does router support vlan ???

[Dr.X]

Coincidencely when i tried to configure router 877 as an adsl router i found that a vlan configuration is included. my question is what is the benefit of using vlans in router ??? i studied that we use it in switches for the purpose of network enhancment from broadcasts and  netwrok segmentation.

My question is in general , why we use vlans in routers ?

thansk alot

[ebarticel]

Switches works at layer 1 and 2 in general, and routers work at layer 1,2, and 3. To be able to work at layer 2 it needs some features found in switches, and one of that feature is the possibility of creating vlans.

Also routers sometime are used in "router-on-the-stick" implementation where it helps with interVlan communication which a layer 2 switch can not do.

Hope this helps

Eugen

[cadet alain]

Hi,

I would add to Eugen reply that some routers also got an integrated switch or can have a switch module added and so vlans can be configured for the configuration of this switch.

Regards.

Alain

[Richard Burts · Accepted solution]

And when you look at the data sheet for the 870 products it clearly states that the 877 router includes a 4 port switch. See this URL for details:

http://www.cisco.com/en/US/prod/collateral/routers/ps380/ps6200/product_data_sheet0900aecd8028a976.html

So the VLAN referred to in the original post is clearly part of the 4 port switch included in the router.

HTH

Rick

[Dr.X]

Hi,

i would like to thank you all, you really exactly gave me what i want .

[Leo Laohoo]

The 877 has a 4-port Layer 2, switch and support MDI/MDI-X.

If your 877 is running 12.4 & 15.X IOS, it will support 2 VLANs (including VLAN 1).  If you want up to 10 VLAN support, the you need to downgrade to IOS version 12.3.

[johnlloyd_13]

nice one leo +5

didn't know 877 need a downgrade to have 10 VLANs. seems odd to me. thought it was the reverse.

[Leo Laohoo]

didn't know 877 need a downgrade to have 10 VLANs. seems odd to me. thought it was the reverse.

Me too.  Imagine my surprise when I learnt that too.  Tried it and, yes, at 12.3 you configure 10 VLANs but at 12.4 and 15.X you can only add one more VLAN.

I don't know what is the insane logic behind this.

[Dr.X]

you also surprised me  ,,,,, what is the benefit of using 10 vlans if actually i have only 4 ethenet interfaces ???

[Leo Laohoo]

Doesn't mean just because you have 4 interfaces you can't connect either one to a switch.