Switches, Hubs, and Modems
cancel
Showing results for 
Search instead for 
Did you mean: 

ProCurve 2810 and Cisco switches

gesadmin
Advisor

ProCurve 2810 and Cisco switches

I am driving myself mad trying to get MST to work with PVST+. I've got two ProCurve 2810-48Gs and a single Cisco 3550 set up in a triangle configuration. On the Cisco I've got VLAN1,10,24,and 27. On the HPs I've got VLAN1,24, and 27 configured. A single MST region with two MSTI's have been configured on the HPs (not counting the IST). One MSTI has VLAN24 (priority 1) and VLAN27 (priority 2) on one HP switch and VLAN24 (priority 2) and VLAN27 (priority 1) on the other HP switch. One of the HP's is also the CIST root (spanning-tree priority 1). When I look at the spanning-tree output on the 3550 I can see that it sees the HP as the root for VLAN1, but it sees itself as the root for VLAN24 and VLAN27. The HPs also see themselves as root for their respective MSTIs so I've got loops in both VLAN24 and VLAN27. I've searched high and low for some solid evidence as to why this is and I am back to square one. According to the Cisco documentation "As the MST region now replicates the IST BPDUs on every VLAN at the boundary, each PVST+ instance hears a BPDU from the IST root (this implies the root is located inside the MST region). It is recommended that the IST root have a higher priority than any other bridge in the network so that the IST root becomes the root for all of the different PVST+ instances" (http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfc.shtml#recommended_configuration). In reading this it should seem that proper blocking is happening in the correct spot, but it's not. I've looked at pretty much all of HPs documentation on this as well as Cisco's but I'm not finding a definitive answer. Any help in understanding would be great.
2 REPLIES
gesadmin
Advisor

Re: ProCurve 2810 and Cisco switches

I should clarify what I mean here:
"One MSTI has VLAN24 (priority 1) and VLAN27 (priority 2) on one HP switch and VLAN24 (priority 2) and VLAN27 (priority 1) on the other HP sw". What I mean is on HP switch 1 MSTI1 is primary (priority 1 or 4096) and secondary on HP switch 2 (priority 2 or 8192). MSTI2 is primary on HP switch 2 and secondary on HP swtich 1
gesadmin
Advisor

Re: ProCurve 2810 and Cisco switches

So it looks like that document I referenced earlier only references Cisco's ability to interact with Cisco gear and not other gear that runs the IEEE MST. Why?? I don't know. If Cisco is truly compliant with the IEEE version why would it have issues?? Only Cisco knows. I love 'em, but I hate 'em too. Anyway, a bridging loop will form for any VLAN other than 1 if you've got multiple instances configured since Cisco will treat it not as MST but as traditional STP (CST). Hopefully this helps someone else.