Re: Subject: I-D ACTION:draft-clausen-ipdvb-enc-00.txt

["Kearney" <clausen@cosy.sbg.ac.at>]

From: "Ghassane Aniba" <Ghassane.Aniba@sophia.inria.fr>
Sent: Wednesday, April 24, 2002 5:41 AM
Subject: Re: Subject: I-D ACTION:draft-clausen-ipdvb-enc-00.txt


...SNIP...

> > Without layer 2 source address, how do we recognize our own datagrams,
> > when we get them back on the link several ms after sending them.
> > ...
> >
> > If we are really convinced that in some cases either the destination
> > and/or source MAC address are uneeded, and if the goal is to save some
> > bits not having them, we could use 2 bits out of the length field
> > The length field would then be 14 bits ([0,16383])
> > MAC_FLAG
> >
> > 00 : no dst MAC, no src MAC
> > 01 : dst MAC, no src MAC
> > 10 : src MAC, no dst MAC
> > 11 : dst MAC, src MAC
> >
> > MAC is IEEE 48 bits
> > no dst MAC is equivalent to a broadcast: ff:ff:ff:ff:ff:ff
> >
> > +--+--------------+----------------+----------
> > |00|    length    |      type      |Payload
> > +--+--------------+----------------+----------
> >
> > +--+--------------+----------------+-----------  --+----------
> > |01|    length    |      type      |48 bits dst ~  | Paylaod
> > +--+--------------+----------------+-----------  --+----------
> >
> > +--+--------------+----------------+-----------  --+----------
> > |10|    length    |      type      |48 bits src  ~ | Paylaod
> > +--+--------------+----------------+-----------  --+----------
> >
> >
--+--------------+----------------+-----------  --+-----------  --+---------
> > |11|    length    |      type      |48 bits dst ~  |48 bits src ~
|Payload
> >
--+--------------+----------------+-----------  --+-----------  --+---------
> >
> > Patrick.
> But for the satellite network, how we can switch MPEG2-TS packet
> onboard?
>
Ghassane,
by including this (hopefully not 48 byte long) address or label in every TS
packet just as you proposed in your previous messages. In that case you do
not have to include it in the encapsulation and bind it directly to the
higher-layer address, e.g. IP multicast.
> --
> Ghassane ANIBA