?
Solved

Is 100Mbps Full Duplex

Posted on 2009-12-24
13
Medium Priority
?
1,320 Views
Last Modified: 2012-06-21
  This is like a newbie question and I feel like an idiot but here is the story. I got in to a discussion in a round about way questioning a manufacturers 802.11N throughput spec of 150Mbps. He said that 802.11N is half duplex and it is rated at 75Mbps one direction and that the 150Mbps is the sum of both directions. My understanding is that since you can get 75Mbps in half duplex mode that running is full duplex mode will give you 150Mbps total throughput.

   OK. I guess that makes sense but how is 100BaseT or even Gigabit rated. Is the 100Mbps in one direction so in essence when you run it full duplex you actually get 200Mbps total throughput?
0
Comment
Question by:jimbecher
  • 4
  • 3
  • 3
  • +2
13 Comments
 
LVL 3

Expert Comment

by:Wartickler
ID: 26120673
Ful Duplex means that the switch/router can do both 10 and 100. Off the top of my head I don't know if that applies to 1000...

Happy Holidays!
0
 
LVL 11

Author Comment

by:jimbecher
ID: 26120685
  That doesn't answer the question. Full Duplex means it can transmint and receive at the same time. So when you say my network is running 100Mbps what exactly does that mean? is it 50Mbps in each direction for a total of 100Mbps or is it 100Mbps each direction for a total throughput of 200Mbps?
0
 
LVL 4

Expert Comment

by:imadimad
ID: 26120688
Full Duplex means that upload is equal as the download so 100Mbps full duplex is 100Mbps for upload and 100Mbps for download.

Regards,
0
Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

 
LVL 3

Expert Comment

by:Wartickler
ID: 26120691
lol

Clearly, I am not an expert at networking (:

I would assume that means it will handle 100 both ways, but I am not an expert. I'll let someone else take this one!
0
 
LVL 4

Expert Comment

by:TechForce
ID: 26120700
see: http://www.tech-faq.com/half-duplex-full-duplex.shtml for quite a bit of info regarding half and full duplex.
0
 
LVL 11

Author Comment

by:jimbecher
ID: 26120702
  I need you to be a little more specfic imadimad. It is a known that half duplex is a one direction only and that full duplex is transmitting in both directions at the same time.

   So the rating of "100Mbps" is in each direction (full duplex) to a "total" throughput of 200Mbps?
0
 
LVL 4

Accepted Solution

by:
imadimad earned 2000 total points
ID: 26120709
Yes, the total is 200Mbps. In full duplex they are in fact two independent lines.

Regards,
0
 
LVL 3

Expert Comment

by:Wartickler
ID: 26120710
http://www.intel.com/support/express/switches/sb/cs-014409.htm

Quote:
Full duplex switching is a very simple way to improve server performance. Bandwidth is improved to the server since both transmission and reception can occur simultaneously. If server reads and writes are symmetric, 200 Mbps bandwidth can be realized. In actual usage, bandwidth improvements are more modest.
0
 
LVL 11

Author Comment

by:jimbecher
ID: 26120722
  Thanks imadimad. That was the question. The 100Mbps spec I guess you could say would be understated. You can actually get 200Mbp across the line in one second.

   I guess 802.11N is stated differently. The above manufacturer "advertised" the wireless as being "150Mbps" when it should have been 75Mbps. I guess that is the difference between wireless and wired.
0
 
LVL 4

Expert Comment

by:TechForce
ID: 26120724
it is 200mb, theoretically, you can achieve a max of 200mb, however its THEORETICAL, i've never tested it, but don't expect to see it happening consistantly i guess.
0
 
LVL 4

Expert Comment

by:imadimad
ID: 26120746
The term is same for both wire and wireless. However, this is theoretically in both cases and the wireless loses a lot more packets than the wired connection.
0
 
LVL 11

Author Comment

by:jimbecher
ID: 26120781
  Thanks guys but I don't want to get off track. We all know about collisions, retries, packet loss, etc. I want to stick strickly with the "advertised" throughput.

    So from what I have been able to put together so far the advertised throughput is directly related to the type of network you are talking about. Wired vs Wireless.

   The 100BaseT spec advertises 100Mbps but that is a half duplex advertisement. If you run Full Duplex then it becomes 100Mbps in both directions at the same time for a total throughput of 200Mb in one second correct?

   What I am being told (as stated in the initial question) is that 802.11N does it completely different. The manufacturers rating of 150Mbps is total. 75Mbps half duplex or 150Mbps Full Duplex. A total of 150Mb in one second. FYI it is low because it is in the 5Ghz band over a really long distance.

   You can carry this 802.11N "advertising" to what most wireless manufactures advertise as 300Mbps. It is really 150Mbps in each direction at the same time for a total throughput of 300Mb in one second.

   Can anyone confirm of deny my understanding?

0
 
LVL 6

Expert Comment

by:peter41
ID: 26122424
" The 100BaseT spec advertises 100Mbps but that is a half duplex advertisement. If you run Full Duplex then it becomes 100Mbps in both directions at the same time for a total throughput of 200Mb in one second correct?"

Yes, fast ethernet (normally called 100Mbit ethernet) when run in full-duplex mode,
can have total throughput 200Mbit per second. In full-duplex mode, network card uses one twisted pair of wires  for sending data (100Mbit/sec upload) and second twisted pair for receiving data (100Mbit/sec download).

Second question:
I dont know what manufacturers means by 300Mbit/sec. To answer there must be known 802.11n and MIMO standards, I am not expert in this area, sorry.

Peter
0

Featured Post

 [eBook] Windows Nano Server

Download this FREE eBook and learn all you need to get started with Windows Nano Server, including deployment options, remote management
and troubleshooting tips and tricks

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A common practice in small networks is making file sharing easy which works extremely well when intra-network security is not an issue. In essence, everyone, that is "Everyone", is given access to all of the shared files - often the entire C: drive …
This is the first one of a series of articles I’ll be writing to address technical issues that are always referred to as network problems. The network boundaries have changed, therefore having an understanding of how each piece in the network  puzzl…
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…
Despite its rising prevalence in the business world, "the cloud" is still misunderstood. Some companies still believe common misconceptions about lack of security in cloud solutions and many misuses of cloud storage options still occur every day. …
Suggested Courses
Course of the Month17 days, 6 hours left to enroll

864 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question