Using more then 4096 VLAN's. Q-in-Q ?

Basically, we are creating a network of customers, which we all want to give a seperate VLAN. The customer base will definitly exceed the 4096 VLAN's which is the maximum in the 802.1q specification.

Right now, i'm looking into Q-in-Q tunneling, to increase the number of VLAN's possible. My question: Is it possible to configure more than 4096 VLAN's like this on the same router (Cisco 3560), or didn't i understand Q-in-Q correctly?

If it is possible, can somebody post some configuration snippets or URL's?


Remco Bressers

Reply to
R. Bressers
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Yes, but it's hard and I do not know if the IOS supports that many interfaces. (Ignoring mass PPPoE configurations without explicit vlan subinterfaces.)

Yes. Every vlan-cabable system will remove or add only one level of vlan tags. So your router can only handle those Q-in-Q if there is only one level of Q. You need a switch to remove the outer level of tags and forward them to a router port which supports usual VLAN. You can do this multiple time for each outer tag and get multiple routers with a single trunk port connected to this switch.

You can even try to use X-cable between to neighboured ports. But be careful to not reuse the same vlan number (outer or inner) on the chassis without explicitly preventing bridging! The 35xx is difficult in this subject!

Reply to
Lutz Donnerhacke

Let's assume 1 piece of hardware (the 3560) is capable of terminating one Q-in-Q tunnel AND capable of configuring the seperate VLAN's in one.

Can anyone verify if this is really (im)possible?

If it is, is there any example configuration on the net somewhere?


Reply to
R. Bressers

Don't do this.

It is possible. I wrote this. I did this.

From the brain...

interface f0/1 no switchport no ip address switchport mode trunk switchport enc dot1q desc Trunkport for outer vlan 10 ! interface f0/1.2 encap dot1q 2 desc VLAN2 ! interface f0/10 switchport mode dot1qindot1q -- access without checking switchport access vlan 10 desc Map vlans to outer vlan 10 ! interface f0/20 switchport mode trunk switchport trunk allow vlan 10 -- filter out inner vlans desc Q-in-Q port !

Use a cross cable to connect f0/10 and f0/1. Never reuse the same vlan id on the same chassis for different scopes!

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