VLAN Inroduction

VLAN or virtual LAN is used to separate broadcast domain virtually. In some design case, VLAN is used to group user and set the policy for each group. Users in the same VLAN, they can communicate with each other without routing even if they are not located physically on the same LAN segment. 

The traffic from one VLAN to another VLAN must be routed. So we can set routing policy or firewall policy differently for specific VLAN.

VLAN Type

  • VLAN 1 is a system default VLAN, you can use this VLAN but you cannot delete it. By default VLAN 1 is use for every port on the switch. 
  • Standard VLAN range from 2-1001 you can create your own VLAN in this range, you also can delete these VLANs. 
  • Standard VLAN range from 1002-1005 it’s Cisco default for FDDI and Token Ring. You cannot delete VLANs 1002-1005. mostly we don’t use VLAN in this range.
  • Extended VLAN range from 1006-4094 not all VLAN in this range can use some are reserved for internal usage.  It’s a kind of backend process to create this VLAN for internal application.  One potential problem is that VLAN created for internal applicate is not standard it’s different base on platform or version. Extended VLANs are not propagate by VTP version 1 & 2. so mostly we use extended VLAN in two case when we are using transparent mode or we configure VTP version3.

Implement on cisco:
sw1#conf t
sw1(config)#vlan 10
sw1(config-vlan)#name "Creative & Design"

Verification:
sw1#show vlan

VLAN Name                             Status    Ports

—- ——————————– ——— ——————————-

1    default                          active    Et0/1, Et0/2,

10   "Creative & Design"              active    

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   

10   enet  100010     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   

 

Primary Secondary Type              Ports

——- ——— —————– ——————————————

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