Default STP out of the box

[Pepe_Lepew]

If i have a 3800 switch for example.

By default spanning tree is disabled.

If i enable it by just entering "spanning-tree", what version of STP is enabled?

Is it always MSTP with only instance 0 preconfigured to handle all VLANs, waiting for me to create new instances?

Or is it RSTP or even CSTP?

[fjulianom@hotmail.com]

Hi Pepe,

The ACMA Official Certification Guide says that running that command you woud enable RSTP, but the HPE ArubaOS-Switch Advanced Traffic Management Guide K/KA/KB.16.01 is not clear about this. I would like someone with experience on this clears this doubt.

Regards,

Julián

[johnk3r]

Hello!

By default the switch does not have STP enabled, and when enabled, it will current as MSTP but with RSTP behavior because it does not have a configured instance.

[fjulianom@hotmail.com]

Hi John,

Is there any command to just enable RSTP or the only way is enabling MSTP without configuring any instance as you say?

Regards,

Julián

[Pepe_Lepew]

Is there a document which states for which physical switch series this applies to in combination with which firmware?

So basically you could say it's RSTP out of the box, with the OPTION to configure multiple instances.

If the output shows this:

# sh span

 Multiple Spanning Tree (MST) Information

  STP Enabled   : Yes
  Force Version : MSTP-operation

I can assume my switch is running at least MSTPI0/RSTP (instead of CSTP)?

For instance 0 you can't/don't need to define a config revision/name etc?

[johnk3r]

If you want to do the Vlans balancing which is the main feature of MSTP, you need to create the instances (1..2..3) and associate Vlan. This process must be done on all switches. This becomes complex when you have a significant amount of switches.

With the current configuration, MSTP + INSTANCE 0, the switch will behave as RSTP and you will have a free network of L2 loops

[fjulianom@hotmail.com]

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@johnk3rwrote:

Hello!

By default the switch does not have STP enabled, and when enabled, it will current as MSTP but with RSTP behavior because it does not have a configured instance.

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Hi johnk3r,

According to the ACMA Official Certification Guide:

You do not need to configure the instance 0 mapping; by default, instance 0 includes all VLANs that have not been mapped to a different instance.

If this is the behaviour, when you enable spanning-tree out of the box, instance 0 exists and then all the VLANs are mapped to instance 0. If so, MSTP would operate as MSTP with all the VLANs in instance 0. Why MSTP with RSTP behaviour?

Regards,

Julián