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From: ddp+@ANDREW.CMU.EDU (Drew Daniel Perkins)
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: Re: SLIP for IBM-PC
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Date: Tue, 1-Dec-87 04:49:35 EST
Article-I.D.: andrew.AVgYaUy00UoJyPo2N2
Posted: Tue Dec  1 04:49:35 1987
Date-Received: Fri, 4-Dec-87 06:34:53 EST
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I've been thinking about this for quite a while now and I have a few ideas.  
I've been planning on putting together a proposal but haven't gotten the 
time...  There are three options that I see:

1.  Use the MIT SLIP.  It provides IP address assignment in the link layer 
protocol.  Gross, but it works.  The problem with this option is that it 
requires a modified driver at the server end.  I.e. it doesn't work with the 
UNIX SLIP driver.

2.  Use BOOTP more or less unmodified.  You quickly run into the issue Bill 
Westfield pointed out, lack of a unique serial number (ethernet address).  
However, assuming that the IP address is associated with the incoming port and 
NOT the PC, this is not a problem since the BOOTP server would always answer 
the same IP address to queries received on that port.  It wouldn't be too hard 
to modify the boot server to do this.

3.  Invent a new BOOTP-like protocol more appropriate for serial line use.  I 
think this protocol should be more capable than bootp/rarp type protocols and 
should allow you to configure a SLIP line in a number of different ways.  It 
should allow either end to request an address from the remote end OR allow 
either end to tell the remote end who it wants to be.  The remote end should 
have the capability of rejecting the desired address if that address would not 
allow packets to be routed correctly.  Both ends of the connection would be 
configured to operate in either mode, either through some kind of 
configuration info or maybe hardcoded into the particular implementation.  
I.e. maybe a UNIX SLIP implementation wouldn't allow the remote end to specify 
it's own address.

Drew