Path: utzoo!utgpu!watmath!att!pacbell!ames!mailrus!tut.cis.ohio-state.edu!uc!nic.MR.NET!ns!jmh
From: jmh@ns.network.com (1606)
Newsgroups: comp.dcom.lans
Subject: Re: BRIDGE's (ROUTER's) (GATEWAY's)
Summary: The Difference
Keywords: Distinction
Message-ID: <1527@ns.network.com>
Date: 7 Aug 89 13:15:09 GMT
References: <11146@ibmpcug.UUCP>
Sender: jmh@ns.network.com (Joel Halpern 424-1606)
Reply-To: jmh@ns.UUCP (Joel M. Halpern 612-424-1606)
Organization: Network Systems Corporation
Lines: 16

My understanding of the Differences among the three terms (Bridge, router,
gateway) as the standards community is attempting to use them is:

	A Bridge is a layer 2 device,
	A Router is a layer 3 device (hence protocol dependent)
	A Gateway is a layer 7 device designed for one or more specific
		applications.

    There is some use of interconnection devices at layer 4.  These devices
    (aside from the irrelevant fact that the ISO environment tries to claim
    that there should be no such thing) do not yet have a clear name.  As they
    are usually intended to convert between two protocol families, I tend to
    refer to them as layer 4 routers, but even that is sloppy and misleading.

Joel M. Halpern				jmh@nsco.network.com
Network Systems Corporation