From: Michael Popovich (m.popovich@xxxxxxxx)
Date: Sat Dec 08 2001 - 11:47:44 GMT-3
It is my understanding of the portfast command that if both ports on
both sides are configured for portfast it will indeed immediately start
passing packets even if there is a loop in the network. However, that is
only temporary. I understand that the spanning tree algorithm is still
running and after the 50 seconds it takes to run that loops will be
detected and spanning tree will run as normal. Portfast doesn't disable
spanning tree.
MP
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Phil
Sent: Saturday, December 08, 2001 8:16 AM
To: Taz Kazam; Rivron Francois; thegroup
Subject: RE: Spantree Timer
If you have a port with portfast enabled when you connect it to another
switch port it will be automatically placed in disable, unless that
other port os also configured with portfast enabled (and in this case
they will not block and a loop will occur). Phil.
Taz Kazam <taz_kazam@yahoo.co.uk> escreveu: Thanks Francois
I managed to find out. I think that the Cat1900 has
the ports status set to PORTFAST by default (command: start-forwarding),
hence, it removes the foward delay time (15+15) = 30 sec, only using
MaxAge = 20 sec.
If you configure the port with no start-forwarding
i.e. disable the PORTFAST, it then takes the 50
seconds to change over.
Thanks you you reply.
Taz.
--- Rivron Francois
wrote: > Hello,
> my think is as the switch is able to detect a fault
> at a physical level, the
> port state of the redondant link is move directly to listening state.
> So the redondant path should be on in 30s.
>
> Francois
>
> > -----Message d'origine-----
> > De: Taz Kazam [SMTP:taz_kazam@yahoo.co.uk]
> > Date: vendredi 7 dicembre 2001 10:38
> > @: thegroup
> > Objet: Spantree Timer
> >
> > Can anyone help.
> >
> > I've step up four 1900 Catalyst switch in a loop,
> to
> > test spanning tree. One port changes its state to
> > blocking, as I expected, however, when I take the
> > cable out of the non-redundant path, which cause
> the
> > redundant path to change from blocking to
> fowarding -
> > it does, but it only take 20 seconds. From my
> reading
> > this should take 50 seconds (15sec fwd delay -
> 20sec
> > MaxAge) Blocking -----15-----Listen---
> > 15-----Learning----20------Fowarding. Im using the default factory
> > settings!
> >
> > Anyone can help?
> >
> > Taz.
> >
> >
>
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