address 123.1.1.1 In the area 0 via interface Serial1/2
Neighbor priority is 0, State is FULL, 6 state changes DR is 0.0.0.0 BDR is 0.0.0.0 Options is 0x52
LLS Options is 0x1 (LR)
Dead timer due in 00:01:30 Neighbor is up for 00:08:29
Index 1/1, retransmission queue length 0, number of retransmission 0 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
Last retransmission scan length is 0, maximum is 0
Last retransmission scan time is 0 msec, maximum is 0 msec
5. 点到多点非广播模式(point-to-multipoint broadcast)
需要修改三个地方： 模式加non-broadcast
帧中继映射去掉broadcast 设置邻居 例如：
R1(config-if)#ip ospf network point-to-multipoint non-broadcast R1(config-if)#frame-relay map ip 123.1.1.2 102 R1(config-if)#frame-relay map ip 123.1.1.3 103 R1(config-router)#neighbor 123.1.1.2 R1(config-router)#neighbor 123.1.1.3
R2、R3不需要配置neighbor，只要一方配置了就可以
R2(config-if)#ip ospf network point-to-multipoint non-broadcast R2(config-if)#frame-relay map ip 123.1.1.1 201 这种模式下使用单播来发送OSPF分组
6. 非广播模式(non-broadcast)
只要将广播模式中R1、R2、R3的模式修改一下即可 R1(config-if)#ip ospf network non-broadcast 这种模式使用单播发送hello
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