Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!AHWAHNEE.STANFORD.EDU!dcrocker
From: dcrocker@AHWAHNEE.STANFORD.EDU (Dave Crocker)
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  SO_KEEPALIVE considered harmful?
Message-ID: <8905231641.AA25794@ucbvax.Berkeley.EDU>
Date: 23 May 89 14:57:06 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 18

The use of Keepalives is terrible, but sometimes necessary.  The key
word, here, is "sometimes".

The "terrible" is due to the fact that they add traffic to the net.  An
important point to keep in mind, with TCP connections, is that they may
span the globe, over thin wires.  Extra traffic can have a very serious
effect.  Further, they scale poorly.  The incremental traffic from one
connection may not be onerous, but what about 1000 connections?  Lastly,
of course, there is the small fact that there may be a charge for those
extra packets, such as may happen if one of the links along the path
is over a public X.25 network.

If the group proposing the use of Keepalives has already gone through the
exercise of convincing themselves that critical functionality will be
lost if they are not used, then I hope the next question was/is how
to minimize their use.

Dave