
The established standard for Amiga networking devices is SANA-II
Release 2 (S2R2) as specified by Commodore. Note that the "R2" is
fairly important these days. The standard is documented in the
"sana2_v2.lha" archive. We'd like to leave the contents of this
archive "as is" in the moment.

As there has been some confusion about the filtering and multiple
protocol stack support options, let us clarify this a little bit.


Packet filtering
----------------

What does packet filtering do? With the original SANA-II standard,
a protocol stack could open a device and ask for certain packet
types. It got all the packets that matched this type. As it turned
out, this could be mighty inefficient if there were packets that
the protocol stack did not use at all.  These would go into read
processing of the protocol stack and waste CPU time even though
they could have been easily identified on arrival.

So the filtering tag has been introduced into S2R2.

Multiple Protocol Stack Support
-------------------------------

Basically this means that each opener gets all the packets
necessary. If a packet comes in that fills a request for more than
one opener of the device, all of them will get a copy of the
packet.

Heinz Wrobel
<heinz@amiga.de>


