Date: Sat, 2 May 1998 17:22:50 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: itojun@itojun.org (Jun-ichiro itojun Itoh) Cc: current@FreeBSD.ORG Subject: Re: Infrared ? (a simple experiment for laptop owners...) Message-ID: <199805021522.RAA03142@labinfo.iet.unipi.it> In-Reply-To: <5313.894127506@coconut.itojun.org> from "Jun-ichiro itojun Itoh" at May 3, 98 01:44:47 am
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[forwarded to -mobile since it is probably relevant there --- i was wondering how hard would it be to implement a 'lightweight' IrDA to enable PPP between two FreeBSD laptops] > I've tried that several years before. > > If you open IR port as RS232C serial port (/dev/ttyd1), it will > behave as half-duplex serial port. The port is strictly half-duplex, > that is, if machine A and B send some bytes at the same time > they will collide and junk byte will be received. actually it seems that receive is disabled while transmitting, but the situation is no different from what you say. What i was wondering, though, is if we could implement some quick and dirty hack in iijppp to make it work. Example: one side (the 'client' ppp) acts as a master, the other one as a slave. The protocol is governed by the master, and the slave can only send a packet right after a pkt coming from the master. The master sends empty pkts if it has nothing to send, just to trigger responses from the slave. The slave sends empty pkts if it has nothing to send, just to keep the protocol up. The master will assume a failure in the slave if a pkt is not received after a timeout (conveniently larger than 1MSS at the link speed), and will transmit after a timeout even if no reply is received. The slave WILL NOT send after a timeout. This should be relatively easy to implement. Opinions ? cheers luigi -----------------------------+-------------------------------------- Luigi Rizzo | Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it | Universita' di Pisa tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ _____________________________|______________________________________ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-mobile" in the body of the message
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