Re: [BEHAVE] [v6ops] Home NAPT44 - How many ports?

Owen DeLong <owen@delong.com> Thu, 06 June 2013 22:57 UTC

Return-Path: <owen@delong.com>
X-Original-To: behave@ietfa.amsl.com
Delivered-To: behave@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id D30CB21F99FE; Thu, 6 Jun 2013 15:57:59 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.239
X-Spam-Level:
X-Spam-Status: No, score=-2.239 tagged_above=-999 required=5 tests=[AWL=-0.240, BAYES_00=-2.599, J_CHICKENPOX_13=0.6]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id VPiWlS0SnTV3; Thu, 6 Jun 2013 15:57:58 -0700 (PDT)
Received: from owen.delong.com (owen.delong.com [IPv6:2620:0:930::200:2]) by ietfa.amsl.com (Postfix) with ESMTP id B19E821F99FC; Thu, 6 Jun 2013 15:57:58 -0700 (PDT)
Received: from [10.255.251.221] (kiwi.he.net [216.218.252.66]) (authenticated bits=0) by owen.delong.com (8.14.2/8.14.1) with ESMTP id r56Ms3Pv023866 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT); Thu, 6 Jun 2013 15:54:03 -0700
X-DKIM: Sendmail DKIM Filter v2.8.3 owen.delong.com r56Ms3Pv023866
DKIM-Signature: v=1; a=rsa-sha1; c=simple/simple; d=delong.com; s=mail; t=1370559244; bh=XOC6aJPR8ro+Jbb4/SAmvP7Hdu4=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Content-Transfer-Encoding:Message-Id:References:To; b=SA5hoKDz17nUDDu819T+QXxURVg5vDL6MxfHNWI2gsuqSHcSGDm/wA3Bb94VfGyU8 tL5lZTfbrlcaBGAGXRjAcv5/YVd0nGFE0vlw/lzdO+B+zdlLrdU6Eh6ST6dPVsGHbD 6ZDn11/OSpdj/4GNhZuoviIC8FSIQJ5C8c1YDXrQ=
Content-Type: text/plain; charset=us-ascii
Mime-Version: 1.0 (Mac OS X Mail 6.3 \(1503\))
From: Owen DeLong <owen@delong.com>
In-Reply-To: <B14A62A57AB87D45BB6DD7D9D2B78F0B116D8383@xmb-rcd-x06.cisco.com>
Date: Thu, 6 Jun 2013 17:54:13 -0500
Content-Transfer-Encoding: quoted-printable
Message-Id: <2FB6F4EA-F632-43E1-B7ED-A13338610746@delong.com>
References: <B14A62A57AB87D45BB6DD7D9D2B78F0B116D2400@xmb-rcd-x06.cisco.com> <FC155739-3CB3-48FD-B77A-8526BEE9648B@cisco.com> <B14A62A57AB87D45BB6DD7D9D2B78F0B116D8383@xmb-rcd-x06.cisco.com>
To: "Rajiv Asati (rajiva)" <rajiva@cisco.com>
X-Mailer: Apple Mail (2.1503)
X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0rc1 (owen.delong.com [192.159.10.2]); Thu, 06 Jun 2013 15:54:04 -0700 (PDT)
X-Mailman-Approved-At: Fri, 07 Jun 2013 08:57:20 -0700
Cc: "Softwires-wg list \(softwires@ietf.org\)" <softwires@ietf.org>, "v6ops@ietf.org" <v6ops@ietf.org>, "behave@ietf.org" <behave@ietf.org>, "Dan Wing \(dwing\)" <dwing@cisco.com>
Subject: Re: [BEHAVE] [v6ops] Home NAPT44 - How many ports?
X-BeenThere: behave@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: mailing list of BEHAVE IETF WG <behave.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/behave>, <mailto:behave-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/behave>
List-Post: <mailto:behave@ietf.org>
List-Help: <mailto:behave-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/behave>, <mailto:behave-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 06 Jun 2013 22:58:00 -0000

At the point where we start calling any form of NAT "non-degraded" service, we have already strayed so far from rational thought that it is difficult to believe any rational conclusion can come from it.

ANY NAT is a degraded service. More NAT is inherently more degraded, even if it doesn't suffer an additional lack of available port numbers.

Owen

On Jun 6, 2013, at 5:41 PM, "Rajiv Asati (rajiva)" <rajiva@cisco.com> wrote:

> Hi Dan,
> 
>> and so on.  I am surprised you conclude that "500 seems ok" when such a
>> limit would interfere with your network use on those days.
> 
> I based that statement ("...seems ok,") on the very fact that the number of times the NAT utilization exceeded 500 mappings (equating to 500 ports, in my setup) in the sample period (~2 months) was relatively quite low. So, if the NAT device was limited to only 500 mappings, then the experience would have been ok for 99% of the time and degraded 1% of the time. This is an important consideration, IMO.
> 
> For ex, in the last 2 weeks, the number of times NAT mappings exceeded 500 were:
> 
> June 3 - 1 time
> May 29 - 1 time
> May 28 - 3 times
> May 26 - 1 time
> May 23 - 1 time
> May 22 - 2 times
> May 21 - 3 times
> 
> Of course, 1000 ports (resulting in 1000+ mappings) would have been more than enough to accommodate the times when the mappings exceeded 500, but stayed within 1000 (except once).
> 
> 
>> What is the maximum number of mappings supported by your NAPT device?
>> Some residential-class NATs have a limit of 1024 mappings.
> 
> My NAPT device seemingly can use upto 64K ports. :)
> 
> Cheers,
> Rajiv
> 
> 
>> -----Original Message-----
>> From: Dan Wing (dwing)
>> Sent: Thursday, June 06, 2013 11:43 AM
>> To: Rajiv Asati (rajiva)
>> Cc: v6ops@ietf.org; Softwires-wg list (softwires@ietf.org);
>> behave@ietf.org; Erik Kline (ek@google.com)
>> Subject: Re: [BEHAVE] Home NAPT44 - How many ports?
>> 
>> 
>> On Jun 5, 2013, at 6:14 AM, Rajiv Asati (rajiva) <rajiva@cisco.com> wrote:
>> 
>>> Some of you may recall our discussion (during the last IETF) around "how
>> many TCP/UDP ports are enough with NAPT44" per home, as ISPs move into
>> A+P paradigm. ~500, ~1000, ~3000???
>>> 
>>> Well, I started monitoring my home router and plotting the NAPT44 port
>> utilization on a minute-by-minute basis. You may find it here -
>> http://www.employees.org/~rajiva
>>> 
>>> In short, port range of 500 seems ok, though 1000 would be more than
>> enough for my home.
>> 
>> I see several spikes in your data over 500 ports.  During those times,
>> applications would be unable to function (unable to get a port).  April 29/30
>> is a long time where that occurs very visibly, but there are shorter spikes
>> elsewhere such as on April 17 and April 18.  If you had only 500 ports on
>> those days, creating a new TCP mapping would have been impossible,
>> impacting ability to send or receive email, order books from Amazon.com,
>> and so on.  I am surprised you conclude that "500 seems ok" when such a
>> limit would interfere with your network use on those days.
>> 
>> What is the maximum number of mappings supported by your NAPT device?
>> Some residential-class NATs have a limit of 1024 mappings.
>> 
>> -d
>> 
>>> Suffice to say, this is just a sample representation, since the port
>> utilization would vary home to home, based on number of active devices,
>> type of applications, the degree of simultaneous device or application
>> usage etc.
>>> 
>>> If any of you are doing similar monitoring, then please share.
>>> 
>>> Cheers,
>>> Rajiv
>>> 
>>> PS: Thanks to Erik Kline, who explained (with sufficient details) how to use
>> google charting for my data. And thanks to Xun Wang & Shaoshuai Dai for
>> helping me out significantly.
>>> 
>>> PS: My home has 3-4 active devices.
>>> _______________________________________________
>>> Behave mailing list
>>> Behave@ietf.org
>>> https://www.ietf.org/mailman/listinfo/behave
> 
> _______________________________________________
> v6ops mailing list
> v6ops@ietf.org
> https://www.ietf.org/mailman/listinfo/v6ops