Cell Relay Archive

[albert.e.manfredi@boeing.com]

To see how IP over ATM UNI 3.1 supports IP multicast, see RFC 2022. It
does so by means of a MARS (Multicast Address Resolution Server). The
MARS holds a table of ATM addresses that correspond to each multicast
group identified by an IP Class D address (i.e. a mapping of IP Class D
address to a list of AESAs).

Either the source of the multicast, or a dedicated server called
Multicast Server (MCS), is assigned the task of setting up the pt-mpt
SVC (using the "add party" ritual of UNI 3.1 or 4.0). Hosts wanting to
join or leave a group do so by contacting the MARS. The MARS then
informs the multicast source (or the MCS) of the group membership.

Alternatively, LANE can be used. LANE's Broadcast and Unknown Server
(BUS) would either flood multicasts to all its SVCs, to emulate the way
a shared Ethernet would forward IP multicasts, or LANE v2.0 can also
set up SVCs for smaller subsets of users in the emulated LAN. But it
has to be told what the group membership is.

In all cases, whether RFC 2022 or LANE, the multicasts are one to many.
If a return path is required, a multicast pt-mpt VC must be set up for
each other source. Which is really the way IP multicast works anyway.

Bert
manfredi@arl.bna.boeing.com


In article <3842D3D5.287265CF@aur.alcatel.com>,
  "Michael D. Todd" <toddmd@aur.alcatel.com> wrote:
>
> I assume you are talking about point-to-multipoint which
> is supported in Uni 3.1 & Uni 4.0. Pt2multipt is unidirectional
> (root UNI multicasts cells to leaf members.) I can't see how
> pt2mpt would work in a IP/ATM env. First, an IP/ATM (RFC1577)
> endpoint has a VC to each endpoint/IP address it talks to and
> needs bidirectional VCs (ping expects a reply, TCP has end2end flow
> control.)
> Second, IP/ATM encodes the VP/VC as a MAC address & puts it
> in the ARP table. If you have a VP/VC that corresponds to
> several endpoints & therefore IP addresses, I'm not sure how
> ARP would work. Maybe theres some way to couple multicast IP
> addresses to multicast VCs, but I don't know of an RFC which
> extends 1577 (maybe something like 2225 now.)
>
> mredondo@my-deja.com wrote:
> >
> > Hi, all
> > I´m looking for information about setting multicast groups
dynamically
> > in a IP-over-ATM enviroment. I think UNI 4.0 supports native
multicast,
> > but I´m not sure if there are any ATM switches that suport this
feature.
> > Is it possible to create a IP-over-ATM multicast network for audio
> > conferencing?
> > Is there anything already developed?
> > Thanks in advance
> >
> > Miguel Redondo
> > mredondo@idecnet.com
> >
> > Sent via Deja.com http://www.deja.com/
> > Before you buy.
>
> --
> Mike
>
> Michael Todd; Alcatel USA; Raleigh, NC USA


Sent via Deja.com http://www.deja.com/
Before you buy.