24 devices to single pc

[skjomcs 0]

i am trying to design a network where there are 24 microscan hawk barcose readers that are transmitting their decoded strings to a single windows xp pc. A software program collects the read strings on the pc. i.e. the 24 devices read the seperate barcodes potemtially at the same time and transmit the read strings (24 numeric digit string) to the pc. (350 reads a minute) My first thoughts would be connect the devices to a switch then connect the switch directly to the PC. the devices would be arranged in a star pattern to the switch, with the single connection from switch back to the pc. however would there be a potential bottleneck going into the PC? would the pc cope wit the data without dropping the strings? would it be better to use a few nic's to distrube the load? Any suggestions on how to design this are welcome Thanks

[J. B. Jennings 4]

What is the model/part number of the Microscan Hawk? I have used up to 4 of these in a system in the past with no problem, even with concurrent readings. 24 may be a stretch. How often would more than one scanner be processing (scanning) a barcode? What type of application are you using these sensors? More Information==Better Answers

[billysmithde2 1]

Here are some calculations to look at network loading: 24 devices x 350 reads/min/device = 8400 reads/min = 140 reads/sec which gives 7.1ms/read Assume each read is a TCP/IP packet on ethernet of about 78 bytes: minimum TCP packet size (as we would see with an ACK only, no data) is 54bytes, so 54 min bytes + 24 bytes of message = 78 bytes and this is greater than minimum standard of 64 required by ethernet, so we go with 78 bytes/packet. 8400 reads/min x 78 bytes/read = 655 200 bytes/min = 87 360 bits/sec = 0.09 Mbit/sec This assumes one packet per read - not really true - we need to at least ACK the TCP data, and I don't know if you need a read request. So conservatively, if you triple the above data calculations then that is your required network throughput. Request -> data -> ACK so 3x0.09Mbit/sec is say 0.3Mbit/sec. Your running 100Mbit full duplex (assumption)... 0.3 <<< 100 so network load won't be a problem for you. Next step - can the software package reading this data handle this many connections and data this fast? If my assumptions are wrong, just substitute the correct numbers and recalculate.