Connecting Cisco to HP

[David Newberger]

Hello All,

I am trying to get 6 Cisco 3550 switches to play nice with the HP 5412zl I just got. I can't seem to get them to communicate with each other. I also have 3 Vlans. I would assume that

On HP 5412zl
A1,A3,A5,A7,A9,A11
would be untagged Vlan 10
and Tagged vlan 2 and 3

On the Cisco 3550's

Fa0/24
Trunked Vlan 10 with 802.1q tagging.

is this correct?

[Matt Hobbs]

Have a read of this: http://www.tecnocael.it/ftp/docs/ProCurve_Cisco.pdf

On a Cisco the 'native' VLAN (usually 1) is untagged, the rest are all tagged. So on a ProCurve, leave VLAN 1 untagged, and tag the rest.

[André Beck]

David,

Matt already told you about the magic of tagging (Default VLAN untagged, all others tagged is actually the door into multi vendor compatibility with more then just Cisco, but there are exceptions). The additional thing to keep in mind when connecting Cisco and ProCurve tagged links is the Spanning Tree implementation. Cisco uses per-VLAN spanning tree by default, while HP has STP disabled by default (bad idea) and if enabled, they support either Single (R)STP or MSTP. There are issues when coupling these directly to Cisco (Rapid) PVST+. The only way to get it compatible through both platforms would be to run MSTP on the Catalysts, too.

Or get all this out of the way and connect on L3 (3550s allow for routed interfaces, the zl ProCurves will need dedicated VLANs with SVIs but given the peer is a routed interface, you could leave out the BPDU filter).

HTH,
Andre.