[j-nsp] Topology failure on EX4200

Victor Sudakov vas at mpeks.tomsk.su
Tue Jul 18 00:57:06 EDT 2017

Roger Wiklund wrote:
> I'm not sure what happens exactly without show output during the failure.

What show output would be useful do you think?

> I was just guessing that you need loop protection because you have a
> failure of an intermediate device, so interface is still up but you
> stop receiving BPDUs, 

That's a correct description of the situation.

> and thus transition from blocking to forwarding
> on your specific mgmt VLAN, 

I forget to mention that the devices are running MSTP, with a single 
MSTI, so there's essentially only one topology. 

> and creating a black hole. Again just a
> guess I might be wrong.

You are probably right, the question is why only the management
traffic (vlan3) is being blackholed, and not the customers' traffic.
If MSTP did create a blackhole, it would create it for the whole
traffic, right?

> EX4200 and EX4550 have dedicated high speed VC ports, but you can use
> your 10G optical interfaces instead.

Ah, sorry, I have none of those.

Victor Sudakov,  VAS4-RIPE, VAS47-RIPN

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