On Tue, 2005-03-01 at 07:38, Mark Smith wrote:
> Are you able to put a rough date of manufacture on those cards/chipsets
> ? I've recently done a bit of looking into the chips on the old NE2K
> style cards (the NatSemi NS8390D chipset), and even they have a
> multicast filtering capability. I first encountered them on NICs in 1992
> (if not earlier, maybe 1990 or so), so I'm curious how much earlier
> before that multicast was implemented the way you have stated.
I think it's far more likely that Alexandru is running into broken
drivers and/or bridges.
I've seen:
1) device driver bugs. either they fail to program the multicast filter
or they try and get it wrong. A common multicast filter is a bit vector with
associated hash function. (if filter[hash(dst)] is set, receive packet). If
the driver miscomputes the hash function, bits don't move.
Many ethernet chipsets have a "receive all multicasts" bit, which at least
saves you from the full pain of promiscuous mode.
2) firmware bugs in 802.11 access points. (the vendor had a firmware
upgrade available fixing it by the time I noticed the problem).
- Bill
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