Re: [nslu2-general] Re: I need a hint (or several)...
- At 03/01/2005 07:47 PM, you wrote:
>I have searched for "optimistic locking" with Google but did only findSorry, that was opportunistic locking. You're right, optimistic locking is
>that term in connection with Access (or other SQL-type) databases.
a database term.
>I have implemented a couple of MS "knowledge base" tips with *no result*.That's what you can expect from MS :-)
Try 296264. I haven't tried it yet, so no guarantees.
"All I wanna do is have a little fun before I die" Sheryl Crow
- On 1/3/2005 1:36 AM EST, unix fan wrote:
>Actually, a good switch would be better than a crossover cable. I
> You forgot about the box in the middle, your router or switch. What
> is it?
> It's quite possible the connection to the NSLU2 has been incorrectly
> autonegotiated with a mismatched duplex setting. Even high end Cisco
> routers and Sun Workstations have this problem. That trashes the
> network connection (lots of errors). I don't know how you can tell
> what the router/switch port duplex setting is. But if you want to
> probe at the problem, go buy a crossover cable and connect the NSLU2
> directly to your computer's NIC )i.e., the RJ45 port. That would at
> least get the router and the cabling to it out of the equation.
believe that full duplex communications require either forcing on both
ends, or auto-negotiating with a NWAY hardware switch. One PC to
another PC will likely not autonegotiate to 100Mbps full-duplex (may
only be half duplex). If autonegotiations does not occur, the default
behavior is to use forced half-duplex.
You are right, though, that the wrong negotiations will cause all sorts
of errors (and obviously collisions), which would cause excessive
retransmissions and thus lower throughput.
Most people don't have routers; they are called broadband routers but
they are nothing more than a network switch connected to some ARM or
equivalent processor for filtering and NAT to the WAN port.
In regards to cabling, to ensure you're using the right kind of cable,
you can do the following:
Holding the cable in your hand with the tab sticking down and the the
RJ45 connector pointing away from you as if you were going to plug it
into a jack, pin 1 is the leftmost wire on the RJ45 connector. Check
that the wires for pins 1 and 2 are opposite colors. I.e., if pin 1 is
white with orange stripe, pin 2 should be orange with white stripe. Do
the same for pins 3 and 6. If this is fine on both ends, then your
cable is fine. I have seen some RJ45 connected cables made for digital
phones that don't require the CAT5 / T568B (I think) wiring
specification. It will work for 10Mbps but at 100Mbps it causes an
excessive amount of crosstalk that can mess up a lot of ethernet
switches and hubs. I have seen it for myself.
Hope that helps.