[e2e] tcp connection timeout

David Borman david.borman at windriver.com
Tue Mar 7 12:38:17 PST 2006

Hi David,

On Mar 7, 2006, at 9:30 AM, David P. Reed wrote:

> David Borman wrote:
>> But it is valuable to know that the transport connection is down,  
>> and when the keepalive triggers a TCP RST, then it is providing a  
>> useful service.  No sense in hanging onto the phone if the other  
>> side has hung up.
> David - you obviously missed my note that started this part of the  
> discussion.  TCP connections are NOT phone calls.  They are NOT  
> hung up in that way (a CLOSE is sent as part of disconnection).    
> They don't tie up wires, they don't tie up routers, they don't tie  
> up bandwidth.  Reasoning about phone calls adds nothing to this  
> discussion.   Might as well think about the analogy to alligator  
> wrestling for all that helps.

I know how TCP works. :-)  I only referred to a phone call as it was  
already used as an analogy in a previous message.  My apologies if  
that muddled up my message.

My only point is that keepalives also can elicit an active response  
in the form of a RST for idle connections where the other side has  
terminated abnormally, or gone away during a period of network  
outage; they are not just about killing perfectly good idle  
connections due to lack of a response, but that's what everyone  
focuses on.

I'll be the first to say they have a very limited scope/purpose, and  
shouldn't be used beyond that.

			-David Borman

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