voice vlan issue

[CATYO]

Hi there.

I have a question about voice vlan.

I have one switch in my office and need to extend the port for extension of office. but there's a ristrict. I can't change the config with existing switch.

I'm planning to buy one or two switches. and use existing port on sw1 as uplink. (but uplink remains access port with voice vlan / data vlan)

So i think this way to extend the ports.

What do you think? is it working prorely ?? I can't cahnge the access mode to trunk mode on the existing switch because of ristrict.

and Between SW1 and SW3, there is vlan mismatch so i will disable CDP.

does it make any problem ?

please correct me if there are some problems

Thank you :  )

[Chris Deren]

So, it looks like you only want vlan 101 extended to SW2, and 102 to SW3.  If that is the case you need to put the interfaces on SW1 in appropriate access VLANs. int fa0/2 on SW1 need to have "switch port access vlan 102". Alternatively you can create trunks between the switches and thus allow all VLANs on all switches.

[CATYO]

Thank you : )

As I mentioned, I can't handle SW1. It is customer ristrict (i don't know why).

SO you mean, I can set the port between SW1 and SW2 as trunk port and SW1's port remained access vlan and voice vlan SW1 and SW3 as well.

is there any issue with this ?? what about CDP ?

Do i need to disable CDP on SW2, SW3?

[Dennis Mink]

well, your SW1 is obviously the restricting factor,  which means, you can't extend vlan 102 to SW2 and 3. its  that simple.

CDP, dont worry about that, you can leave it on or off. It has no effect on your VLANs.

which means you will need to run your phones and PC's in VLAN 101.

Still dude, bad design. 

[CATYO]

Oh i see...

I agree it is absolutely bad degisn . But there are some reasons, and they have to extend port density with this restrict.

What about configuring switch voice vlan 102 instead of swi acc vlan 101 on SW3? Can i extend vlan 102 which is for voice vlan ?

I 'm concerned about VLAN 101, 102 has different subnet. can i  run phones, PC in same VLAN 101?

[Dennis Mink]

Yeah, nah, you can't  trick sw3 by configuring vlan 102 on its fa0/24. switch 1 will not honor that, as that only works if there is a phone connected to Fa0/2 on switch 1.

You are flogging a dead horse mate!

[CATYO]

Thanks for your prompt reply.

Can you explain more detail ?

I think when sw3 got the frame from the phone, sw3 will tag it as vlan 102. Am i right?

Then, sw3 forwarding it via fa0/24 with vlan 102 because fa0/24 is configured as access vlan 102 ... and sw1 can know this is vlan 102 data and this is for voice.

Is there any problem with this process?

please correct me. I'm still confusing. -_-;;

[Dennis Mink]

You will have a problem on port fa0/2 on SW1 if you do it this way.as both end will have be a member of a different VLAN

Better to get access to SW1 (do a password recovery) and create trunk between the switches.  

[CATYO]

Thank you : )

As I mentioned, I can't handle SW1. It is customer ristrict (i don't know why).

what if i configure SW2, SW3's uplink as trunk mode(dot1q).

Is it working ??