Full or half duplex?

[dlr21 0]

hi all,

 

i have been set the task of implementing a gigabit ethernet lan, gigabit all the way to the desktop (about 400 users) could someone tell me if i should use full or half duplex ? i read somewhere that there isn't any equipment available for half-duplex. can someone help?

 

Cheers,

 

Dan.

[ScinteX 0]

I would imagine that there isnt actually a choice to be made- set everything to "auto".

 

If you're running gbe all the way to the desktops you actually have less of a potential problem

 

You could have 3 different speeds on a network: 10 Mbps, 100 Mbps, and 1000 Mbps. Cos of this, the IEEE developed a method known as auto-negotiation to eliminate the possibility of dissimilar technologies interfering with each other.

 

If you set everything to auto then if you do end up with a device thats operating at 10/100/half/full then they will work out for themselves what the best operating speed/mode is.

 

This can be a very technical subject so I wont harp on lol

 

 

 

[zen69x 0]

Actually, from my understanding, if you set it to auto and there is a mismatch, you will default to 10Mbp/s half duplex.

 

You should only run full duplex if you have only 1 device off of each switch port. In other words, if you have the possibility of a collision (2 devices sending on the same wire at the same time) occurring on the port, you should run half duplex.

 

Hope that helps.

[DS3Circuit 0]

Figured I would add my $0.02 into the fray.

 

So we are all on the same page, realize that Half Duplex is like a walkie talkie and Full Duplex is more like a phone line.

 

When going from distribution network stacks to the desktop, my organizations go with the principal of using auto detect, as if collisions occur, a user's environment is generally minimally affected.

 

When interconnecting devices between core vlans, legacy equipment, heterogeneous equipment, and servers, we pin the nic speed and duplex as well as on the port side. We have found better throughput on backups, trunking, and jumbo frames implementation when doing so.

 

If I missed anything, Im sure someone will chime in.