CCNP-7 OSPF试验3（BSCI）

CCNP-7 OSPF试验3

试验拓扑：

试验要求： R1 R2 R3 通过 FR 相连，形成 hub and spoke 网络， R1 为 hub 路由器，在 R1 R2 R3 上起 OSPF 。

试验目的：掌握 OSPF 在 NBMA 环境下的配置和观察 OSPF 在 NBMA 下特征。

试验配置：

R1 ：

interface Loopback0

 ip address 100.100.100.100 255.255.255.0

 ip ospf network point-to-point

!        

interface Loopback1

 ip address 192.168.1.1 255.255.255.0

 ip ospf network point-to-point

!

interface Serial1/0

 ip address 199.99.1.1 255.255.255.0

 encapsulation frame-relay

 serial restart-delay 0

 frame-relay map ip 199.99.1.1 301 broadcast

 frame-relay map ip 199.99.1.2 301 broadcast

 frame-relay map ip 199.99.1.3 302 broadcast

 no frame-relay inverse-arp

!

router ospf 100

 router-id 100.100.100.100

 log-adjacency-changes

 network 100.100.100.0 0.0.0 .255 area 0

 network 192.168.1.0 0.0.0 .255 area 0

 network 199.99.1.0 0.0.0 .255 area 0

 neighbor 199.99.1.2

 neighbor 199.99.1.3

 

R2 ：

interface Loopback0

 ip address 2.2.2 .2 255.255.255.0

 ip ospf network point-to-point

!        

interface Loopback1

 ip address 192.168.2.1 255.255.255.0

 ip ospf network point-to-point

!

interface Serial1/0

 ip address 199.99.1.2 255.255.255.0

 encapsulation frame-relay

 serial restart-delay 0

 frame-relay map ip 199.99.1.1 103 broadcast

 frame-relay map ip 199.99.1.3 103 broadcast

 no frame-relay inverse-arp

!

router ospf 100

 router-id 2.2.2 .2

 log-adjacency-changes

 network 2.2.2 .0 0.0.0.255 area 0

 network 192.168.2.0 0.0.0 .255 area 0

 network 199.99.1.0 0.0.0 .255 area 0

 neighbor 199.99.1.1

 

R3 ：

interface Loopback0

 ip address 3.3.3 .3 255.255.255.0

 ip ospf network point-to-point

!        

interface Loopback1

 ip address 192.168.3.1 255.255.255.0

 ip ospf network point-to-point

!

interface Serial1/0

 ip address 199.99.1.3 255.255.255.0

 encapsulation frame-relay

 serial restart-delay 0

 frame-relay map ip 199.99.1.1 203 broadcast

 frame-relay map ip 199.99.1.2 203 broadcast

 no frame-relay inverse-arp

!

router ospf 100

 router-id 3.3.3 .3

 log-adjacency-changes

 network 3.3.3 .0 0.0.0.255 area 0

 network 192.168.3.0 0.0.0 .255 area 0

 network 199.99.1.0 0.0.0 .255 area 0

 neighbor 199.99.1.1

 

以上为基本配置，要注意用红颜色标记的部分， 因为在 NBMA 环境下，邻居关系是不会自动建立的，所以要手动添加邻居，这样他们在建立邻居关系的时候发送的不是组播，而是单播。 然后我们用 show ip ospf interface 命令查看接口：

R1#show ip ospf interface

Loopback0 is up, line protocol is up

  Internet Address 100.100.100.100/24, Area 0

  Process ID 100, Router ID 100.100.100.100, Network Type POINT_TO_POINT, Cost: 1

  Transmit Delay is 1 sec, State POINT_TO_POINT,

  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

    oob-resync timeout 40

  Supports Link-local Signaling (LLS)

  Index 3/3, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 0, maximum is 0

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 0, Adjacent neighbor count is 0

  Suppress hello for 0 neighbor(s)

Loopback1 is up, line protocol is up

  Internet Address 192.168.1.1/24, Area 0

  Process ID 100, Router ID 100.100.100.100, Network Type POINT_TO_POINT, Cost: 1

  Transmit Delay is 1 sec, State POINT_TO_POINT,

  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

    oob-resync timeout 40

  Supports Link-local Signaling (LLS)

  Index 2/2, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 0, maximum is 0

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 0, Adjacent neighbor count is 0

  Suppress hello for 0 neighbor(s)

Serial1/0 is up, line protocol is up

  Internet Address 199.99.1.1/24, Area 0

  Process ID 100, Router ID 100.100.100.100, Network Type NON_BROADCAST, Cost: 64

  Transmit Delay is 1 sec, State DR , Priority 1

  Designated Router (ID) 100.100.100.100, Interface address 199.99.1.1

  Backup Designated router (ID) 3.3.3 .3, Interface address 199.99.1.3

  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5

    oob-resync timeout 120

    Hello due in 00:00:28

  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 1

  Last flood scan time is 0 msec, maximum is 4 msec

  Neighbor Count is 2, Adjacent neighbor count is 2

    Adjacent with neighbor 2.2.2 .2

    Adjacent with neighbor 3.3.3 .3  (Backup Designated Router)

  Suppress hello for 0 neighbor(s)

 

R2#show ip ospf interface

Loopback0 is up, line protocol is up

  Internet Address 2.2.2 .2/24, Area 0

  Process ID 100, Router ID 2.2.2 .2, Network Type POINT_TO_POINT, Cost: 1

  Transmit Delay is 1 sec, State POINT_TO_POINT,

  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

    oob-resync timeout 40

  Supports Link-local Signaling (LLS)

  Index 3/3, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 0, maximum is 0

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 0, Adjacent neighbor count is 0

  Suppress hello for 0 neighbor(s)

Loopback1 is up, line protocol is up

  Internet Address 192.168.2.1/24, Area 0

  Process ID 100, Router ID 2.2.2 .2, Network Type POINT_TO_POINT, Cost: 1

  Transmit Delay is 1 sec, State POINT_TO_POINT,

  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

    oob-resync timeout 40

  Supports Link-local Signaling (LLS)

  Index 2/2, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 0, maximum is 0

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 0, Adjacent neighbor count is 0

  Suppress hello for 0 neighbor(s)

Serial1/0 is up, line protocol is up

  Internet Address 199.99.1.2/24, Area 0

  Process ID 100, Router ID 2.2.2 .2, Network Type NON_BROADCAST, Cost: 64

  Transmit Delay is 1 sec, State BDR, Priority 1

  Designated Router (ID) 100.100.100.100, Interface address 199.99.1.1

  Backup Designated router (ID) 2.2.2 .2, Interface address 199.99.1.2

  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5

    oob-resync timeout 120

    Hello due in 00:00:03

  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 1

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 1, Adjacent neighbor count is 1

    Adjacent with neighbor 100.100.100.100  (Designated Router)

  Suppress hello for 0 neighbor(s)

 

R3#show ip ospf interface

Loopback0 is up, line protocol is up

  Internet Address 3.3.3 .3/24, Area 0

  Process ID 100, Router ID 3.3.3 .3, Network Type POINT_TO_POINT, Cost: 1

  Transmit Delay is 1 sec, State POINT_TO_POINT,

  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

    oob-resync timeout 40

  Supports Link-local Signaling (LLS)

  Index 3/3, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 0, maximum is 0

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 0, Adjacent neighbor count is 0

  Suppress hello for 0 neighbor(s)

Loopback1 is up, line protocol is up

  Internet Address 192.168.3.1/24, Area 0

  Process ID 100, Router ID 3.3.3 .3, Network Type POINT_TO_POINT, Cost: 1

  Transmit Delay is 1 sec, State POINT_TO_POINT,

  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

    oob-resync timeout 40

  Supports Link-local Signaling (LLS)

  Index 2/2, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 0, maximum is 0

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 0, Adjacent neighbor count is 0

  Suppress hello for 0 neighbor(s)

Serial1/0 is up, line protocol is up

  Internet Address 199.99.1.3/24, Area 0

  Process ID 100, Router ID 3.3.3 .3, Network Type NON_BROADCAST, Cost: 64

  Transmit Delay is 1 sec, State BDR, Priority 1

  Designated Router (ID) 100.100.100.100, Interface address 199.99.1.1

  Backup Designated router (ID) 3.3.3 .3, Interface address 199.99.1.3

  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5

    oob-resync timeout 120

    Hello due in 00:00:25

  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 1

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 1, Adjacent neighbor count is 1

    Adjacent with neighbor 100.100.100.100  (Designated Router)

  Suppress hello for 0 neighbor(s)

 

要注意在这里用红色标记的部分，接口类型为 NON_BROADCAST ，默认的 HELLO 时间间隔为 30 秒，等待时间和死亡时间为 HELLO 时间间隔的四倍，也就是 120 秒。然后再用 show ip ospf neighbor 查看各自的邻居关系：

R1#show ip ospf neighbor

 

Neighbor ID     Pri   State           Dead Time   Address         Interface

2.2.2 .2           1   FULL/DROTHER    00:01:50    199.99.1.2      Serial1/0

3.3.3 .3           1   FULL/BDR        00:01:47    199.99.1.3      Serial1/0

 

 

R2#show ip ospf neighbor

 

Neighbor ID     Pri   State           Dead Time   Address         Interface

100.100.100.100   1   FULL/DR         00:01:38    199.99.1.1      Serial1/0

 

 

R3#show ip ospf neighbor

 

Neighbor ID     Pri   State           Dead Time   Address         Interface

100.100.100.100   1   FULL/DR         00:01:33    199.99.1.1      Serial1/0

 

可以发现有 DR/BDR 的选择，一般情况下 DR 由 hub 路由器担当。 所以这里我们把 hub 路由器的 router-id 设置为最高，或者修改优先级也可以做到使 hub 路由器成为 DR 的目的，如在 R2 R3 的接口下打上这样的一条命令： ip ospf priority 0 , 配置完后就可以使 R2 R3 丧失 DR/BDR 的选举。

  最后查看以下各自的路由表：

R1#show ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF , IA - OSPF inter area

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2

       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area, * - candidate default, U - per-user static route

       o - ODR, P - periodic downloaded static route

 

Gateway of last resort is not set

 

     2.0.0 .0/24 is subnetted, 1 subnets

O       2.2.2 .0 [110/65] via 199.99.1.2, 00:01:40, Serial1/0

     100.0.0.0/24 is subnetted, 1 subnets

C       100.100.100.0 is directly connected, Loopback0

     3.0.0 .0/24 is subnetted, 1 subnets

O       3.3.3 .0 [110/65] via 199.99.1.3, 00:01:40, Serial1/0

C    199.99.1.0/24 is directly connected, Serial1/0

C    192.168.1.0/24 is directly connected, Loopback1

O    192.168.2.0/24 [110/65] via 199.99.1.2, 00:01:40, Serial1/0

O    192.168.3.0/24 [110/65] via 199.99.1.3, 00:01:40, Serial1/0

 

R2#show ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF , IA - OSPF inter area

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2

       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area, * - candidate default, U - per-user static route

       o - ODR, P - periodic downloaded static route

 

Gateway of last resort is not set

 

     2.0.0 .0/24 is subnetted, 1 subnets

C       2.2.2 .0 is directly connected, Loopback0

     100.0.0.0/24 is subnetted, 1 subnets

O       100.100.100.0 [110/65] via 199.99.1.1, 00:01:45, Serial1/0

     3.0.0 .0/24 is subnetted, 1 subnets

O       3.3.3 .0 [110/65] via 199.99.1.3, 00:01:45, Serial1/0

C    199.99.1.0/24 is directly connected, Serial1/0

O    192.168.1.0/24 [110/65] via 199.99.1.1, 00:01:45, Serial1/0

C    192.168.2.0/24 is directly connected, Loopback1

O    192.168.3.0/24 [110/65] via 199.99.1.3, 00:01:45, Serial1/0

 

R3#show ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF , IA - OSPF inter area

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2

       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area, * - candidate default, U - per-user static route

       o - ODR, P - periodic downloaded static route

 

Gateway of last resort is not set

 

     2.0.0 .0/24 is subnetted, 1 subnets

O       2.2.2 .0 [110/65] via 199.99.1.2, 00:01:41, Serial1/0

     100.0.0.0/24 is subnetted, 1 subnets

O       100.100.100.0 [110/65] via 199.99.1.1, 00:01:41, Serial1/0

     3.0.0 .0/24 is subnetted, 1 subnets

C        3.3.3 .0 is directly connected, Loopback0

C    199.99.1.0/24 is directly connected, Serial1/0

O    192.168.1.0/24 [110/65] via 199.99.1.1, 00:01:41, Serial1/0

O    192.168.2.0/24 [110/65] via 199.99.1.2, 00:01:41, Serial1/0

C    192.168.3.0/24 is directly connected, Loopback1

 

实验中遇到的问题：最初的时候我只在 R2 R3 上作了一个静态的映射，就是到 R1 的映射，自己以为可以通过 OSPF 学习到到达对端 sopke 路由器的路由，可是都配置完成后发现无法 ping 通，查看路由表的时候发现了问题的所在：

C    199.99.1.0/24 is directly connected, Serial1/0

看到了吧，因为三台路由器的 IP 地址在同一网段，所以直连的路由的管理距离为 0 ，而 OSPF 的管理距离为 110 ，所以路由表里只会出现直接的路由，但是如果要达到对端 spoke 路由器，没有做静态映射是无法到达的，所以才出现了 R2 无法 ping 通 R3 的情况：

R2#ping 199.99.1.3

 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 199.99.1.3, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

 

R2#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 0 percent (0/5)

分别在 R2 R3 上加上到达对端 spoke 路由器的静态映射后，就可以 ping 通了。

R2#ping 192.168.3.1

 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.3.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 264/340/428 ms

R2#ping

Protocol [ip]:

Target IP address: 192.168.3.1

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]: y

Source address or interface: 192.168.2.1

Type of service [0]:

Set DF bit in IP header? [no]:

Validate reply data? [no]:

Data pattern [0xABCD]:

Loose, Strict, Record, Timestamp, Verbose[none]:

Sweep range of sizes [n]:

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.3.1, timeout is 2 seconds:

Packet sent with a source address of 192.168.2.1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 332/354/384 ms

实验总结：掌握在 NBMA 环境下面，接口默认的网络类型为 NBMA ，邻居关系不会自动建立，需要手动添加邻居，并且有 DR/BDR 的选举，默认的 HELLO 时间间隔为 30 秒，等待时间和死亡时间为 HELLO 时间间隔的 4 倍， 120 秒。