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Thanks Al for the tutorial. While you are in that mode, could you expand a little more on the timing aspects of TCP vs UDP? len -----Original Message----- From: Al Snell [mailto:alaric@a...] Ok, networking 101. TCP provides an emulation of a serial line, basically. UDP provides the raw network. UDP applications add their own packet-based retransmission code, or use an existing library like ONC RPC to do this for them. However, by doing this without doing it the way TCP does - which emulates a serial line as well - they do it more efficiently. As I said before, TCP will ensure that data arrives in order, which is often undesirable, and it will hide packet boundaries, which is often undesirable. It's annoying that there aren't many implementations of RDP or NetBLT around (see the RFCs), since they provide a nice middle ground between TCP and UDP, but when the things TCP does unacceptably screw up your system, you have to start with UDP and add retransmission (the most common requirement) to get it to work. The Internet would be horribly, horribly, slow to use if DNS worked over TCP rather than UDP... DNS uses TCP only for zone transfers, which are not time critical :-)
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