Hi Adam, It has been a couple of days and no response on this Q so I will relpy.
First, you have done your homework well. I have not used the TCP functions from Sheldon Instruments so I can not comment on that. I think the Naegel option would help if you were send alot of small packets that need individual resposnes. I am a bit concerned about your target of 30mbps. It has been years since I dug this low but I think 30mbps is going to be the upper limit of a 100Mbps LAN. This is based on the "old days" when ethernet ran over coax. The issue as I see it is how the hardware gets access to the LAN. Ethernet adapters have to do a number of things when transmitting a packet. First it has to check the network to see if anyone else is talking. If the network is free, it will then transmit the data while simultaneously read from the network. If another node is trying to do the same thing at the same time, they will corrupt each others transmission resulting in a bad CRC being detected by each transmitting node. This is a collision. The interfaces are then supposed to execute a random wait and then retry. You probably new this already. When the network utilization is low, collisions are less likely and data can fly. Once the network utilization starts to climb, the collisions become more frequent and over-all throughput will decline. In the "old days" we used to recomend trying to keep utilization below 30% of the theoretical max. This is why I am concerned about you trying to do 30mbps over a 100mbps LAN. You are right on the edge where performance starts to drop off. Remember that TCP packets are ack'd by the reciever! This ack'ing is going to introduce collisions because this has to happen to support the integrety of the transmision. Enough about me fears, how about some ideas. First; Keep LV out of the mix and just try your hardware and OS out using file transfers. Just try copying large files from one machine to the other on your dedicated LAN. If you can transfer files at 30mbps, then you may be able to do the same with an app in LV. (Note File sharing is generally implemented using TCP/IP). Second; I think you probably will have to go for the 1Gig route. Your 30mbps is only 3% of that bandwidth so provided your hardware can pump as fast as the net can suck, you should be able to pull this off. In closing I would like to clearly state that I am not an expert in this area and it has been years since I got into the low-level details, so please forgive me if I have got something wrong here. I will watch this Q to see how things work out for you and see if anyone else would like to jump in here and straighten me out. Trying to help, Ben <a href="http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=261&HRedirected=True&HUserId=101_3529&RFORMNUMBER=6";>Ben Rayner</a> <a href=" http://volt.ni.com/niwc/common.jsp?page=products_certification_cld&node=10638";> Certified LabVIEW Developer </a> www.DSAutomation.com
