> > Hio, > > I posed these ques in different forums, but did not get any > satisfactory > reply. I know this is not the best stage to raise these ques, but i am > sure any serious network software developer would be > interested in these > at some point of time... Now the ques. > > 0. *WHY* the *minimum* ethernet frame size is 64 bytes. Any rational > behind this? This means that *at-least* 46 bytes of data *must* be > present in the ethernet frame. (Even if there is not much > data, that > *must* be appended with zeros to make it 46 bytes). The minimum length is fixed by physical problems like transmit time of a paquet and collision detection on the wire by the ethernet adapters. (at least i believe this until someone tells me something else acceptable). ie: if you send a too small paquet that comes into collision with another, you take the risk that other adapters won't see the collision. This depends on three things: the length of your paquet, the speed of data in the wire, the distance between the adapters on the wire. The speed is known, the RFC gives a limit in both minimum length and maximum distance between the adapters so that if you respect these limits you know that your network will work. > > 1. *WHY* is a pseudo header used for calculating checksum in TCP/UDP > headers. Is this not a overhead. Any specific reasons for > this? RFCs > are silent on this. don't know and don't have time to look... > > If any one could point out some links, which shed more light on these, > that would suffice. I've already searched the net and various mailing > list archieves for the above questions without success. > Thanks in advance > for any replies. > > Sharad. pascal -------------------------------------------------------------------- The Linux India Mailing List Archives are now available. Please search the archive at http://lists.linux-india.org/ before posting your question to avoid repetition and save bandwidth.
