Asynchronous sockets and pooled thread loading

I'm working on a proxy which must support at least a dozen simultaneous
connections from local clients to remote servers. It is conceivable that
someone might want to run it in non-local mode, with as many as 3-4
dozen simultaneous connections from remote clients to remote servers.
Supporting that is desireable but optional. The proxy will have to
maintain
client/server connections for up to several hours, but the traffic will be
intermittent/bursty. I have no hard requirements in terms of performance.
The proxy does a bit of massaging of the messages that get sent through
it, and I haven't figured out the internal logic. But it isn't out of the
question
that I might want to do a BeginReceive and BeginSend on both the client
and server sides. Which would mean four "outstandin g" BeginX requests
per proxy * N proxies.

I understand that when a send or receive completes, the callback will be
executed on a some kind of pooled thread. I expect my callback routines
to be fairly lightweight... just some simple text processing, optional
debug
oriented logging, and accesses to a shared Hashtable for purposes of
recording/recalling that certain messages & events occurred. I have no
idea of what kind of load the callback/completion routines will put on the
system and can only hope for the best until I get some protocode up and
running or someone points out an obvious problem. What I'm mainly
concerned about ATM is whether the simple act of Beginning many
sends/receives could tie up too many pooled threads.

Could someone give me some sense of how these pooled threads are
actually used between the time a Begin is launched and the request
completes? For example, does a BeginSend cause a thread to be
allocated until all of the data can be written to the underlying socket's
send buffer and the send callback completes? Does a BeginReceive
cause a thread to be allocated only after data is available in the
socket's
receive buffer and until the receive callback completes? Thanks.

What I'm mainly
concerned about ATM is whether the simple act of Beginning many
sends/receives could tie up too many pooled threads.
No.
Could someone give me some sense of how these pooled threads are
actually used between the time a Begin is launched and the request
completes? For example, does a BeginSend cause a thread to be
allocated until all of the data can be written to the underlying socket's
send buffer and the send callback completes? Does a BeginReceive
cause a thread to be allocated only after data is available in the socket's
receive buffer and until the receive callback completes?

"User N" <Us***@invalid. invalid> wrote:

What I'm mainly
concerned about ATM is whether the simple act of Beginning many
sends/receives could tie up too many pooled threads.
No.

[]
And indeed .NET async. sockets demonstrate unbelievable performance
in practice.