Solved: VLANs Spanning Access Layer Switches

ITSNJEDARK · ‎12-19-2009

First post, take it easy on me if it's not in the right place...

All documentation I read advises not to have a VLAN span across more than one Access layer switch, and they always add the *if possible to the end of that statement. My question is, what about your voice vlan? Doesn't that need to span across all of your access layer switches so you can connected all your phones?

I would really appreciate any insight on this topic as I'm currently planning a new network design that will use the traditional L2 Access layer and L3 Distro.

Thanks!

Jon Marshall · ‎12-19-2009

ITSNJEDARK wrote:

First post, take it easy on me if it's not in the right place...

All documentation I read advises not to have a VLAN span across more than one Access layer switch, and they always add the *if possible to the end of that statement. My question is, what about your voice vlan? Doesn't that need to span across all of your access layer switches so you can connected all your phones?

I would really appreciate any insight on this topic as I'm currently planning a new network design that will use the traditional L2 Access layer and L3 Distro.

Thanks!

You don't have to have just one voice vlan for the entire network. So each access-layer switch could have one data vlan and one voice vlan each which are contained only on that switch. So you can have as many voice vlans as data vlans. if you are going with a traditional L2 access-layer it helps if you can keep vlans on each switch but it wouldn't be a disaster if you didn't. Many L2 access-layer networks have vlans that span across multiple switches.

Jon

View solution in original post

Jon Marshall · ‎12-19-2009

ITSNJEDARK wrote:

First post, take it easy on me if it's not in the right place...

All documentation I read advises not to have a VLAN span across more than one Access layer switch, and they always add the *if possible to the end of that statement. My question is, what about your voice vlan? Doesn't that need to span across all of your access layer switches so you can connected all your phones?

I would really appreciate any insight on this topic as I'm currently planning a new network design that will use the traditional L2 Access layer and L3 Distro.

Thanks!

You don't have to have just one voice vlan for the entire network. So each access-layer switch could have one data vlan and one voice vlan each which are contained only on that switch. So you can have as many voice vlans as data vlans. if you are going with a traditional L2 access-layer it helps if you can keep vlans on each switch but it wouldn't be a disaster if you didn't. Many L2 access-layer networks have vlans that span across multiple switches.

Jon

ITSNJEDARK · ‎12-19-2009

Thanks Jon. That's what I was hoping to hear. It will be a small network (about 8 3560-E access switches). All the other voice networks I've seen had one voice vlan, so I just assumed it was a Cisco standard practice. I will continue to read all Cisco's design guides to hopefully put together a rock solid solution, but you're insight makes me feel alot better.

Thanks again!

Ray