17 Aug
2014
17 Aug
'14
3:50 p.m.
On Aug 17, 2014, at 17:27, Charles Dickman <chd at chdickman.com> wrote:
Curious if anybody else has similar trouble when mixing old with new
and slow with fast.
Put shortly, yes. I believe (but have not confirmed) that it has to do with
autonegotiation from the faster switch not playing nicely with 10BaseT hardware not
designed for autonegotiation. The chief symptom I tend to see is about a ~1s vacillation
between link up and down on the switch.
A slower switch or hub in between seems to help, as you've noted. I've found the
problem with a lot of old Mac Ethernet cards, a lot of which we're based on National
Semiconductor silicon (SONIC, ST-NIC chips and variants), but I'm sure it's not
unique; it also seems to mostly be confined to crappier switches (my managed 24-port
gigabit switch had no problems with my DELQA).
- Dave