6509 - Double tag a vlan?

rschmid01 · ‎05-12-2016

I manage a 6509 with a SUP 720 3 (MSFC3) running 15.1(2)SY7.

There is a single Ten Gig interface (WS-X6704-10GE) to a network provider, using trunked vlans to IP route to 3 other 6509 routers.

I now need to send an additional vlan to one of those 6509 routers over one of those network provider vlans (132). My goal is to double-tag the 132 vlan to send both our IP vlan, and the new customer vlan to the remote router. After days of searching, and 2 failed maintenance windows, I think the 6509 is not cable of this. Am I wrong?

First, I have tried vlan stacking with "encapsulation dot1q second-dot1q" but this command is not accepted on the ten gig sub interface. Then I read that the 6500 uses 802.1Q tunnels on interfaces to carry double-tagged 802.1Q-in-Q traffic.

However, this configuration using "switchport vlan mapping [vlan-id] dot1q-tunnel outer [vlan-id]" also does not work.

Then, I read that I need an ES card, which, is not exactly cheap. The datasheet of the ES does mention 'IEEE 802.1q encapsulations', but I am still not confident this will solve our problem.

Should I replace the 6509? Should I insert an extreme switch with a 10 gig card in between? Or purchase the ES card and pray it works?

I value your feedback and hope there is an obvious answer that I am not seeing.

-Ryan

Iulian Vaideanu · ‎05-13-2016

Hi Ryan,

Please correct me if I misunderstood your setup: you currently trunk three vlans (let's say 130,131,132) over that single 10G link, and you want 132 to be the outer tag for two other vlans (let's say 10,20 - I'm assuming the end-point router is no concern, it'll know what to do with those double tags).

If that's the case, you could physically loop two other ports in your 6509 (10G, or even 1G if there won't be too much traffic on vlan 132) - one port configured as "switchport mode trunk / switchport trunk allowed vlan 10,20" and the other configured as "switchport mode dot1q-tunnel / switchport access vlan 132".

If later on you need to do the same for another vlan (say 131) you'll need another pair of ports, and so on... we're using a C4500X for this purpose (selective q-in-q / multiple "switchport vlan mapping <inner-tag> dot1q-tunnel <outer-tag>").