Date: Sat, 08 Jul 1995 17:00:51 +0000 From: Matt Thomas <matt@lkg.dec.com> To: Julian Howard Stacey <jhs@vector.eikon.e-technik.tu-muenchen.de> Cc: hackers@freebsd.org, n1epo4tl@ibmmail.com Subject: Re: token ring anyone Message-ID: <199507081700.RAA06452@whydos.lkg.dec.com> In-Reply-To: Your message of "Thu, 06 Jul 1995 16:35:57 %2B0200." <199507061435.QAA03684@vector.eikon.e-technik.tu-muenchen.de>
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> a couple of weeks ago I asked (on behalf of n1epo4tl@ibmmail.com Stuart
> Arnold) if anyone knew of any support for token ring cards with FreeBSD,
> we heard nothing ... either there's no interest or maybe it was mail
> failure ?
Token Ring is a proverbial pain in the ass.
Unlike writing a new Ethernet driver, Token Ring also involves writing
the Token Ring support code, modifying IP Multicast to work over Token
Ring (ie. map to the right funtional address), and, worst of all,
modifying ARP so that it understand how to do source routing.
Of course this ignores the fact that you really want fairly generic source
routing so you could use it with IPX or OSI or whatever else is around.
The major Token Ring chipsets are fairly painful. It also means that
the driver writer have the infrastructure to test the driver (unlike
Ethernet where you can plug two systems back-to-back or use some ThinWire
Token Ring requires a MAU). If you don't need to test source routing,
thin a single ring will be fine otherwise you'll need a bridge. You also
need a router to make sure you are dealing with stupidity of bit-flipped
ARP address properly.
Instead of writing token ring drivers, I think it would be a far better
investment to write NDIS3 miniport wrapper code for FreeBSD but I digress.
So in essence, until the pain of not having Token Ring exceeds the pain
threshold of implementation it's unlikely to be done.
That's my take on it.
Matt Thomas Internet: matt@lkg.dec.com
3am Software Foundry WWW URL: <currently homeless>
Westford, MA Disclaimer: Digital disavows all knowledge
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