"vlan-id dot1q" command

[kunihiko.fujii]

Can anyone please advise how "vlan-id dot1q" command works?

According to the Command lookup tool, it says "This command allows you to enable IEEE 802.1Q VLAN encapsulation for a  specific VLAN on an Ethernet interface without associating the VLAN with  a subinterface."

Does this mean when I configure "vlan-id dot1q (vlan-id)" on a Ethernet interface, frame sent out the interface wil be tagged with specified vlan-id?

Also I want to know how router in other end should be configured as dot1q trunk.

I did test this command using configuration below, but it did not work (cannot ping each other)

Assume Router1 Fa0/1 is directly connected to Router2 Fa0/1

Router1

interface Fastethernet 0/1

  ip address 192.168.1.1 255.255.255.252

  speed 100

  duplex full

  vlan-id dot1q 55

Router2

interface Fastethernet0/1

  speed 100

  duplex full

!

interface Fastethernet0/1.55

  encapsulation dot1q 55

  ip address 192.168.1.2. 255.255.255.252

!

Thanks!

[ubuntuer0424]

according the command line tool,i think the words "specific" is important! This means some services in a VLAN,eg.pppoe and brigde-group not be configured on a single subinterface,that is so inneccesary.This VLAN is so called "specific".Now vlan-id command can direct to tagging a vlan in main interface mode .Is it convienent?

[Iloveyou]

I dont understand the comment above

[Gopinath_Pigili]

Hello,

• In the router subinterface mode, we can link the VLAN ID to this interface as well as assign it an ip address and a subnet mask.
•  Use the encapsulation dot1q vlan_id command in subinterface configuration mode to enable 802.1Q and associate one specific VLAN with the subinterface.
• Each subinterface configuration lists two subcommands. One command (encapsulation) enables trunking and defines the VLAN whose frames are considered to be coming in and out of the subinterface.
• The ip address command works the same way it does on any other interface.

Best regards
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[Iloveyou]

This means some services in a VLAN,eg.pppoe and brigde-group not be configured on a single subinterface,that is so inneccesary.

I don't understand this sentences