: I have a general networking question.
: How the hell do dual-speed hubs work?
there are bridged segments and when a port is seen to be 10 or 100,
its placed on the appropriate 'bridge group' (the 10 group or the 100
group). then those two groups are grouped together. that's one way.
another way is that all ports of a speed/type are repeated and the
10's and 100's are bridged (buffered) together. I think that's the
way my mini bay net 10/100 hub works.
finally, on the high end, each port can be buffered separately (have
its own MAC) and the switching/routing/bridging logic passes datagrams
to/from ports when they're clear. queueing them when they're not
clear.
: I have a couple of new DS108 units from Netgear. These are dual-speed hubs
: (not switches) that auto-sense the speed of the connection.
: When 10 Mb are talking to 10 Mb, or 100 Mb are talking to 100 Mb, everthing
: is fine.
: When they try and talk with each other (10 to 100 or 100 to 10) the whole
: segment goes to hell. Packets are lost, the collision lights blink a nice
: steady pattern, and everything slows to a crawl.
maybe you have duplex mismatches? if you're 'hubbing' then its
probably best to set things to all the same duplex: full or half.
10meg is usually half and 100meg is usually full, but auto-negotiation
rarely works well, so it sometimes helps to force one end to a known
steady state and let the other negotiate. can you try setting your
hosts to all half-duplex mode? that way, they'll 'behave' better when
trying to force their way thru the switch, so to speak.
: How are these *supposed* to work? I though I needed a switch to do this
: right (and from the looks of things, I may be right) but can anyone give me
: a clue?
switches are expensive. that hubbie is about $100, right? its really
just a learning bridge with two repeated segments (a 10 and a 100).
when you have collisions on the repeated segment, data is lost and NOT
buffered. its cheap and it works for light traffic. for more dense
traffic, you should get a real multiport bridge (not the 2port bridge
with lots of PHY ports, like that hubbie thing).
: (Everything is set to half-duplex. Client type doesn't matter -- Linux,
: Win95, WinNT, Solaris, TCP/IP printer, etc.)
so its not a software issue, its at the MAC layer. what happens if
you connect a single 10 and a single 100 station. does the hub *
out then?
--
Bryan
by