Newsgroups: comp.protocols.tcp-ip
Path: utzoo!utgpu!cunews!newbridge.com!todds
From: todds@newbridge.com (Todd Sandor)
Subject: UDP Reliability between processes on same host
Message-ID: <1991Mar28.220615.5501@newbridge.com>
Sender: todds@newbridge.com (Todd Sandor)
Organization: Newbridge Networks Corp.
Date: Thu, 28 Mar 1991 22:06:15 GMT

Please don't flame me, I know UDP is unreliable, but I have
a question concerning using UDP between processes on the
same host.  We are using Sun Sparcstations runing 4.1.1
and using UDP sockets to talk between processes on the
same machine.  I realize UDP is defined as being unreliable,
and that we may possibly experience:
- socket overflows or
- bad data length fields or
- bad checksums

but could we experience out of order packets or duplicate
packets.  For example, one the same host, process A 
and B are up and are bound to each other, process 
A sends 5 datagrams to process B,
will process B get these 5 messages and only these 5 messages
in the order that process A sent them?  I don't have access
to source, so I can`t check this out, hopefully someone can
tell me the answer.  This is the simple case, (this works as I've
tested it), but under extremely HIGH loads, would we run
into problems?


Also, would it make a difference if the host address we used
in bind() call was the "localhost" (address 127.0.0.1 from
/etc/hosts file, its the loopback device).
Theoretically using this as the host would be faster,
I think?, since it wouldn't have go through the routing
code in the kernel.  Can anyone give me any input to this,
is it a good thing to do?  How much faster would it be?

And finally, can anyone give me input into the robustness
of TLI under SunOS 4.1.1.  In the manuals it says that sockets
are sort of being phased out, was wondering if anyone has
any real experience using TLI?

/todds
-- 
Todd Sandor        Voice: (613) 591-3600 ext 1011 P.O. Box 13600
Newbridge Networks FAX: (613) 591-3680      600 March Road
Mail: todds@newbridge.com                   Ottawa, Ontario,Canada K1G 3Z4