Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!apple!apple.com!rmh
From: rmh@apple.com (Rick Holzgrafe)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Appletalk Confirm
Message-ID: <4673@internal.Apple.COM>
Date: 11 Oct 89 18:36:14 GMT
References: <6724@hubcap.clemson.edu>
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 37

In article <6724@hubcap.clemson.edu> mikeoro@hubcap.clemson.edu (Michael K 
O'Rourke) writes:
> Does anyone know if a NBPConfirm in Appletalk generates network
> traffic and in which cases?  For instance, i assume it would have to
> talk to a bridge to get to another zone, but what about confirming 
someone
> on my own zone?  If they are on my zone will the names table in my 
machine
> be able to confirm them without causing network traffic?

NBPConfirm sends a directed message (not a broadcast) to the address 
you're trying to confirm. That machine returns a message confirming, 
correcting (if the node is correct but the socket wrong), or denying the 
match. Unless the address you're confirming is in your own machine 
(unlikely but not impossible), there will be network traffic: the names 
table in your machine lists only the entities in your machine.

NBP uses DDP to send its messages. DDP is "best effort", meaning that 
delivery is not guaranteed. If no response is received in time, NBP will 
re-send the confirmation request, hoping to finally "get through". NBP's 
patience between sends and the number of retries before giving up are 
specified by the caller. Note that in most cases, the match will be 
correct and the request will be quickly answered, so the network traffic 
will be minimal: one message, one response. But if the address is 
thoroughly bad (say, the target machine is turned off or disconnected) or 
if there's a lot of traffic or noise delaying or garbling transmission, 
then there'll be repeated attempts.

See "Inside AppleTalk", Chapter 7, "Name Binding Protocol", for a full 
discussion.

==========================================================================
Rick Holzgrafe              |    {sun,voder,nsc,mtxinu,dual}!apple!rmh
Software Engineer           | AppleLink HOLZGRAFE1          rmh@apple.com
Apple Computer, Inc.        |  "All opinions expressed are mine, and do
20525 Mariani Ave. MS: 27-O |    not necessarily represent those of my
Cupertino, CA 95014         |        employer, Apple Computer Inc."