From: Dillon Yang (gzdillon@hotmail.com)
Date: Sat Mar 26 2005 - 04:56:36 GMT-3
Hi, Balaji:
It sounds right. But if I am asked for a task that a port need to go to forwarding fastly and should change its state to block when it receive bpdu packets, what can I do?
bpduguard is not the answer for the port goes to err-disable, bpdufilter is not too, for the port lose its portfast attribute to normal STP process.
TIA
dillon
----- Original Message -----
From: "Balaji Siva" <bsivasub@gmail.com>
To: "Dillon Yang" <gzdillon@hotmail.com>
Cc: "Group Study" <ccielab@groupstudy.com>
Sent: Saturday, March 26, 2005 2:34 PM
Subject: Re: bpdufilter vs bpduguard
> BPDU filter = stops "sending" bpdu on the port-fast enabled port
> BPDU guard = err-disable if the switch "receives" a bpdu on a
> port-fast enabled port
>
> BPDU filter enabled port does not send BPDU.. STP disabled port does
> not send BPDU. Since Portfast is also enabled, the port goes directly
> to forwarding so basically the port acts as if STP is disabled on the
> port (but in fact it is running and it would save you from shooting
> yourself in the foot if you had actually disabled STP completedly on
> that port)
>
> HTH
> Balaji
>
>
> On Sat, 26 Mar 2005 09:54:01 +0800, Dillon Yang <gzdillon@hotmail.com> wrote:
> > Hi, group:
> >
> > I'm confused by the two command "spanning-tree bpdufilter " and "spanning-tree bpduguard enable ".
> > <quote> If a BPDU is received on a PortFast-enabled port, the port loses its PortFast-operational status, and BPDU filtering is disabled. </quote>
> >
> > So I think the former do nothing with filtering and the latter truly filter the BPDU by making the port "error-disable".
> >
> > <quote> Caution Enabling BPDU filtering on an interface is the same as disabling spanning tree on it and can result in spanning-tree loops. </quote>
> >
> > I can not understand how "BPDU filtering " is the same as "disabling spanning tree "?
> >
> > TIA
> > dillon
> >
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