Path: utzoo!utgpu!water!watmath!clyde!rutgers!ames!ucbcad!ucbvax!VENERA.ISI.EDU!braden
From: braden@VENERA.ISI.EDU
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Routers vs. Bridges
Message-ID: <8712101742.AA23362@braden.isi.edu>
Date: 10 Dec 87 17:42:18 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 13

Here is one way you might decide if a given box is a bridge or an IP gateway
(aka router): see if it forwards a local network broadcast packet. A
bridge "must" forward broadcasts, while a gateway "must never" forward one.

Another test: see if the IP network number changes when the packet is
forwarded.  A bridge must not change anything in the IP header, while a
gateway "must" change the IP destination address.

These two tests give some clues about the advantages of gateways over
bridges.

   Bob Braden