[c-nsp] spanning-tree for local switching on ASR920

James Bensley jwbensley at gmail.com
Thu Oct 19 04:08:31 EDT 2017

On 19 October 2017 at 08:46, Gert Doering <gert at greenie.muc.de> wrote:
> Hi,
> On Thu, Oct 19, 2017 at 08:21:27AM +0100, James Bensley wrote:
>> >> Then configure STP for VLAN "10". It doesn't seem like there is any way
>> >> to map to an arbitrary PVST instance, VLAN ID and bridge domain ID has
>> >> to match.
>> I don't know the answer to you question but Peter's suggestion sounds
>> like a probably answer to me.
> I wasn't particularily asking for suggestions, but for "I have this
> working, and this is how it looks like".
> This box is unlike any other Cisco "switch-like thing" I've had in my
> hands before, so it might very well be just not supported at all.
>> However, you didn't share you STP
>> config, or was "l2protocol peer stp" all of it? :)
> There isn't anything else you *can* configure (except changing the
> global STP mode from pvstp to mst and back, and setup mst instances,
> which does not have an effecit either).
> So indeed, that's all there is, and the ASR920 MST/PVST+ documentation
> claims "there is nothing else you can do".
> *If* you have a vlan, you can do "spanning-tree vlan 10", but that is
> default anyway (= not showing up in the config), but since there is no
> "vlan 10" in the system, there's no spanning-tree instance for it either
> ("show vlans" comes up empty).

Open a TAC case, they'll probably tell you STP isn't supported and the
documentation is infact wrong, that is what has happened for me
recently with some ASR920s and ME3600s with a different feature than


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