Cell Relay Archive

[George Matey <gmatey@equipecom.com>]

Paul Koning wrote:
> 
> Kaushik Kuila wrote:
> >
> > Hello World!
> >   I know about LLCSNAP and NULL ENCAPSULATIONS for transmission of IP datagrams
> > over AAL5. Are there any other common encapsulations for transmitting IP over
> > ATM ?
> 
> It's really only the LLC/SNAP one.  Null doesn't work for IP because
> you can't send InARP packets over the same VC then...  don't know why
> it even appears as an option.

Null certainly does work for IP; for PVCs, all you need is either a
static adjacency (user configured) or a forwarding implementation
which can correlate an IP subnet with a PVC and forward on that (both
cisco and Juniper support this).

Why use Null?  For those ISPs that used ATM as transport, some used
Null to get better throughput from their ATM links.

--
George


> 
> Another possibility would be to send IP packets in ethernet format
> over an Ethernet bridged encapsulation.  That will show up if
> you're doing bridging.  Apart from that, I wouldn't expect it; the
> LLC format is the main one.
> 
>         paul