Date: Fri, 04 Jun 1999 11:20:34 -0700 From: "Kevin J. Rowett" <krowett@rowett.org> To: Matthew Dillon <dillon@apollo.backplane.com>, David Malone <dwmalone@maths.tcd.ie> Cc: Poul-Henning Kamp <phk@critter.freebsd.dk>, current@FreeBSD.ORG Subject: Re: net.inet.tcp.always_keepalive on as default ? Message-ID: <4.2.0.56.19990604111235.00ae3ac0@rowett.org> In-Reply-To: <199906041703.KAA08090@apollo.backplane.com> References: <9906041725.aa11603@salmon.maths.tcd.ie>
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At 10:03 AM 6/4/99 , Matthew Dillon wrote: > I think people just like to argue sometimes. The reality is different. > > For all you people complaining: Just turn them on and I guarentee > you will not even notice the difference, except you will stop getting > ( even the occassional ) stale internet server process. That is what > keepalives were designed to deal with. Keepalives are not supposed to > be a network watchdog, they are simply supposed to be a catch-all. This seems to be rather end-user, and short sighted. TCP and the underlying Internet has survived, and been able to scale (among other things), because of the work of many to balance end-user performance and overall network performance. All the TCP congestion avoidance algorithms and work done go towards managing a shared medium without a central point of control. If this work had not been done, then the Internet would not have grown as it did today. The central issue of keepalives is that, for one machine, they don't create a significant load. Multiplied by the number of machines on the Internet, it can become a problem. If freeBSD makes it a default, then other will adopt as well. Some less experienced and clueful implementors won't do as good a job with the overall TCP implementation, and we might see keepalives being sent every TCP timeout, for every connection, as a way to deal with a protocol error. :-) KR To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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