Point to point communications over 100baseT

Jan 19, 2005 4 Replies

I have a requirment to communicate between 2 PC's over a point to point connection at 33Mbps. Other then LVDS what comm protocal supports these speeds? (I know USB does, but I have not found a USB hosthost bridge that supports those speeds.) I know ethernet does, but I've never seen it used in this manner. Is it possible to directly connect 2 machines with a 100baseT cable and just talk to each other without TCP/IP? Is there software that supports such a beast?



Thanks!



-larry


In article , Larry Martell wrote: :I have a requirment to communicate between 2 PC's over a point to :point connection at 33Mbps.

:Is it :possible to directly connect 2 machines with a 100baseT cable :and just talk to each other without TCP/IP?

Yes.

:Is there software that supports such a beast?

Is there a particular need for it to not be TCP based? If so is there also a requirement that it not be IP based? 33 megabits per second of payload is well within the capabilities of any modern TCP or IP stack.

In any case, you can write out raw ethernet packets, and the other end can read raw ethernet packets. You'll have a little bit of difficulty in getting the receiver's NIC to accept the packets. I suggest that you look at 'libpcap' which is well able to do the appropriate setup for capturing arbitrary packets.

Sure, just use a crossover cable instead of a straight through cable. What distance do you need to do this at? If you are talking more than the hundred meter limit of UTP without a repeater, then you start to hit a bunch of issues that make it way more expensive. You do need a good set of NICs, preferably matching ones to reduce finger pointing from vendors blaming the other guy rather than solving problems.

--Dale

100 Mbit/s comes to my mind first.

Sure, just use a crossover cable instead of a straight through cable. With a crossover cable you can connect two PCs directly to each other. I have done this many times.

Ethernet and TCP/IP usually come together. But there is no need to use TCP/IP protocol with Ethernet. Ethernet can support many different protocols, and with suitable software you can just send and receive "raw" Ethernet packets.

If you're talking more than 100 meter, you can either go to fiber-based Ethernet solutions (100BASE-FX/LX10/BX10), or to 10PASS-TS.

10PASS-TS will give you (more than) 33 Mbps over several hundred meters of voice-grade twisted pair. It is part of the recently approved "Ethernet in the First Mile" standard (IEEE Std 802.3ah-2004) and is based on VDSL. There are proprietary (pre-standard) solutions available on the market as well.

Michael (remove "filter" from email address)

formatting link

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required