IE-3000 no spanning-tree mode pvst

[Mark Wardle]

spanning-tree mode pvst
spanning-tree extend system-id

The above lines of configuration appear seemingly by default in my IE-3000 switch configurations.  I have ran the no command on both lines but cannot seem to remove them.  Can anyone offer any advice on why? Are those spanning-tree configurations dependencies of another protocol or configuration (VTP perhaps)?

I have configured a REP ring with a number of these switches, which doesn't use STP as I understand it, so I am at a loss as to why these 2 lines of configuration are there.

Could this unwanted STP configuration do any harm to my network if left in place?

Any advice or an explanation is much appreciated.

[Mark Malone · Accepted solution]

Hi

if a port is part of REP it cant be part of STP so you should be good to leave that there , they can work in conjunction together and you cant remove the STP default from switch just change it or disable it per vlan /port but not required as REP will do that anyway once its set for REP

Spanning Tree Protocol Interaction

REP does not interact with STP or with Flex Links but can coexist with both of them. A port that belongs to a segment is removed from spanning tree control, and STP BPDUs are not accepted or sent from segment ports. Therefore, STP cannot run on a segment.

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/lanswitch/configuration/xe-3s/lsw-cfg-rep.html#GUID-28CDAB0B-991E-4FC9-A451-EFFDE6DCFFE8

[Mark Wardle]

Thank you for the reply.

So I just need to ensure I disable STP on each interface?

If I do so, will I still see STP packets if I put a sniffer on the network?

[Mark Malone]

Hi

no you don't need to do anything with STP if REP is configured it will automatically overrule STP process , you shouldn't see any BPDU packets for the interface if REP is enabled correctly if you span the port  

[Mark Wardle]

Forgetting the REP segment interfaces for a minute, what about the access ports on the switch?  Do I need to disable STP on those ports?

[Mark Malone]

You should never disable STP in any circumstance really as its your layer 2 loop prevention technology (sometimes 3rd party connected devices may not understand it that can be a case where you would disable the port not to participate in stp as it will cause network outage) , if you disable that and say you were not using REP your going to cause issues , STP should be left on and you should build a good topology of your layer 2 design with STP and have full control over it so if something happens you can nearly determine even though its automatic what will happen and what will take over when something fails

so no I would not disable STP

[Mark Wardle]

You've been very helpful.  It is much appreciated, thank you.