4 replies to this topic

[Nevyn]

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

[Chris Walker]

Hi Nevyn, You're probably alright with both. I would try both, and see which one gives you better performance. TCP packets are about 1.5KB, but the data is also buffered internally. Chris

[Illishar]

The MTU (Maximum Transmission Unit) is often around 1500. It would be nice to know the exact value for the Netduino though.

[Jarrod Sinclair]

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

[nlatin]

How to change mtu size? I am using gsiot library?