Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uunet!ubvax!csr
From: csr@ubvax.UB.Com (Chris Ranch)
Newsgroups: comp.protocols.appletalk
Subject: Re: tcp/ip
Message-ID: <33804@ubvax.UB.Com>
Date: 5 Oct 90 23:43:21 GMT
References: <5A0A0406200600BE-MTABOGECNVE*MUCM000@BOGECNVE>
Reply-To: csr@ubvax.ub.com.UUCP (Chris Ranch)
Organization: Ungermann-Bass, Inc.
Lines: 45

Fred, You wrote:
>  a)  A router that will take IP packerts from another network
>  (like an ethernet) and ship them over to the localtalk in IP
>  format.  Does this include the fastpath?  Ethergate?  GatorBox?
>  MultiGate?  Ungermann-Bass?  Anyone else?
>  b) A bridge that will encapsulate IP packets into AppleTalk packets
>  and ship them over to the Localtalk network.
>Is this right?  

	Basically.  Any IP packets that are on LocalTalk are in reality
	encapsulated in DDP (AppleTalk Network Layer).  The terms used
	to describe this encapsulation process as IP in Appletalk forwarding
	agents.  Thus, a) and b) are really the same, however b) stating
	the use of bridges (ddp net# is the same on both sides) is a misnomer.
	
>What are the advantages/disadvantages of each
>of these methods?  

	AppleTalk encapsulation of IP is the only known way to ship IP
	packets over LocalTalk.  IP packets will not traverse AT routers
	unless they are encapsulated in AT.
	
>Also,
>Encapsulated IP packets, though they would solve the appletalk
>router problem, would need to be treated differently at the Macs
>since telnet software is looking for IP packets, not
>encapsulated packets.  is this right?  Does anyone know what
>software will do this?

	You are right.  NCSA Telnet and MacTCP applications do precisely this.
	Ungermann-Bass MaxTalk performs the IP forwarding agent process.

>2)  A completly unreleated question to the above:  Can AUX broadcast...

	I don't know the answer to this one.

>Thanks,
>Fred Seaton
>Western Illinois University

Regards, and call if you have more questions.
-- 
Chris Ranch
Ungermann-Bass, Inc.
(408)562-7957      csr@ubvax.ub.com