Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

q in q tunnels

Hi all

I currently have the current setup

DMZ switch > Dist switch > WAN > Dist switch > DMZ switch

So basically the DMZ switch plugs into the dist switch, from this dist switch is a ethernet wan connection, which plugs into a dist switch on the remote site, then on that dist switch the dmz switch also plugs in.

We have dot1q tunneling setup so that dmz traffic tunnels over the WAN to the other dmz switch.

My question is

If I then move the WAN connection to another switch, so the tunnel connection is no longer on the same switch as the WAN, will it still work providing I tag the tunnel access vlan to the other switch ?

cheers

Carl

1 REPLY
Cisco Employee

q in q tunnels

Hi Carl,

If this issue is still relevant, can you please clarify the following statement?

If I then move the WAN connection to another switch, so the tunnel  connection is no longer on the same switch as the WAN, will it still  work providing I tag the tunnel access vlan to the other switch ?

Are you suggesting that currently, the switchport mode dot1q-tunnel is configured on your Dist switch, and you plan to move the WAN connection from this WAN switch simply to a different switch?

If I got this right then moving the WAN connection to a different switch should not create any connectivity issues, provided that the VLAN into which the WAN connection was originally placed into stays the same. One thing to watch out, though: you should take care to increase the system MTU on your switches to 1504B to accomodate for the additional tag that the frame carries. Otherwise, some of your frames may get dropped. Be aware that changing the system MTU may also impact OSPF, IS-IS and other adjacencies so while this change is necessary, it has to be performed carefully.

Best regards,

Peter

166
Views
0
Helpful
1
Replies