数据链路层解析

数据链路层解析

1. 案例1：MAC地址表及邻居信息查看
2. 案例2：配置接口速率及双工模式
3. 案例3：配置交换机管理IP

1 案例1：MAC地址表及邻居信息查看

1.1 问题

本例要求为修改计算机名并加入工作组：

1）查看交换机MAC地址表

2）查看CISCO设备邻居信息

1.2 方案

网络拓扑，如图-1所示。

 

图-1

1.3 步骤

实现此案例需要按照如下步骤进行。

步骤一：查看交换机sw1的mac地址表

1）在PC1上ping PC2:192.168.1.2：

1. PC>ipconfig /all
2. FastEthernet0 Connection:(default port)
3. Connection-specific DNS Suffix..: 
4. Physical Address................: 00E0.B079.7815
5. Link-local IPv6 Address.........: FE80::2E0:B0FF:FE79:7815
6. IP Address......................: 192.168.1.1
7. Subnet Mask.....................: 255.255.255.0
8. Default Gateway.................: 0.0.0.0
9. DNS Servers.....................: 0.0.0.0
10. DHCP Servers....................: 0.0.0.0
11. DHCPv6 Client DUID..............: 00-01-00-01-E3-E0-53-04-00-E0-B0-79-78-15
13. PC>ping 192.168.1.2
14. Pinging 192.168.1.2 with 32 bytes of data:
15. Reply from 192.168.1.2: bytes=32 time=1ms TTL=128
16. Reply from 192.168.1.2: bytes=32 time=0ms TTL=128
17. Reply from 192.168.1.2: bytes=32 time=1ms TTL=128
18. Reply from 192.168.1.2: bytes=32 time=0ms TTL=128
19. Ping statistics for 192.168.1.2:
20. Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
21. Approximate round trip times in milli-seconds:
22. Minimum = 0ms, Maximum = 1ms, Average = 0ms

2）查看PC2的IP信息

1. PC>ipconfig /all
2. FastEthernet0 Connection:(default port)
3. Connection-specific DNS Suffix..: 
4. Physical Address................: 0003.E49E.6445
5. Link-local IPv6 Address.........: FE80::203:E4FF:FE9E:6445
6. IP Address......................: 192.168.1.2
7. Subnet Mask.....................: 255.255.255.0
8. Default Gateway.................: 0.0.0.0
9. DNS Servers.....................: 0.0.0.0
10. DHCP Servers....................: 0.0.0.0
11. DHCPv6 Client DUID..............: 00-01-00-01-DB-A7-C6-5E-00-03-E4-9E-64-45

3）在查看交换机sw1的mac地址表

1. Switch#hostname SW1
2. SW1#show mac-address-table
3. Mac Address Table
4. -------------------------------------------
5. Vlan Mac Address Type Ports
6. ---- ----------- -------- -----
7. 1 0003.e49e.6445 DYNAMIC Fa0/2
8. 1 0010.1148.9309 DYNAMIC Fa0/24
9. 1 00e0.b079.7815 DYNAMIC Fa0/1

步骤二：查看交换机sw1邻居信息

1）更改交换机sw2的主机名

1. Switch>enable
2. SW2#configure terminal
3. SW2(config)#hostname SW2
4. SW2(config)#

2）进入交换机SW1特权模式通过命令查看CISCO设备邻居信息：

1. Switch#show cdp neighbors
2. Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
3. S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
4. Device ID    Local Intrfce  Holdtme  Capability   Platform    Port ID
5. SW2             Fas 0/24        174         S          2950       Fas 0/9  

案例2：配置接口速率及双工模式

2.1 问题

配置交换机接口双工模式为半双工，端口速率为10M并查看

2.2 方案

网络拓扑图如图-2

 

图-2

2.3 步骤

实现此案例需要按照如下步骤进行

步骤一：配置交换机接口模式

1. Switch>enable
2. Switch#configure terminal
3. Switch(config)#interface fastEthernet 0/24
4. Switch(config-if)#duplex half
5. Switch(config-if)#speed 10
6. Switch#show interfaces fastEthernet 0/24
7. FastEthernet0/24 is up, line protocol is up (connected)
8. Hardware is Lance, address is 00d0.5807.8301 (bia 00d0.5807.8301)
9. BW 10000 Kbit, DLY 1000 usec,
10. reliability 255/255, txload 1/255, rxload 1/255
11. Encapsulation ARPA, loopback not set
12. Keepalive set (10 sec)
13. Half-duplex, 10Mb/s
14. input flow-control is off, output flow-control is off
15. ARP type: ARPA, ARP Timeout 04:00:00
16. Last input 00:00:08, output 00:00:05, output hang never
17. Last clearing of "show interface" counters never
18. Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
19. Queueing strategy: fifo
20. Output queue :0/40 (size/max)
21. 5 minute input rate 0 bits/sec, 0 packets/sec
22. 5 minute output rate 0 bits/sec, 0 packets/sec
23. 956 packets input, 193351 bytes, 0 no buffer
24. Received 956 broadcasts, 0 runts, 0 giants, 0 throttles
25. 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
26. 0 watchdog, 0 multicast, 0 pause input
27. 0 input packets with dribble condition detected
28. 2357 packets output, 263570 bytes, 0 underruns
29. 0 output errors, 0 collisions, 10 interface resets
30. 0 babbles, 0 late collision, 0 deferred
31. 0 lost carrier, 0 no carrier
32. 0 output buffer failures, 0 output buffers swapped out
33. Switch#
34. 最长 = 0ms，平均 = 0ms

3 案例3：配置交换机管理IP

3.1 问题

配置交换机管理IP为192.168.1.1 ，默认网关为192.168.1.100

3.2 方案

网络拓扑图如图-3

 

图-3

3.3 步骤

实现此案例需要按照如下步骤进行

步骤一：配置交换机接口模式

1）配置路由器R1的接口IP作为192.168.1.0网段的网关地址

1. Router>enable
2. Router#configure terminal
3. Router(config)#interface fastEthernet 0/0
4. Router(config-if)#ip address 192.168.1.100
5. Router(config-if)#ip address 192.168.1.100 255.255.255.0
6. Router(config-if)#no shutdown

2）配置交换机管理IP和网关地址

1. Switch(config)#interface vlan 1
2. Switch(config-if)#ip address 192.168.1.1 255.255.255.0
3. Switch(config-if)#no shutdown
4. Switch(config-if)#exit
5. Switch(config)#ip default-gateway 192.168.1.100

3）用ping命令进行测试

1. PC>ipconfig
2. FastEthernet0 Connection:(default port)
3. Link-local IPv6 Address.........: FE80::200:CFF:FEE4:90B0
4. IP Address......................: 192.168.1.2
5. Subnet Mask.....................: 255.255.255.0
6. Default Gateway.................: 192.168.1.100
8. PC>ping 192.168.1.1
9. Pinging 192.168.1.1 with 32 bytes of data:
10. Request timed out.
11. Reply from 192.168.1.1: bytes=32 time=0ms TTL=255
12. Reply from 192.168.1.1: bytes=32 time=3ms TTL=255
13. Reply from 192.168.1.1: bytes=32 time=0ms TTL=255
14. Ping statistics for 192.168.1.1:
15. Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),
16. Approximate round trip times in milli-seconds:
17. Minimum = 0ms, Maximum = 3ms, Average = 1ms
19. PC>ping 192.168.1.100
20. Pinging 192.168.1.100 with 32 bytes of data:
21. Reply from 192.168.1.100: bytes=32 time=50ms TTL=255
22. Reply from 192.168.1.100: bytes=32 time=0ms TTL=255
23. Reply from 192.168.1.100: bytes=32 time=0ms TTL=255
24. Reply from 192.168.1.100: bytes=32 time=0ms TTL=255
25. Ping statistics for 192.168.1.100:
26. Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
27. Approximate round trip times in milli-seconds:
28. Minimum = 0ms, Maximum = 50ms, Average = 12ms