Jarrod Sinclair

Hello All,
This project is still in progress, but my son and I completed our first pass on testing the code so I wanted to go ahead and post it and will update it with the final code and build of materials as I complete them. The details for the project are at http://jarrodsinclair.wordpress.com/.

Here is the main timer:


Video I posted on my blog regarding the testing (EDIT: Sorry about the quality):
http://www.youtube.com/watch?v=tXiUx43sbdU

I don't have the cover on the timer yet. It came with a black one but I didn't like it so I am making one out of Lexan. Also the wires are sitting on my bench cause I am still working on the aluminium frame that will hold the IR LEDs and Photo Transistors. There are a buch of other pics, process diagrams, drawings, and video of this build at http://jarrodsinclair.wordpress.com/ where I am building a project page with detailed information on the build.

I've just been writing up the Sliverlight code I have recently written and doing so caused me to question one of my design decisions. I decided that given the limited resources (i.e. memory) on the N+ I would send data to the browser in 256 byte chunks. On reading this code It caused me to recall my TCP/IP network training which stated that TCP packets were about 1.7Kbytes.

My question is, am I being too conservative and would I be better sending the data in say 1.5Kbyte chunks?

Alternatively, is my memory failing and I'm having a grey moment

Thanks in advance,
Mark

If you want to make sure the Netduino (or another other device along the way) is not fragmenting your packets then set your data segments size to 1452. With overhead (48 bytes for TCP and IP headers ) this will result in a packet size of 1500 and your packets should not fragments as they go our over the internet. If you notice fragmentation (drop in performance or using network tools you see it) then drop your segment to 1444 and then your MTU will be 1492 and should support even legacy devices in your network path.

FYI - If you want to see if your getting fragmentation using tools ten you can get wireshark for free. Once installed on your computer you will either have to send traffic to / from the device from the computer that has wireshark installed and running or use an old ethernet ***HUB*** (not a switch) and the you can capture the packets going between the netduino and a separate web-server / client