[ifi <ificidte@xxxxxxxxx>]

Some googling tells me that the 'Port Identifier' on a Cisco is in fact 
just the MAC address of the port you're connected to.

Another source suggests that the port identifier is an "Unsigned binary 
number used as port priority (lesser number denotes higher priority)."

Stef wrote:
> Thanks, but ... comments in line
>
> On Mon, 8 Nov 2004 03:00:59 +0100, Joerg Mayer <jmayer@xxxxxxxxx> wrote:
>
> > On Sun, Nov 07, 2004 at 12:10:21PM -0600, Stef wrote:
> >
> >
> >
> > > Replying to my own post: digging further, I have found the
> > > specification for STP calling for port ID in the format 0x80YY, where
> > > YY is the HEX number for the port ID on the switch (at least this is
> > > my understanding). So - in my case I should only look at the last two
> > > "digits" (actually hex numbers), directing to a port number like:
> > >
> > > "CD" in hex = 205 in dec. ==> port number being 205 (?!?).
> > >
> > > I have tried to make sense of the above, assuming that the numbers are
> > > counted from the beginning of a set of modules (e.g. for a chassis
> > > with multi-port multiple modules), but still cannot come up with the
> > > proper explanation. For example, in my case this traffic is caused by
> > > port 37 on module 4 (4/37), with 2 previous modules (first is the SUP,
> > > thus module 4 for the one I am investigating) with 48 ports each ==>
> > > 205 - (2 * 48) = 205 - 96 = port 109 (?!?)
> >
> > With STP, there are two ways to interpres the port identifier:
> > - 8 bit priority + 8 bit port number (the old way of doing this)
>
>
> This is what I assumed. No go, as you probably have already noticed
> (CD=205 - no such port pn a switch). Or perhaps the Cisco port
> numbering has nothing to do with the decimal equivalent of the last
> 8bit entry of the port ID?!?
>
>
> > - 4 bit priority + 12 bit port number (the 802.1t aka new way of doing it)
> >
> > Ciao
> >  Joerg
> >
> > --
> > Joerg Mayer                                           <jmayer@xxxxxxxxx>
> > We are stuck with technology when what we really want is just stuff that
> > works. Some say that should read Microsoft instead of technology.
>
>
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