[j-nsp] loop detection on EX4200

[Victor Sudakov]

Ben Dale wrote:
> 
> >> Could you not use MSTP or VSTP instead of RSTP?
> > 
> > Perhaps I'll have to unless I can make the multiplexer forward
> > untagged frames.
> 
> If the issue is that the multiplexer is not forwarding untagged
> frames, you'll need to use VSTP (aka PVST+).  MSTP will still send
> PDUs untagged.
> 
> If the issue is that the multiplexer is absorbing link-local traffic
> such as STP, then this is a difficult problem to solve.  I would
> normally suggest using something like storm-control with port
> shutdown, but being that this multiplexer will be max 2M of ethernet
> for the entire interface, tuning storm control will be quite
> difficult (since it is a global setting on EX42).

Not exactly 2M, it can utilize up to 4xE1 for ethernet traffic, but
still, you are right.

> 
> See if you can get something like LLDP across your multiplexer to a
> switch on the far side - that might point you in the direction of
> the issue.

No, LLDP does not work either across the multiplexer. If I configure a
vlan tag on the "default" vlan on the EX42, LLDP starts seeing the
EX42 on the other side.

That was the reason I had suggested that the multiplexer did not
forward untagged frames.

-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
sip:sudakov at sibptus.tomsk.ru