Q-In-Q using M7i and CISCO Switch

sthaug at nethelp.no sthaug at nethelp.no
Wed Sep 1 06:34:55 UTC 2010

> We have a client with the following situation:
>                                                              v1, v2, v3
>   -------| Switch | ----------| Switch |----------------| 
> Switch|------------- JUNIPER M7i IQ2E -----
> Carrier offers only 3 vlans to the client.  But he wants to push some 
> more vlans inside the 3 ones.
> It is possible to initiate and finish Q-In-Q vlans using a cisco ME 
> switch and a JUNIPER M7i with IQ2E interface ?
> The following link shows stack configuration. It can be used to do 
> Q-In-Q with this situation  ?
> http://www.juniper.com.lv/techpubs/en_US/junos10.0/information-products/topic-collections/config-guide-network-interfaces/id-12155750.html 
> Someone tries to configure it any time ?

You need to differentiate between *terminating* a dual tagged VLAN, and
the operation of pushing/popping a VLAN tag. M7i with IQ2E kan do either.

Note that you are *not* guaranteed that a carrier which offers a VLAN
transport service will automatically handle dual tagged VLANs - this must
be verified. Note also the obvious MTU implication of a 4 byte additional
VLAN tag.

You might be better off discussing this on the juniper-nsp list.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no

More information about the NANOG mailing list