Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!xanth!nic.MR.NET!ns!jmh
From: jmh@ns.network.com (1606)
Newsgroups: comp.protocols.tcp-ip
Subject: KeepAlive
Summary: KeepAlive is good practice
Keywords: Reliability
Message-ID: <1409@ns.network.com>
Date: 23 May 89 21:02:32 GMT
Sender: jmh@ns.network.com (Joel Halpern 424-1606)
Reply-To: jmh@ns.UUCP (Joel Halpern 424-1606)
Organization: Network Systems Corporation
Lines: 18

Given that most extended networks are not 100% reliable, some form
of keepalive is needed to detect loss of connectivity.

If I have a telnet connection to a host, and then the network fails,
I would appreciate it if the remote host knew this and could
undertake appropriate cleanup activities.

The key question is how often KeepAlive signals should be sent, and
what interval without any should result in declaring the connection
dead.

As a separate issue, the TCP implementation of keepalive signals
is sufficiently confused and inconsistent as to make it an undeirable
solution to the problem.

Joel M. Halpern
Network Systems Corporation
jmh@nsco.network.com