W dniu 19.12.2024 o 05:04, Jim Carpenter pisze:
On Wed, Dec 18, 2024 at 4:26 PM Radoslaw Skorupka
<[email protected]> wrote:
A comment regarding no loop. It is 1000BaseT port. It is physically
impossible to connect two LAN cards without the switch.
Yes, for older 10BaseT or 100BaseT (10Mbps or 100Mbps respectively) it
was possible to use special "crossed" cable to connect Tx to Rx and vice
versa. However not for gigabit connection.
It is completely not mainframe-specific issue, it is just Ethernet.
Sure you can. I connected at 1Gbps two PCs without a switch about a
hour ago. A crossover cable would have worked but was not needed. Auto
MDI/MDI-X is part of 1000BaseT and optional but common for 100BaseT
devices. I have not needed to use a crossover cable since the 10BaseT
times.
I could swear I read an article about 1000Base-T clearly saying the
communication is possible only through a switch.
Of course Auto MDI/MDIX feature eliminates the need of crossover cables,
but it is a little bit more complex because 1000Base-T use all 4 pair in
duplex mode so there is no more "Tx to Rx connection". In fact I was
focused on the channel throughput and other transmission issues related
to the increased speed (read: how does it work), but I noticed the
switch is always required.
Of course since you just connected two PCs without a switch the
information about above seems to be false. Thank you for clarification.
BTW: several years ago a switch was quite expensive. Nowadays one can
buy it for peanuts, so the cost is no longer relevant.
--
Radoslaw Skorupka
Lodz, Poland
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [email protected] with the message: INFO IBM-MAIN
