If you had a wired network, 20 PCs hooked up to a 100 Mbit/sec switch (same onboard ethernet port speed) and you were just sending some test data round. What is the technical explanation as to why 20 machines sending test data around this network to each other is slower than one to one?
I mean I know a busy network means it’s slower but I’m really trying to understand some more technical details.
Thanks for any help
Answer
Transmission will be constrained by the slowest link. Assuming all devices are 100mbps capable and running full duplex:
- 10 clients to one server may have a 10 Mbs average transfer rate for each client (constrained by servers link). Overall data rate will not exceed the 100 Mbs transfer rate of the server’s link.
- 10 pairs of hosts may have 100Mbs transfer rate for each pair (slower rates may be a result of capacity limits on the switch). Overall data rate will not exceed the capability of the switch, but could be as high as 1 Gbps.
Other factors normally constrain the data rate. Data transfer rates will be the slowest of the rate the source can provide the data and the rate the target can consume the data. Switches may not be able to transfer data between all ports at the full rate.
In most configurations many ports transfer data at rates well below the speed of the link. Faster links may still be desirable as the link latency will be lower. A 1200 byte packet will take roughly 1 millisecond per hop on 10 Mbs links, 0.1 millisecond on a 100 Mbs link and, only 0.01 millisecond on a 1 Gbs link. There will be additional latency in transfer due to buffering, distance, and speed of transfers within devices.
Attribution
Source : Link , Question Author : Ed Briscoe , Answer Author : BillThor
