Saturday, February 26, 2011

Dell PowerConnect VLAN Interoperability with Cisco

According to this document, Cisco catalyst switches and Dell PowerConnect switches (in fact, most other non-Cisco switches e.g. Juniper etc) are not compatible on VLAN trunking i.e. single physical link that carries multiple VLANs. This is because Dell and Cisco devices have different default mechanisms for dynamic exchange of VLAN information. Cisco Catalyst switches’ default mechanism is the VLAN trunking protocol(VTP). In contrast, Dell PowerConnect switches use the GARP VLAN registration protocol (GVRP) for dynamic exchange of VLAN configuration information. Because the Dell and Cisco switches use different protocols by default, no exchange of VLAN control traffic will take place – and thus no intra-VLAN traffic will flow between the Dell and Cisco switches. By disabling VTP and enabling GVRP on the Cisco switch, it is possible to exchange intra-VLAN data and control information in mixed Dell-Cisco environments.

I have just recieved confirmation from Cisco saying this:

Unfortunately, GVRP is not supported on Catalyst 3560 or 3750 switches. GVRP is only supported on the CatOS releases on Cat4000 and Cat6500 platfroms (on select releases - Only 6000s, 5000s and 4000 switches running CatOS software support this feature.)

If you connect a 3560 or 3750 switch to a device that supports GVRP you will see unsupported messages on the switch, telling you that the device itself is not able to process the GVRP information from the hosts/neighbours and therefore it drop it.

Nevertheless, GVRP is supported on IOS Router (cGVRP):
What's the hell?! CatOS is already obsolete. And IOS routers being at L3 do not even need to pass VLAN trunking information. Does it mean Cisco lock-in?


  1. Whats more is that I have a mixed bag of Cisco switches that don't all talk to each other right out of the box. Case in point, the 3560G and the SG300-10. 3560G is an impeccable switch and the 300-10 is pretty darn useful as well - labled as a "Small Business" switch. None the less, the 3560G talks VTP and the 300-10 (which is brand new no less, talks GVRP. What the hell is right!

  2. I remember this, and i was asking the same question in that time.