IETF Logo Mail Archive

Re: [dhcwg] What triggers a DHCP Information Request?

"Bernie Volz (volz)" <volz@cisco.com> Thu, 16 October 2014 15:42 UTC

Return-Path: <volz@cisco.com>
X-Original-To: dhcwg@ietfa.amsl.com
Delivered-To: dhcwg@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id C4C911A6EDA for <dhcwg@ietfa.amsl.com>; Thu, 16 Oct 2014 08:42:22 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -14.511
X-Spam-Level:
X-Spam-Status: No, score=-14.511 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001, T_RP_MATCHES_RCVD=-0.01, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id JiHO5K0GmMkv for <dhcwg@ietfa.amsl.com>; Thu, 16 Oct 2014 08:42:21 -0700 (PDT)
Received: from rcdn-iport-7.cisco.com (rcdn-iport-7.cisco.com [173.37.86.78]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 410831A3BA2 for <dhcwg@ietf.org>; Thu, 16 Oct 2014 08:42:21 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=1942; q=dns/txt; s=iport; t=1413474141; x=1414683741; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-transfer-encoding:mime-version; bh=0vH2WoudEC15LNaadu2DuG1KD6Jz8BziZH1i9LUz5Cg=; b=Ko520BkahQ0M1iwdr1yXcYii0BCEl/T+DGgHW+uB7F3xlftWuMEOKO1m sHEFQyKUdes0QGdwPD8Lhr+qO+4HIBJ5mNdH20MgIsUMjiuilRERz6s3D Krtj88LRW8m5npJuOiBeu1D56xXzq8TZfdqz335d3z3r0KVMsNUJEr/en I=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: AgkFANvmP1StJV2P/2dsb2JhbABbDoMAU1zMFAqHTQKBFhYBfYQCAQEBBAEBATc0CwwEAgEIDgMEAQEBChQJBycLFAkIAgQBDQUIiDYNylABAQEBAQEBAQEBAQEBAQEBAQEBAQETBJAcMQcGgyeBHgWRf5hSiSKDN0BsgUiBAgEBAQ
X-IronPort-AV: E=Sophos;i="5.04,732,1406592000"; d="scan'208";a="363795971"
Received: from rcdn-core-7.cisco.com ([173.37.93.143]) by rcdn-iport-7.cisco.com with ESMTP; 16 Oct 2014 15:42:20 +0000
Received: from xhc-rcd-x10.cisco.com (xhc-rcd-x10.cisco.com [173.37.183.84]) by rcdn-core-7.cisco.com (8.14.5/8.14.5) with ESMTP id s9GFgKYH019322 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Thu, 16 Oct 2014 15:42:20 GMT
Received: from xmb-rcd-x04.cisco.com ([169.254.8.78]) by xhc-rcd-x10.cisco.com ([173.37.183.84]) with mapi id 14.03.0195.001; Thu, 16 Oct 2014 10:42:20 -0500
From: "Bernie Volz (volz)" <volz@cisco.com>
To: Ted Lemon <mellon@fugue.com>, Timothy Winters <twinters@iol.unh.edu>
Thread-Topic: [dhcwg] What triggers a DHCP Information Request?
Thread-Index: AQHP6VWrWvKHW5FHAUC5IyhH1LfPV5wy2p6Q
Date: Thu, 16 Oct 2014 15:42:19 +0000
Message-ID: <489D13FBFA9B3E41812EA89F188F018E1B6D107D@xmb-rcd-x04.cisco.com>
References: <E37A320E-203D-408D-87E2-9A1D04A906AE@fugue.com> <E0CD6B78-0BE6-438D-8B88-3C933C5624CB@iol.unh.edu> <9E2CCAA8-3045-4AEC-85BB-37E9C20BB026@fugue.com>
In-Reply-To: <9E2CCAA8-3045-4AEC-85BB-37E9C20BB026@fugue.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [10.98.1.201]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Archived-At: http://mailarchive.ietf.org/arch/msg/dhcwg/MVArRJ_c6yrEBJiNiVGZyO-CuV0
Cc: dhcwg <dhcwg@ietf.org>
Subject: Re: [dhcwg] What triggers a DHCP Information Request?
X-BeenThere: dhcwg@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: <dhcwg.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dhcwg>, <mailto:dhcwg-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/dhcwg/>
List-Post: <mailto:dhcwg@ietf.org>
List-Help: <mailto:dhcwg-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dhcwg>, <mailto:dhcwg-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 16 Oct 2014 15:42:23 -0000

This might be a good issue to add in the 3315bis issues list - recommendations on when to initiate an Information-Request based on network changes.

I would guess that most clients trigger it when the refresh time (OPTION_INFORMATION_REFRESH_TIME option) expires or when some application request some data that hasn't been obtained (if the OS has this capability)?

Probably something (at least for the address selection policy table) that should have been covered in RFC 7078.

The text there is:

   The received information can be considered stale in several cases,
   e.g., when the interface goes down, the DHCP server does not respond
   for a certain amount of time, or the Information Refresh Time has
   expired.

Of course, the list is just 'e.g.' so could include more.

And, there might be some rate limiting that is applicable in case there is flapping of the RA prefix information.

- Bernie

-----Original Message-----
From: dhcwg [mailto:dhcwg-bounces@ietf.org] On Behalf Of Ted Lemon
Sent: Thursday, October 16, 2014 11:26 AM
To: Timothy Winters
Cc: dhcwg
Subject: Re: [dhcwg] What triggers a DHCP Information Request?

On Oct 16, 2014, at 10:01 AM, Timothy Winters <twinters@iol.unh.edu> wrote:
> 	 At the IOL I'm not aware of many DHCPv6 clients that trigger the DHCPv6 Information Request based on addresses being added.  I could see the case of when you lose all Global address (including ULA) a device might send one, but I would be surprised if they send when when new prefixes are found.   I can look closer into this to see what triggers it, give me a couple of days and I'll report back. 

That seems broken, because you probably want to refresh the source address selection policy table whenever you see a new prefix.

_______________________________________________
dhcwg mailing list
dhcwg@ietf.org
https://www.ietf.org/mailman/listinfo/dhcwg

v2.23.0 | Report a Bug | By Email