Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!sdd.hp.com!decwrl!ucbvax!MATHOM.CISCO.COM!BILLW
From: BILLW@MATHOM.CISCO.COM (William "Chops" Westfield)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Talking to cisco routers with Unix machines
Message-ID: <12614941747.9.BILLW@mathom.cisco.com>
Date: 19 Aug 90 04:24:39 GMT
References: <1990Aug18.225126.3678@santra.uucp>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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    >Has anyone had any experience using SLIP and/or PPP from a Sun
    >(a 3/50 or SPARCstation) at 56 or 64Kbits/sec?  I'm interested
    >in using one of the serial ports to do this.

You really do NOT want to do this.  The zippy CPU in a sparcstation
is much better off doing user stuff, rather than trying to service
13000 interupts/second.  Servicing interrupts is not something that
most risc processors are good at.  I've heard people complain about
the impact of much slower SLIP connections.

You would be better off getting a sync serial interface, which only
interrupts the CPU per frame, or a stand alone router box.


    To extend, has anyone written software to talk to Cisco routers at 64
    kbits/sec ?  I understand that Cisco's support SLIP, but can that be
    run at 64 kbit/s ?

The maximum speed of an async SLIP line on a cisco terminal server is
38400 bps.  Faster than that we like to do frame-at-a-time sync serial
too (and you use a router instead of a terminal server.)


    I suppose the protocol Cisco routers use to talk to each other is not
    any standard protocol but Cisco's own.  Are the protocol specs
    available ?  If not, would Cisco object to someone reverse-engineering
    the protocol ?

We have told people the spec.  I don't know whether anyone has
actually done anything with it.  The current software also supports
the IETF Point-to-Point protocol for IP on sync serial lines, which is
probably a better idea.

    A local PTT here offers a service to connect company LANs together
    with Cisco routers; if a general-purpose Unix machine could talk the
    Cisco protocol and route the traffic (perhaps also DECNET traffic) one
    could save the money needed to buy the Cisco router.  Well, perhaps I
    shouldn't have said that because I suppose it's not in the best
    interests of Cisco ;-)

This sort of thing is exactly what the PPP spec is supposed to solve.
This is tcp-ip, you don't have to be nice to cisco.  Actually, you
don't have to be nice to us on the cisco mailing list either  :-)

Bill Westfield
cisco Systems.
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