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

"Rajiv Asati (rajiva)" <rajiva@cisco.com> Wed, 05 June 2013 18:58 UTC

Return-Path: <rajiva@cisco.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 6579221F9B84; Wed, 5 Jun 2013 11:58:05 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.999
X-Spam-Level:
X-Spam-Status: No, score=-9.999 tagged_above=-999 required=5 tests=[AWL=-0.600, BAYES_00=-2.599, J_CHICKENPOX_33=0.6, J_CHICKENPOX_83=0.6, RCVD_IN_DNSWL_HI=-8]
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 l9ST4iSDB90E; Wed, 5 Jun 2013 11:58:00 -0700 (PDT)
Received: from rcdn-iport-5.cisco.com (rcdn-iport-5.cisco.com [173.37.86.76]) by ietfa.amsl.com (Postfix) with ESMTP id B179121F9C14; Wed, 5 Jun 2013 11:57:06 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=2526; q=dns/txt; s=iport; t=1370458627; x=1371668227; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-transfer-encoding:mime-version; bh=z7dErHKNz1kXk0WbYia6JgrHEdbkA7ClmZ6RunDjO2M=; b=EpbTkqSyabqfOCwLsd4z/kUh0yC+nT59MPRBBiR2z7kVguusLy8YGEi4 izyHyfiiaKOvK+Hs1Yx1U7PjQHaCA5/8f3+1i2bi/BeeyaoKlsRy5FulE bIwue49tGUOADatpS0zyti4jhfR2TtIGK+hEbE78850Gitu2iv3l392n/ 4=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: AhsFAO2Ir1GtJV2c/2dsb2JhbABagwkwvzF/FnSCIwEBAQQ6PwwEAgEIEQQBAQEKFBAyHQgBAQQBDQUIFodvvVqOegYrBwaCdGEDqH+DD4In
X-IronPort-AV: E=Sophos;i="4.87,809,1363132800"; d="scan'208";a="219244957"
Received: from rcdn-core-5.cisco.com ([173.37.93.156]) by rcdn-iport-5.cisco.com with ESMTP; 05 Jun 2013 18:57:06 +0000
Received: from xhc-rcd-x05.cisco.com (xhc-rcd-x05.cisco.com [173.37.183.79]) by rcdn-core-5.cisco.com (8.14.5/8.14.5) with ESMTP id r55Iv6s0024229 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Wed, 5 Jun 2013 18:57:06 GMT
Received: from xmb-rcd-x06.cisco.com ([169.254.6.154]) by xhc-rcd-x05.cisco.com ([173.37.183.79]) with mapi id 14.02.0318.004; Wed, 5 Jun 2013 13:57:05 -0500
From: "Rajiv Asati (rajiva)" <rajiva@cisco.com>
To: "Reinaldo Penno (repenno)" <repenno@cisco.com>, Michael Richardson <mcr+ietf@sandelman.ca>, "v6ops@ietf.org" <v6ops@ietf.org>
Thread-Topic: [BEHAVE] Home NAPT44 - How many ports?
Thread-Index: Ac5h7Gh9xwUId/SJTdSA920KKgIqlAAA9zuwAAkCoAAAB6fzgP//zuwA///5RqA=
Date: Wed, 05 Jun 2013 18:57:05 +0000
Message-ID: <B14A62A57AB87D45BB6DD7D9D2B78F0B116D3323@xmb-rcd-x06.cisco.com>
References: <20115.1370449415@sandelman.ca> <45A697A8FFD7CF48BCF2BE7E106F0604090A0A82@xmb-rcd-x04.cisco.com>
In-Reply-To: <45A697A8FFD7CF48BCF2BE7E106F0604090A0A82@xmb-rcd-x04.cisco.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [10.89.2.227]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Cc: "Softwires-wg list (softwires@ietf.org)" <softwires@ietf.org>, "Poscic, Kristian (Kristian)" <kristian.poscic@alcatel-lucent.com>, "behave@ietf.org" <behave@ietf.org>, "Erik Kline (ek@google.com)" <ek@google.com>
Subject: Re: [BEHAVE] 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: Wed, 05 Jun 2013 18:58:05 -0000

> >If one is doing CGN, wouldn't it be reasonable to point customers' at a
> >recursive DNS server with an interface inside the CGN?
> 
> Yes. That's what I suggest. But some people use, say, Google's
> DNS/OpenDns/etc and in some other cases the network is not setup
> correctly.

And in some cases, it is not possible depending on where the NAT function is placed and where the DNS server is placed. I recently ran into this in a large mobile network design. 

Nonetheless, it is desired, but it is not really a big deal, since UDP NAT usage tends to be a lot less than that TCP NAT usage (barring few exceptions).

> >This seems to also suggest that having a *caching* recursive DNS(SEC,
> >HOMENET+, mDNS+) server inside the customer router is also a big win.
> 
> Yes, it is.

Well, DNS resolver with or without proxy is a big win, I would say. 


Cheers,
Rajiv


> -----Original Message-----
> From: Reinaldo Penno (repenno)
> Sent: Wednesday, June 05, 2013 12:28 PM
> To: Michael Richardson; v6ops@ietf.org
> Cc: Poscic, Kristian (Kristian); Rajiv Asati (rajiva); Softwires-wg list
> (softwires@ietf.org); behave@ietf.org; Erik Kline (ek@google.com)
> Subject: Re: [BEHAVE] Home NAPT44 - How many ports?
> 
> 
> 
> On 6/5/13 1:23 PM, "Michael Richardson" <mcr+ietf@sandelman.ca> wrote:
> 
> >
> >>>>>> "repenno" == repenno  <Reinaldo> writes:
> >    repenno> On the other hand, as Rajiv captured,the number of
> >    repenno> UDP sessions can be much larger than the number of
> >    repenno> TCP. Because the way
> >    repenno> dynamic webpages are constructed today, there are
> sometimes
> >    repenno> literally 100s
> >    repenno> of DNS requests to download a single page.
> >
> >If one is doing CGN, wouldn't it be reasonable to point customers' at a
> >recursive DNS server with an interface inside the CGN?
> 
> Yes. That's what I suggest. But some people use, say, Google's
> DNS/OpenDns/etc and in some other cases the network is not setup
> correctly.
> 
> >
> >This seems to also suggest that having a *caching* recursive DNS(SEC,
> >HOMENET+, mDNS+) server inside the customer router is also a big win.
> 
> Yes, it is.
> 
> >
> >--
> >]               Never tell me the odds!                 | ipv6 mesh
> >networks [
> >]   Michael Richardson, Sandelman Software Works        | network
> >architect  [
> >]     mcr@sandelman.ca  http://www.sandelman.ca/        |   ruby on rails
> >   [
> >