[comp.sys.mac.programmer] BroadCasting over Appletalk

mikeoro@hubcap.clemson.edu (Michael K O'Rourke) (07/04/89)

I've got 2 appletalk programming questions.

First, I know that with a DDPWrite, if i set the nodeid to 255, it will 
broadcast the message of the net.  Will ATP do likewise if i set the nodeid
to 255?

Second, does anyone have sample code to determine a network/zone id number
if i know its name?  I know how to get the names from the sample code on
AppleLink.  I looked in inside appletalk, but their example of the packet
structure to do this didn't make sense to me.

Thanks,
Michael O'Rourke 

amanda@intercon.uu.net (Amanda Walker) (07/06/89)

In article <5911@hubcap.clemson.edu>, mikeoro@hubcap.clemson.edu (Michael K
O'Rourke) writes:
> First, I know that with a DDPWrite, if i set the nodeid to 255, it will 
> broadcast the message of the net.  Will ATP do likewise if i set the nodeid
> to 255?

Wince.  ATP is strictly a transaction protocol (hence the "T"), and only
works between two nodes.  If you think about it, the reasons are pretty
simple: you'd have to maintain retry timers and so on for each node, and
thus you'd need to know what nodes are out there in advance...

--
Amanda Walker  <amanda@intercon.uu.net>
InterCon Systems Corporation

paul@taniwha.UUCP (Paul Campbell) (07/06/89)

In article <1152@intercon.UUCP> amanda@intercon.uu.net (Amanda Walker) writes:
>In article <5911@hubcap.clemson.edu>, mikeoro@hubcap.clemson.edu (Michael K
>O'Rourke) writes:
>> First, I know that with a DDPWrite, if i set the nodeid to 255, it will 
>> broadcast the message of the net.  Will ATP do likewise if i set the nodeid
>> to 255?
>
>Wince.  ATP is strictly a transaction protocol (hence the "T"), and only
>works between two nodes.  If you think about it, the reasons are pretty
>...

Actually you can use the non-exactly-once form of ATP to talk to a known
socket in a sort of broadcast to all the servers on a net using this socket
number, you simply get back the first one that replies (you probably have
to ask for just one packet in response).

This is of course not recommended due to the havock lots of this sort of
thing plays with a net of any size [do not try this stunt at home ....].
Also DDP's lack of an internet broadcast (hooray!) makes this inconvenient
to do on any other than the local wire.

	Paul


-- 
Paul Campbell    UUCP: ..!mtxinu!taniwha!paul     AppleLink: D3213
"Free Market": n. (colloq.) a primitive fertility goddess worshipped by an
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