Subject: Re: [RFC PATCH net-next] tcp: introduce tcp_tw_interval to specifiy the time of TIME-WAIT

From: Rick Jones <[email-masked]>
Date: Fri, 28 Sep 2012 10:30:27 -0700

On 09/27/2012 11:43 PM, David Miller wrote:
> From: Cong Wang <[email-masked]>
> Date: Fri, 28 Sep 2012 14:33:07 +0800
>
>> I don't think reducing TIME_WAIT is a good idea either, but there must
>> be some reason behind as several UNIX provides a microsecond-scale
>> tuning interface, or maybe in non-recycle mode, their RTO is much less
>> than 2*MSL?

Microsecond?  HP-UX uses milliseconds for the units of the tunable, 
though that does not necessarily mean it will actually be implemented to 
millisecond accuracy

> Yes, there is a reason.  It's there for retaining multi-million-dollar
> customers.
>
> There is no other reasons these other systems provide these
> facilities, they are simply there in an attempt to retain a dwindling
> customer base.
 >
 > Any other belief is extremely naive.

HP-UX's TIME_WAIT interval tunability goes back to HP-UX 11.0, which 
first shipped in 1997.  It got it by virtue of using a "Mentat-based" 
stack which had that functionality.  I may not have my history 
completely correct, but Solaris 2 also got their networking bits from 
Mentat, and I believe shipped before HP-UX 11.

To my recollection, neither were faced with a dwindling customer base at 
the time.

rick jones