Ralph, What all information constitutes prefix information? If a node is DHCPv6 enabled in a RA-absent network, why isn't just the prefix length enough for the node to make an on-link determination with? In comparison, a node that is DHCPv6 enabled in a RA-present network uses prefix length and L bit together to make an on-link determination.
Thanks. Hemant -----Original Message----- From: Ralph Droms (rdroms) Sent: Friday, August 17, 2007 12:27 PM Subject: References: <[EMAIL PROTECTED]><7ECEF9368E169544B43882B [EMAIL PROTECTED]><8E296595B6471A4689555D [EMAIL PROTECTED]><8C324AEB-292B-42E5-A6B6-4 [EMAIL PROTECTED]><[EMAIL PROTECTED]><FDB [EMAIL PROTECTED]><[EMAIL PROTECTED] argle.gargle.HOWL><[EMAIL PROTECTED]><18115.3756.371573.1032 [EMAIL PROTECTED]><[EMAIL PROTECTED]><m1zm0reu44.wl%jin [EMAIL PROTECTED]><[EMAIL PROTECTED] rtp-20e.amer.cisco.com><[EMAIL PROTECTED]>< [EMAIL PROTECTED]><870 [EMAIL PROTECTED]><B00EDD615E3C5344B0FFCBA910C [EMAIL PROTECTED]><39C363776A4E8C4A94691D2BD9D1C9 [EMAIL PROTECTED]><B00EDD615E3C5344B0FFCBA910CF7E1 [EMAIL PROTECTED]> <18117.50055 [EMAIL PROTECTED]> <[EMAIL PROTECTED]> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <[EMAIL PROTECTED]> Cc: "James Carlson" <[EMAIL PROTECTED]>, [EMAIL PROTECTED], "Templin, Fred L" <[EMAIL PROTECTED]>, Iljitsch van Beijnum <[EMAIL PROTECTED]>, ipv6@ietf.org, JINMEI Tatuya / ???? <[EMAIL PROTECTED]> Content-Transfer-Encoding: 7bit From: Ralph Droms <[EMAIL PROTECTED]> Subject: Re: [dhcwg] Re: prefix length determination for DHCPv6 Date: Fri, 17 Aug 2007 12:27:46 -0400 To: "Hemant Singh (shemant)" <[EMAIL PROTECTED]> X-Mailer: Apple Mail (2.752.2) Return-Path: [EMAIL PROTECTED] X-OriginalArrivalTime: 17 Aug 2007 16:26:47.0602 (UTC) FILETIME=[685A1920:01C7E0EB] Send prefix information, not prefix lengths with assigned addresses. The little bit of savings in assuming the tie-in between assigned addresses and on-link prefixes is short-sighted. - Ralph On Aug 17, 2007, at Aug 17, 2007,12:23 PM, Hemant Singh (shemant) wrote: > Thanks, James. I agree with Fred then that a node can try DHCPv6. But > now how does the node get a prefix length? As you are saying, some > manual or static configuration can be used. I certainly don't like the > host to assume any prefix length in this scenario. Since I am not a > fan of any manual configuration, it does make sense, only for such a > case of absence of an RA, that DHCPv6 provides prefix length. Since > DHCPv6 doesn't know if the network's router will issue RA's or not, > then > DHCPv6 > has to provide prefix length all the time. > > Then I am for what Iljitsch is saying. If a host see a discrepancy in > prefix lengths from RA and DHCPv6, then host has to decide based on a > union of information. > > Hemant > > -----Original Message----- > From: James Carlson [mailto:[EMAIL PROTECTED] > Sent: Friday, August 17, 2007 11:49 AM > To: Hemant Singh (shemant) > Cc: Templin, Fred L; Iljitsch van Beijnum; [EMAIL PROTECTED]; > ipv6@ietf.org; JINMEI Tatuya / ???? > Subject: RE: [dhcwg] Re: prefix length determination for DHCPv6 > > Hemant Singh (shemant) writes: >> I have not found any information in the ND RFC's nor DHCPv6 RFC that >> say a node can initiate DHCPv6 if node doesn't receive any RA. I need >> to see explicit text in some document to accept what you said below. > > It does say this. See RFC 2462 section 4: > > The next phase of autoconfiguration involves obtaining a Router > Advertisement or determining that no routers are present. If > routers > are present, they will send Router Advertisements that specify what > sort of autoconfiguration a host should do. If no routers are > present, stateful autoconfiguration should be invoked. > > And then more forcefully in 5.5.2: > > 5.5.2. Absence of Router Advertisements > > If a link has no routers, a host MUST attempt to use stateful > autoconfiguration to obtain addresses and other configuration > information. An implementation MAY provide a way to disable the > invocation of stateful autoconfiguration in this case, but the > default SHOULD be enabled. From the perspective of > autoconfiguration, a link has no routers if no Router > Advertisements > are received after having sent a small number of Router > Solicitations > as described in [DISCOVERY]. > > It's certainly pointless unless you also have access to some static > prefix information, but it's what the documents say to do. > > -- > James Carlson, Solaris Networking > <[EMAIL PROTECTED]> > Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 > 2084 > MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 > 1677 > > _______________________________________________ > dhcwg mailing list > [EMAIL PROTECTED] > https://www1.ietf.org/mailman/listinfo/dhcwg -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
