Heo, Have a look at <http://www-ece.rice.edu/~jpr/ns/docs/ns-802_11b.html>. It answers your direct questions.
You may also wish to look at <http://www.telematica.polito.it/fiore/index.html#downloads> if you're interested in adjustments to simulate more recent chipsets accurately. Phil On 7/22/06, Heo Heo <[EMAIL PROTECTED]> wrote: > > Hi all, > > I was doing a simple wireless simulation in which 2 nodes send are > placed next to each other, with one being the sender and the other being > the receiver (based on the Simple.tcl on ns website). The sender sends > 500 packets to the receiver. > > 1) I tried to change the packet size from 512 to 1024 bytes. I parsed > the trace file I find out that: > - If the packet size is 512 bytes, 500 packets were sent. > - If the packet size is 1024 bytes, 1000 packets were sent. > > It seems to me that some layer has automatically split up the 1024-byte > packets > into smaller parts. > > So, my question is: what is the default wireless packet size, and how > to change it ? and Which layer actually split up the big packets ? > > 2) My next question is about the wireless bandwidth. > > By default, ns uses a wireless link bandwidth of 2 Mbps. By > changing the packet interval, I have at most 670 Kbps. Because there are only > 2 nodes, the 2 nodes must be using full bandwidth for this. Given that > there are some overhead (RTS/CTS, packet headers, etc.), I would think > I should get about 1.5Mbps. So, why is the actual speed so much lower > than that ? Is it natural ? > > Thanks a lot for your help. > > Heo
