Half vs Full Duplex

[ruddog]

An interesting point was brought up in video 1b, it was, Ethernet and Fast Ethernet where different in more then just speed.

10BaseT can only function in Half duplex mode.

100BaseT can function in both Half and Full Duplex mode.

1000BaseT assuming it functions in both modes.

This was something I had not heard before, meaning it was my misunderstanding 10BaseT was capable of Half and Full Duplex mode?

Please bear in mind typing these questions, and statements helps me reinforce what I have viewed on the videos and is the sole reason for posting comments.

[Biggles77]

An interesting read for you. http://en.wikipedia.org/wiki/10BASE-T

I haven't seen this particular Train Signal Lab video but it was the Network Adapter that dictated whether 10Base-T would run at Full or Half Duplex and not the cable itself. It may have been the instructor was conveying that the hardware that he was refering to would only run at Half Duplex.

The ability to run at half or full duplex is dependant on the network adapter and some of the cheap 10 meg NICs didn't offer that feature. Don't forget that Full Duplex has to be set on both ends of the cable for it to work in "full" Full Duplex mode (and the hub/switch also needed to function at Full Duplex as well). I would have to research Hubs but I wouldn't imagine they would run in Full mode since they were in effect a "broadcast" device. Server NICs were (and now are) set to Full Duplex so they can send and receive packets at the same time. A workstation often had a cheaper NIC so it could either send or receive but not both at the same time. The traffic demands on a workstation were not as intence as a Server.

One of the earlier 10meg NICs I purchased was an RTL 8019 ISA card. It has a utulity that needed to be run so you could set the card to Full as it came set as Half by default.

If this hasn't made much (or maybe) any sense, post back with further questions.

[ruddog]

That was interesting reading and I certainly find myself pondering what was read some years ago especially when it comes to areas I thought were understood. Here is where I got the idea 10BaseT was capable of both full and half duplex and you might have stated the answer in your response "some cards had this capability".

If you went into the setup for the card in question most often the setting was AUTO and here is where I saw the capability to change the mode to either Full or Half duplex mode.

Keep in mind this was before 100BaseT had wide spread usage. The idea whether this thought of 10 BaseT was in fact both is merely a method for my discussions to hold some form of legitimacy.:eek: