Re: stds-802-16-tg1: Question: Data broadcast in 802.16 MAC

[Walt Roehr <w.c.roehr@ieee.org>]

Vladimir,
Unless I misunderstand Ken, there is already a multicast (simultaneous
transmission to a designated subset of subscribers -- subset COULD be
everyone) capability.  In general, I would expect the multicast to be
more appropriate for the ISP situation:

a. it's likely that there is more than a single ISP using the system
(the will be some subscribers who are NOT the ISP's clients).  Accepting
the definition of "broadcast" as being EVERYONE receives it, broadcast
would NOT be appropriate -- the P2MP subscribers who are NOT ISP clients
would also be receiving the broadcast.

b. Even within the ISP's clients I would expect that there are some of
the clients that have no interest in a given transmission -- so even if
the ISP was the only one using the system BROADCAST would not be
appropriate.

Ken, do I have it straight about "broadcast" and "multicast"?

cheers,
Walt

Vladimir Yanover wrote:
> 
> Ken,
> 
> Thanks for your detailed answer.
> I believe that any P2MP system intended to connect subscriber sites
> to an ISP needs broadcast functionality, simply to transfer efficiently
> IP broadcasts that otherwise should be copied potentially to each
> connection.
> This is so general that worse to be serviced somehow in the standard.
> Your recommendation to define in the spec [of the standard - VY] a
> well-known
> broadcast data transport connection [different from the Management broadcast
> 
> connection - VY] seems to be the best solution.
> 
> Vladimir
> 
> > -----Original Message-----
> > From: Ken Stanwood [mailto:ken@ensemble.com]
> > Sent: Thursday, August 02, 2001 9:02 PM
> > To: Vladimir Yanover; Carl. Eklund (E-mail); 802.16 TG1 Reflector
> > (E-mail)
> > Subject: RE: stds-802-16-tg1: Question: Data broadcast in 802.16 MAC
> >
> >
> > Vladimir,
> >
> > The broadcast connection is not a data transport connection,
> > and user data
> > should not be sent on it.  There is the problem of connection
> > parameters,
> > which convergence sublayer to use, etc. that would make it
> > problematic, and
> > point out that it would actually be a layering violation.
> >
> > Instead, if you need broadcast data under the current spec,
> > you should set
> > up a multicast transport connection and have all SS belong to
> > that multicast
> > connection, making it effectively broadcast.
> >
> > Alternatively, if this broadcast data connection would always
> > be present in
> > certain types of systems, you could define in the spec a well-known
> > broadcast data transport connection with well known parameters and
> > convergence sublayer.  That would eliminate the need to join
> > every SS to the
> > multicast connection.
> >
> > Ken
> >
> > -----Original Message-----
> > From: Vladimir Yanover [mailto:vladimiry@breezecom.co.il]
> > Sent: Thursday, August 02, 2001 12:09 AM
> > To: Carl. Eklund (E-mail); 802.16 TG1 Reflector (E-mail)
> > Subject: stds-802-16-tg1: Question: Data broadcast in 802.16 MAC
> >
> >
> > Carl and All,
> >
> > Can you please clarify the issue of data broadcast in 802.16 MAC.
> > [Obviously, there may be a need for broadcasting data to all SSs]
> >
> > If it is allowed to send data traffic at broadcast CID, then
> > there may be a
> > problem with recognition
> > of Management messages sent at the same CID. Such a
> > recognition is needed to
> > decide whether we need
> > to pick up Management Message Type for further parsing
> >
> > Thanks
> >
> > Vladimir
> >