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microfeel
Beginner

How many VLAN possible to assign to a router port

For example I have a border router with two ports, first port is wan port and another port is lan port.

How many VLANs possible to assign to a router port?

1 ACCEPTED SOLUTION

Accepted Solutions

Hi Bot,

I am not sure for what purpose this designed was represented.

They could have just directly terminted the ISP to router then followed by switch will solve the purpose.

HTH

Regards

Inayath

View solution in original post

6 REPLIES 6
InayathUlla Sharieff
Cisco Employee

Hi Bot,

Sorry if I have misunderstood your question. As far my knowledge you cannot assign the vlans on the router.

We use the concept of intervlan routing or router on a stick.

More details on https://supportforums.cisco.com/thread/2048618

Vlan on Router:

A vlan configuration on a router is slightly different than on a switch.  On a switch, you would create the vlan and then the routed vlan interface.

On a router you tie a vlan to a subinterface.  You need to create the subinterface and then do the encapsulation dot1q command.  This command basically assigned the vlan to the subinterface.  In this example, there are 2 vlans, vlan 100 and 201.  On the eth 0/0 interface, I created two subinterfaces.  fastethernet0/0.100 and f0/0.201.  Notice that I matched the subinterface number with the vlan ID.  You do not have to do this, but it is a best practice and really helps you as the administrator keep things organized.  So, under f0/0.100, there is the encapsulation dot1q 100, which basically binds vlan 100 to subinterface f0/0.100, then I assigned the IP.  The same is for the other subinterface.  So the router is trunking two vlans on its f0/0 interface, vlan's 100 and 201.

interface FastEthernet0/0
no ip address
speed 100
full-duplex
!
interface FastEthernet0/0.100
description test Network
encapsulation dot1Q 100
ip address 192.168.102.1 255.255.255.128
no snmp trap link-status
!
interface FastEthernet0/0.201
description  Office
encapsulation dot1Q 201
ip address 205.127.102.129 255.255.255.128
no snmp trap link-status


Please feel free to provide some more details on what exactly you are looking if the above link doenst solve your purpose.

HTH

REgards

Inayath

*Plz rate all usefull posts.

Hi Inayath,

I understud from your words there is hardware restriction.

Is there another restriction for VLAN assignments to a router ports?

Hi Bot,

I dont see any restriction for vlan assignments to a router ports.

HTH

Regards

Inayath

Hi Inayath,

I saw a design of network like  below

ISP <--> [fastethernet0/1]SWITCH1[fastethernet0/2]<--> ROUTER<--> SWITCH2

When I asked about the SWITCH1 purpose on the scheme I was told the purpose of the SWITCH1 to terminate VLANs.

So why I asked that question.

Regards

Bot

Hi Bot,

I am not sure for what purpose this designed was represented.

They could have just directly terminted the ISP to router then followed by switch will solve the purpose.

HTH

Regards

Inayath

View solution in original post

Ravi Singh
Rising star

Hello Bot,

It's totally depends upon sub interfaces which you can create for a particular port. because you can assign one interface to one VLan at one time.