Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!uw-beaver!fluke!jeff From: jeff@tc.fluke.COM (Jeff Stearns) Newsgroups: comp.protocols.appletalk Subject: Re: AppleTalk in large diverse networks Summary: Is AppleTalk simply a *bad idea* in large, diverse networks? Message-ID: <3758@fluke.COM> Date: 13 May 88 20:53:17 GMT References: Sender: news@tc.fluke.COM Lines: 53 In article , xxss520@CHPC.BRC.UTEXAS.EDU ("L. Stuart Vance") writes: > As many of you already are aware, the current boom in the EtherTalk product > market has brought to the forefront two significant shortcomings of AppleTalk: > the limited number of hosts on a network, and the lack of security across > network boundaries. ... It's commonly stated that there is a limit of 254 hosts on an AppleTalk network, but we should recall that the actual limit is generally worse: 127 user nodes 127 server nodes Now allow me to include a third drawback, and then pose the Big Question... AppleTalk protocols have another undesirable trait, probably also a result of their "small-network" heritage: They depend heavily upon broadcast packets when acquiring a nodeID and when locating other network entities via the Name Binding Protocol. This may be tolerable in the LocalTalk universe where small networks are the norm. But running the AppleTalk protocols on EtherTalk looks ominous. Consider: a MINIMUM of 20 broadcast packets when acquiring a nodeID at reboot time. (Reading of the AcquireAddress() alogrithm in Inside AppleTalk suggests that things may be much worse in practice; there is NO upper bound on the number of broadcast packets emitted when nearly 127 user nodes are already in use.) Now the Big Question: I have an extended Ethernet of moderate size: five bridged segments supporting about 100 computers running TCP/IP. In the wings, several hundred PC's and Macintoshes awaiting connection, eager to run TOPS or AppleShare. What's going to happen when I try to connect, say, two hundred micros speaking EtherTalk? For starters, do I have to create several separate AppleTalk networks, just to handle the puny 127-node limit? (How do I do this on one extended LAN?) My Ethernet is bridged with DEC LAN Bridges, so broadcasts sail right through to all segments. Am I going to regret this? Am I going to regret EtherTalk, period? I'd especially love to hear from those of you who have EtherTalk networks in place. Respond by mail or news, as you see fit. Thanks! -- Jeff Stearns Domain: jeff@tc.fluke.COM Voice: +1 206 356 5064 If you must: {uw-beaver,microsoft,sun}!fluke!jeff USPS: John Fluke Mfg. Co. / P.O. Box C9090 / Everett WA 98206