Vlan的划分
1.1 問題
VLAN(虛擬局域網)是對連接到的第二層交換機端口的網絡用戶的邏輯分段,不受網絡用戶的物理位置限制而根據用戶需求進行網絡分段。 一個VLAN可以在一個交換機或者跨交換機實現。VLAN可以根據網絡用戶的位置、作用、部門或者根據網絡用戶所使用的應用程序和協議來進行分組。基於交 換機的虛擬局域網能夠為局域網解決沖突域、廣播域、帶寬問題。
- 按企業部門規划vlan
1.2 方案
在交換機上創建vlan2、vlan3,參照如下網絡拓撲如圖-1所示:

圖-1
1.3 步驟
實現此案例需要按照如下步驟進行。
步驟一:客戶端與交換機相連
1)為了使同vlan在交換機上可以通信,需要給同vlan客戶端配置同網段IP地址,如圖-2、圖-3所示

圖-2

圖-3
分別配置為192.168.1.1、192.169.1.2;192.168.2.1、192.168.2.2;192.168.3.1、192.168.3.2;
2)在交換機上創建vlan2 和vlan3並將指定的接口划分到相對應的vlan下
- Switch >enable
- Switch#configure terminal
- Switch(config)#vlan 2
- Switch(config-vlan)#exit
- Switch(config)#vlan 3
- Switch(config-vlan)#exit
- Switch(config)#interface fastEthernet 0/3
- Switch(config-if)#switchport access vlan 2
- Switch(config-if)#exit
- Switch(config)#interface fastEthernet 0/4
- Switch(config-if)#switchport access vlan 2
- Switch(config-if)#exit
- Switch(config)#interface fastEthernet 0/5
- Switch(config-if)#switchport access vlan 3
- Switch(config-if)#exit
- Switch(config)#interface fastEthernet 0/6
- Switch(config-if)#switchport access vlan 3
3)在交換機上查看vlan信息,可以看到創建的vlan以及vlan下的接口
- Switch>enable
- Switch#show vlan
- VLAN Name Status Ports
- ---- -------------------------------- --------- -------------------------------
- 1 default active Fa0/1, Fa0/2, Fa0/7, Fa0/8
- Fa0/9, Fa0/10, Fa0/11, Fa0/12
- Fa0/13, Fa0/14, Fa0/15, Fa0/16
- Fa0/17, Fa0/18, Fa0/19, Fa0/20
- Fa0/21, Fa0/22, Fa0/23, Fa0/24
- 2 VLAN0002 active Fa0/3, Fa0/4
- 3 VLAN0003 active Fa0/5, Fa0/6
- 1002 fddi-default act/unsup
- 1003 token-ring-default act/unsup
- 1004 fddinet-default act/unsup
- 1005 trnet-default act/unsup
- VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
- ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
- 1 enet 100001 1500 - - - - - 0 0
- 2 enet 100002 1500 - - - - - 0 0
- 3 enet 100003 1500 - - - - - 0 0
- 1002 fddi 101002 1500 - - - - - 0 0
- 1003 tr 101003 1500 - - - - - 0 0
- 1004 fdnet 101004 1500 - - - ieee - 0 0
- 1005 trnet 101005 1500 - - - ibm - 0 0
- Remote SPAN VLANs
- ------------------------------------------------------------------------------
- Primary Secondary Type Ports
- ------- --------- ----------------- ------------------------------------------
4)在客戶端測試網絡的連通性
在192.168.1.0/24的客戶機上測試1.0網段的連通性
- PC1>ping 192.168.1.2
- Pinging 192.168.1.2 with 32 bytes of data:
- Reply from 192.168.1.2: bytes=32 time=11ms TTL=128
- Reply from 192.168.1.2: bytes=32 time=1ms TTL=128
- Reply from 192.168.1.2: bytes=32 time=1ms TTL=128
- Reply from 192.168.1.2: bytes=32 time=4ms TTL=128
- Ping statistics for 192.168.1.2:
- Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 1ms, Maximum = 11ms, Average = 4ms
5)在192.168.2.0/24的客戶機上測試2.0網段的連通性
- PC>ping 192.168.2.2
- Pinging 192.168.2.2 with 32 bytes of data:
- Reply from 192.168.2.2: bytes=32 time=1ms TTL=128
- Reply from 192.168.2.2: bytes=32 time=0ms TTL=128
- Reply from 192.168.2.2: bytes=32 time=0ms TTL=128
- Reply from 192.168.2.2: bytes=32 time=0ms TTL=128
- Ping statistics for 192.168.2.2:
- Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 0ms, Maximum = 1ms, Average = 0ms
6)在192.168.3.0/24的客戶機上測試3.0網段的連通性
- PC>ping 192.168.3.2
- Pinging 192.168.3.2 with 32 bytes of data:
- Reply from 192.168.3.2: bytes=32 time=1ms TTL=128
- Reply from 192.168.3.2: bytes=32 time=0ms TTL=128
- Reply from 192.168.3.2: bytes=32 time=0ms TTL=128
- Reply from 192.168.3.2: bytes=32 time=1ms TTL=128
- Ping statistics for 192.168.3.2:
- Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 0ms, Maximum = 1ms, Average = 0ms
2 案例2:配置trunk中繼鏈路
2.1 問題
在兩台交換機上分別創建vlan2、vlan3,參照如下網絡拓撲圖-4將端口加入到指定的vlan並配置IP址,實現跨交換機的同vlan主機的通信。

圖-4
2.2 方案
分別在sw1和sw2上創建vlan2和vlan3並把相應的接口划分到對應的vlan並為客戶端配置IP地址,IP地址具有唯一性所以同一局域網絡中不能存在相同的IP,另所有的接口默認為vlan1,所以不配置trunk中繼鏈路vlan1也是可以跨交換機通信的。
2.3 步驟
實現此案例需要按照如下步驟進行
步驟一:為客戶端配置IP,分別為交換機sw1和sw2創建vlan並把相應的接口划到相對應的vlan下
1)參照圖-4為客戶端分別配置相對應網段的IP
2)為交換機創建vlan2、vlan3 並把相應的接口划到vlan下
- Switch >enable
- Switch#configure terminal
- Switch(config)#hostname SW1
- SW1 (config)#Switch(config-vlan)#exit
- SW1 (config)#vlan 3
- SW1 (config-vlan)#exit
- SW1 (config)#interface fastEthernet 0/3
- SW1 (config-if)#switchport access vlan 2
- SW1 (config-if)#exit
- SW1 (config)#interface fastEthernet 0/4
- SW1 (config-if)#switchport access vlan 2
- SW1 (config-if)#exit
- SW1 (config)#interface fastEthernet 0/5
- SW1 (config-if)#switchport access vlan 3
- SW1 (config-if)#exit
- SW1 (config)#interface fastEthernet 0/6
- SW1 (config-if)#switchport access vlan 3
- Switch >enable
- Switch#configure terminal
- Enter configuration commands, one per line. End with CNTL/Z.
- Switch(config)#hostname SW2
- SW2 (config)#Switch(config-vlan)#exit
- SW2 (config)#vlan 3
- SW2 (config-vlan)#exit
- SW2 (config)#interface fastEthernet 0/3
- SW2(config-if)#switchport access vlan 2
- SW2 (config-if)#exit
- SW2 (config)#interface fastEthernet 0/4
- SW2 (config-if)#switchport access vlan 2
- SW2 (config-if)#exit
- SW2 (config)#interface fastEthernet 0/5
- SW2 (config-if)#switchport access vlan 3
- SW2 (config-if)#exit
- SW2 (config)#interface fastEthernet 0/6
- SW2 (config-if)#switchport access vlan 3
3)分別查看SW1和SW2交換機上的vlan信息
- SW1#show vlan
- VLAN Name Status Ports
- ---- -------------------------------- --------- -------------------------------
- 1 default active Fa0/1, Fa0/2, Fa0/8, Fa0/9
- Fa0/10, Fa0/11, Fa0/12, Fa0/13
- Fa0/14, Fa0/15, Fa0/16, Fa0/17
- Fa0/18, Fa0/19, Fa0/20, Fa0/21
- Fa0/22, Fa0/23, Fa0/24
- 2 VLAN0002 active Fa0/3, Fa0/4
- 3 VLAN0003 active Fa0/5, Fa0/6
- 1002 fddi-default act/unsup
- 1003 token-ring-default act/unsup
- 1004 fddinet-default act/unsup
- 1005 trnet-default act/unsup
- VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
- ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
- 1 enet 100001 1500 - - - - - 0 0
- 2 enet 100002 1500 - - - - - 0 0
- 3 enet 100003 1500 - - - - - 0 0
- 1002 fddi 101002 1500 - - - - - 0 0
- 1003 tr 101003 1500 - - - - - 0 0
- 1004 fdnet 101004 1500 - - - ieee - 0 0
- 1005 trnet 101005 1500 - - - ibm - 0 0
- Remote SPAN VLANs
- ------------------------------------------------------------------------------
- Primary Secondary Type Ports
- ------- --------- ----------------- ------------------------------------------
- SW1#
- SW2#show vlan
- VLAN Name Status Ports
- ---- -------------------------------- --------- -------------------------------
- 1 default active Fa0/1, Fa0/2, Fa0/8, Fa0/9
- Fa0/10, Fa0/11, Fa0/12, Fa0/13
- Fa0/14, Fa0/15, Fa0/16, Fa0/17
- Fa0/18, Fa0/19, Fa0/20, Fa0/21
- Fa0/22, Fa0/23, Fa0/24
- 2 VLAN0002 active Fa0/3, Fa0/4
- 3 VLAN0003 active Fa0/5, Fa0/6
- 1002 fddi-default act/unsup
- 1003 token-ring-default act/unsup
- 1004 fddinet-default act/unsup
- 1005 trnet-default act/unsup
- VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
- ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
- 1 enet 100001 1500 - - - - - 0 0
- 2 enet 100002 1500 - - - - - 0 0
- 3 enet 100003 1500 - - - - - 0 0
- 1002 fddi 101002 1500 - - - - - 0 0
- 1003 tr 101003 1500 - - - - - 0 0
- 1004 fdnet 101004 1500 - - - ieee - 0 0
- 1005 trnet 101005 1500 - - - ibm - 0 0
- Remote SPAN VLANs
- ------------------------------------------------------------------------------
- Primary Secondary Type Ports
- ------- --------- ----------------- ------------------------------------------
- SW2#
步驟二:為交換機配置trunk中繼鏈接路
1)分別進入兩台交換機相連接的f0/7接口配置trunk中繼鏈路
- SW1>enable
- SW1#configure terminal
- SW1(config)#interface fastEthernet 0/7
- SW1(config-if)#switchport mode trunk
- SW2#enable
- SW2#configure terminal
- SW2(config)#interface fastEthernet 0/7
- SW2(config-if)#switchport mode trunk
- SW2(config-if)#
2)測試2.0網段和3.0網段跨交換機通信
- PC>ping 192.168.2.3
- Pinging 192.168.2.3 with 32 bytes of data:
- Reply from 192.168.2.3: bytes=32 time=1ms TTL=128
- Reply from 192.168.2.3: bytes=32 time=0ms TTL=128
- Reply from 192.168.2.3: bytes=32 time=0ms TTL=128
- Reply from 192.168.2.3: bytes=32 time=0ms TTL=128
- Ping statistics for 192.168.2.3:
- Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 0ms, Maximum = 1ms, Average = 0ms
- PC>ping 192.168.3.3
- Pinging 192.168.3.3 with 32 bytes of data:
- Reply from 192.168.3.3: bytes=32 time=1ms TTL=128
- Reply from 192.168.3.3: bytes=32 time=0ms TTL=128
- Reply from 192.168.3.3: bytes=32 time=0ms TTL=128
- Reply from 192.168.3.3: bytes=32 time=0ms TTL=128
- Ping statistics for 192.168.3.3:
- Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
- Approximate round trip times in milli-seconds:
- Minimum = 0ms, Maximum = 1ms, Average = 0ms
3 案例3:以太通道配置
3.1 問題
企業需要增加帶寬和網絡可用性,以太通道可以同時滿足這兩個條件,而又無需購買新設備。
3.2 方案
在某些環境下,為了在現有條件下增加帶寬而不增加額外的設備,以太通道是可用技術之一。以太通道為交換機提供了端口捆綁的技術,允許兩個交換機之間通過兩個或多個端口並行連接,同時傳輸數據,以提供更高的帶寬。
企業網絡模擬拓撲環境如圖-5所示:

圖-5
3.3 步驟
實現此案例需要按照如下步驟進行。
步驟一:在交換機A上分別配置以太通道
太通道的配置模式與Trunk類似,也有開啟、企望等。同樣的,在生產環境下都是強制設置以太通道處於on的狀態,而不是讓它們自動協商。
- sw1(config)# interface range fastEthernet 0/7 – 9
- Switch(config-if-range)#switchport mode trunk
- sw1(config-if-range)#channel-group 1 mode on
- sw1(config-if-range)#
步驟二:在交換機B上分別配置以太通道
- sw2(config)# interface range fastEthernet 0/7 – 9
- Switch(config-if-range)#switchport mode trunk
- sw2(config-if-range)#channel-group 1 mode on
- sw2(config-if-range)#
步驟三:在交換機A上查看以太通通道配置
- sw1# show etherchannel 1 summary
- Flags: D - down P - in port-channel
- I - stand-alone s - suspended
- H - Hot-standby (LACP only)
- R - Layer3 S - Layer2
- U - in use f - failed to allocate aggregator
- u - unsuitable for bundling
- w - waiting to be aggregated
- d - default port
- Number of channel-groups in use: 1
- Number of aggregators: 1
- Group Port-channel Protocol Ports
- ------+-------------+-----------+---------------------------------
- 1 Po1(SU) - Fa0/7(P) Fa0/8(P) Fa0/9(P)
根據輸出最后一行小括號中的提示,可以獲知以太通道是二層的(S)、正在被使用的(U),端口Fa0/7、Fa0/8和Fa09在以太通道中(P)。
步驟四:創建以太通道后,系統會增加一個名稱為Port-channel 1的端口,可以通過show running-config命令查看到其信息
- sw2#show running-config
- Building configuration...
- Current configuration : 1308 bytes
- !
- version 12.2
- no service timestamps log datetime msec
- no service timestamps debug datetime msec
- no service password-encryption
- !
- hostname tarena-sw2
- !
- !
- .. ..
- interface Port-channel 1 //以太通道信息
- switchport mode trunk
- !
- .. ..
4 案例4:DHCP服務配置
4.1 問題
大型企業網絡客戶機數量較多,客記機IP地址配置如果都為靜態配置存在如下問題:
- 增加網絡管理員工作量
- 靜態手動配置容易輸入錯誤
- 靜態手動配置容易沖突
4.2 方案
在路由器上配置DHCP服務為客戶端自動分配IP地址如圖-6所示:

圖-6
- VLAN 1:192.168.1.0/24
- 網關192.168.1.254
- 首選DNS為202.106.0.20
- 預留IP地址打印服務器:192.168.1.1
- 預留IP地址文件服務器:192.168.1.100
4.3 步驟
實現此案例需要按照如下步驟進行。
步驟一:路由器R1配置DHCP服務
1)配置路由器接口IP
- R1(config)#interface fastEthernet 0/0
- R1(config-if)#ip address 192.168.1.254 255.255.255.0
- R1(config-if)#no shutdown
2)DHCP服務配置
- R1(config)#ip dhcp pool vlan11)
- R1(dhcp-config)#network 192.168.1.0 255.255.255.0
- R1(dhcp-config)#default-router 192.168.1.254
- R1(dhcp-config)#dns-server 202.106.0.20
- R1(config)#ip dhcp excluded-address 192.168.1.1
- R1(config)#ip dhcp excluded-address 192.168.1.100
3)設置主機A的IP配置為自動獲取如圖-7所示:
