Slow STP convergence between Cisco IE5000 and 3rd party switch

[Ronit Bhattacharjee]

Team,

We have a setup in the lab where we connected an IE5000 stack with a 3rd party switch as shown below

The 3rd party switch is running RSTP IEEE 802.1w. The Cisco switch is running MST instance 0 and acting as a root.

spanning-tree mode mst
spanning-tree mst configuration
instance 0 vlan 1-999
name DL7
revision 1
!

1. The 3rd party switch is successfully detecting the Cisco IE5000 as root bridge

2. The 3rd party switch is successfully transitioning one of the links to discarding mode to avoid loops

However, when the forwarding link is disconnected, it takes ~34 seconds for the discarding link to transition to forwarding. 

Is this normal? The 3rd party switch doesn't have an option to change the spanning tree mode.

[balaji.bandi]

High level switch side timers are good (until you like to decrease them look below  fine tune guide)

https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/19120-122.html

what is the timers on 3rd party switch (refer their document and make sure you setup as Cisco side to get optimal results.)

[Ronit Bhattacharjee]

Timers are default on both sides. 

hello 2, max age 20, forward delay 15

Looks like the problem is Cisco side is using MST0 and other side is using RSTP 802.1w

[balaji.bandi]

we understand the cisco side - how about another side?

The question is do you need MSTP in your environment, if not i will move to RSTP and test it.

[Ronit Bhattacharjee]

The other side is 802.1w RSTP. There's really no need for MST for us. How do we get the Cisco side to run 802.1w RSTP? What are the commands?

[MHM Cisco World]

can you see
show spanning tree 
if it (p2p) stp then both SW use legacy STP to connect and it take around 30 sec. 

[Ronit Bhattacharjee]

The output of "show spanning-tree" is in the diagram in the original post

[MHM Cisco World]

this cut there is no info about port run STP

[Ronit Bhattacharjee]

Apologies, full output attached. Yes, it looks like P2P. Why is it P2P and what can I do to prevent this from happening?