08-11-2010 11:18 PM - edited 03-06-2019 12:26 PM
Hello
If I configure catalyst 3560 like this:
interface fa0/1
switchport mode access
switchport access vlan 1
interface fa0/2
switchport mode access
switchport access vlan 2
interface fa0/3
switchport mode access
switchport access vlan 3
interface fa0/22
switchport mode trunk
switchport trunk encapsulation dot1q
switchport trunk allowed vlan add 1-10
interface fa0/23
switchport access vlan 312
switchport mode dot1q-tunnel
interface fa0/24
switchport mode trunk
switchport trunk encapsulation dot1q
switchport trunk allowed vlan add 312
and then connect port 22 and 23 with patch-cord, will traffic on port 24 be Q-in-Q incapsulated?
Solved! Go to Solution.
08-11-2010 11:25 PM
Hi Alexandr,
I am not sure why you want to do it like this but that should work. The packest leaving port 24 should have 2 tags, External 312 and Internal (1-10).
JayaKrishna
08-12-2010 04:40 AM
Hi Alexandr,
You config should work. We have the same config in our network working fine without any issues.
HTH
Arun
08-17-2010 12:12 PM
I think with some of the later code this works on the 3560/3750.
A few years ago I saw some issues with it when double tagged frames come into the switch with dest mac and IP of the switch...I think we were trying to telnet to it from a device across the tunnel. Instead of switching the traffic out again to a tunnel to decap it, we instead were sending it directly to the CPU...which couldn't understand the frame due to the doubletagging, and dropped it.
The soultion worked for traffic going through the switch, but ultimatly some managment issue were the only pain point from across the tunnel...now I'm not sure if that problem still exists. Just something to keep an eye on.
I'm pretty sure a co-worker of mine tested this again recently and didn't encounter the issue I saw a few years ago. I didnt get a chance to look at his setup, but looks like it may work like you'd expect now.
08-11-2010 11:25 PM
Hi Alexandr,
I am not sure why you want to do it like this but that should work. The packest leaving port 24 should have 2 tags, External 312 and Internal (1-10).
JayaKrishna
08-12-2010 04:02 AM
I am not sure why you want to do it like this
Because I don't want to buy two switches, when enough only one
You can look at pictures of my network config here:
08-12-2010 04:40 AM
Hi Alexandr,
You config should work. We have the same config in our network working fine without any issues.
HTH
Arun
01-17-2020 11:39 PM
Good Day everyone,
I worked for an ISP but presently the network runs on L2 with one point (FW) that does all the routing..and switches cannot support QinQ. A customer is requesting for just L2VPN...I am asking for what type of cisco switch that support Q in Q and how can these be integrated with the exjsting platform...
08-12-2010 04:57 AM
Sorry ...wrong question
08-17-2010 12:12 PM
I think with some of the later code this works on the 3560/3750.
A few years ago I saw some issues with it when double tagged frames come into the switch with dest mac and IP of the switch...I think we were trying to telnet to it from a device across the tunnel. Instead of switching the traffic out again to a tunnel to decap it, we instead were sending it directly to the CPU...which couldn't understand the frame due to the doubletagging, and dropped it.
The soultion worked for traffic going through the switch, but ultimatly some managment issue were the only pain point from across the tunnel...now I'm not sure if that problem still exists. Just something to keep an eye on.
I'm pretty sure a co-worker of mine tested this again recently and didn't encounter the issue I saw a few years ago. I didnt get a chance to look at his setup, but looks like it may work like you'd expect now.
08-21-2010 05:53 AM
Many thanks to all!
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide