Cell Relay Archive

[Matt Clark <matthew.w.clark@bankerstrust.com>]

Vincent BERRUYER wrote:
> 
> Hi,
> 
> Can someone explain the way multicast are managed using LANE services ?
> I suppose they are sent to the BUS which will broadcast them to its LEC.
> Is there any use of the ATM point to multipoint capabilities for IP
> multicasting ?
--snip--
> If this is the way multicast are managed by LANE services, it seems strange
> than in an ATM network with point to multipoint capabilities, IP multicast
> are broadcasted !!

Hi Vincent,

In LANE version 1 multicasts are indeed broadcasted (remember that
broadcasts are really just a special (degenerate?) case of multicasts).

LANE version 2 introduces optional multicast services.  Multicast
support is optional at the LEC, support for *registering* multicast MAC
addresses is mandatory at the LES, but support for actual multicast
forwarding is optional, as the LES *may* revert to treating multicasts
as broadcasts.

See the LANE v2 spec at www.atmforum.com.

As for why it's not in LANEv1, IMHO it involves a fair bit more
intelligence in the LECs than was thought reasonable at the time.

Matt