[Rstplib-users] RE: operEdge: per Port or per MSTi in 802.1s ?

[<al...@nb...>]

But all decision about Port Roles & Port states and
optimizations with Designated Port agreement handshake
we make "per MSTi", don't we ?

Another words: if in all VLANs, mapped to the MSTi,
there is no STP bridges,
connected to the Port, may we think, that operEdge
of this Port is TRUE *in this MSTi* ?

The similar considerations about portEnabled: may the port be
enabled in some MSTi (i.e. for all VLANs from this MSTi) and
disabled in another one ?

Best regards, Alex
---------------------
Open Source RSTP  https://sourceforge.net/projects/rstplib/
Optical Access Ltd. http://www.opticalaccess.com

> -----Original Message-----
> From: Tony Jeffree [mailto:to...@je...]
> Sent: Thursday, December 13, 2001 1:37 PM
> To: Ar...@op...
> Cc: std...@ie...; rst...@li...
> Subject: Re: operEdge: per Port or per MSTi in 802.1s ?
> 
> 
> The use of operEdge to signal an edge port allows the 
> Spanning Tree state 
> machines to make optimizations in transitions to Forwarding 
> on such ports, 
> based on the assumption that because the port is an edge port, there 
> is   no bridge attached to the port (which, by definition, 
> would mean that 
> the port is not an edge port).
> 
> Seeing *any* BPDU on a port that had been flagged as an edge 
> port means 
> that there is a bridge out there - and therefore, that the 
> port is not at 
> the edge of the bridged LAN, and therefore, any spanning tree 
> optimizations 
> that were based on the assumption that the port was an edge 
> port are no 
> longer valid.  Continuing to behave as an edge port in these 
> circumstances 
> would carry the risk of creating loops in one or more of the 
> MSTIs and/or 
> CIST. Hence, it is only necessary to have a single instance 
> of the variable 
> per port for it to do its job.
> 
> Regards,
> Tony
> 
> At 12:10 13/12/2001 +0200, Alex Ruzin wrote:
> 
> >Hi,
> >
> >In 13.25 of 802.1s it is pointed, that the variable operEdge 
> is  "single
> >per-Port instance
> >applies to the CIST and to all MSTIs."
> >
> >Why ?
> >If a Port had received BPDU with tag of some MSTi and had
> >not received any BPDU from another,
> >why we have to consider it as operEdge port in this second MSTi ?
> >
> >Best regards, Alex
> >---------------------
> >Open Source RSTP  https://sourceforge.net/projects/rstplib/
> >Optical Access Ltd. http://www.opticalaccess.com
> 
>