c2523f52
XPost: comp.arch.embedded, comp.os.linux.networking
From: barmar@alum.mit.edu
In article
<597a7568-ddf4-43af-bff0-fb22d0dddb37@m35g2000prh.googlegroups.com>,
karthikbalaguru wrote:
> While reading about the various designs, interestingly i
> came across an info that the design of TCP servers is
> mostly such that whenever it accepts a connection,
> a new process is invoked to handle it .
> But, it seems that in the case of UDP servers design,
> there is only a single process that handles all client
> requests. Why such a difference in design of TCP and
> UDP servers ? How is TCP server able to handle
> large number of very rapid near-simultaneous connections ?
> Any ideas ?
TCP is usually used for services that require a large amount of
interaction between the client and server, and state that must be
maintained for the duration of the connection. Forking a process or
spawning a thread provides an easy way to maintain that state, and keep
other connections from interfering. And since the connection is likely
to be maintained for a significant period of time, the overhead of
forking a process is usually negligible.
UDP is generally used for simple request/response protocols, where each
packet is independent and state doesn't need to be maintained. Speed is
often of the essense, so having to fork a process for each request would
slow things down noticeably.
There are exceptions, though. If a server handles hundreds or thousands
of concurrent connections, forking so many processes is likely to
overload the system. Thread pools are often used for these types of
servers.
--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***
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