RSTP and RPVST+ Integration

[dm2020]

Hi All,

I need some design advise with integrating a pair of Cisco 3750G switches operating RPVST+ and a HP Procurve switch running RSTP. See attached diagram

The HP Procurve switch has been set with an STP priority of 0, Cisco 3750G switch 1 has been set with an STP priority of 4096 for all VLANs and Cisco 3750G switch 2 has been set with an STP priority of 8192 for all VLANs. VLAN1 is not permitted on any of the inter-switch links.

From my understanding, as VLAN 1 is not permitted between the switches, the RSTP and RPVST+ domains do not interoprerate, however, as the RPVST+ BDPUs are simply tunneled over the RSTP domain, VLANs 10 and 20 are blocked Cisco 3750G switch 2 on the interface connecting to the HP Procurve switch thus preventing any loops.

Now I have tested this without any issues, however, I have been told that we must permit VLAN 1 on the interswitch links to allow the STP domains to interoperate correctly. Is that correct as there are no issues with the current configuration? What issues will I have if I dont allow VLAN 1 between the networks?

Thanks

[dm2020]

Hi All,

Any thoughts?

[paul driver]

Hello
You can implement MSTP on the Cisco which will allow the HP stp vlans be able connect to the mst region of the Cisco.
Even though you only show one HP switch here you could have an entire HP stp region running behind it and the Cisco will see this HP domain as a single internal STP instance (IST) connecting towards single common stp region meaning one stp instance (vlan 1) for all vlans as such it will allow the HP and cisco stp domains  to successfully work together

Please this this excellent blog about  MSTP

[CaiioJaks]

Thanks for the information, I will check-out the article.
In the MST implementation that you are suggesting, the MSTP on the Cisco devices, would be implemented on a per-interface basis?

[CaiioJaks]

Were you able to implement MST to integrate both regions (rpvstp and rstp)?