Re: rfc4941bis: Change to Valid Lifetime of temporary addresses
Fernando Gont <fgont@si6networks.com> Tue, 11 February 2020 04:32 UTC
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Subject: Re: rfc4941bis: Change to Valid Lifetime of temporary addresses
To: Gyan Mishra <hayabusagsm@gmail.com>
Cc: "6man@ietf.org" <6man@ietf.org>
References: <9cb65947-f634-e250-bfdc-134cfa2c91e9@si6networks.com> <CABNhwV2CGDCMiKMguk1D-TAk2WDentAY6eo86scgejjkHMOJKQ@mail.gmail.com> <650ce9e8-1a61-df46-f9cc-174af99d7142@si6networks.com> <CABNhwV3sJ2U+En2f0bzG4+izQCuR8PxQt7s9kExSYZR5B6MAcg@mail.gmail.com> <2b9cec4a-bfd2-6d83-cd2a-820886cab20e@si6networks.com> <CABNhwV2SF-3HJtm2Bw=i-a7xAcS-=-dY=SOFMVtUs1wS05xtLA@mail.gmail.com>
From: Fernando Gont <fgont@si6networks.com>
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Date: Tue, 11 Feb 2020 01:31:51 -0300
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On 10/2/20 21:02, Gyan Mishra wrote: > > > On Mon, Feb 10, 2020 at 10:52 AM Fernando Gont <fgont@si6networks.com > <mailto:fgont@si6networks.com>> wrote: > > On 10/2/20 11:58, Gyan Mishra wrote: > > > > > > On Mon, Feb 10, 2020 at 4:14 AM Fernando Gont > <fgont@si6networks.com <mailto:fgont@si6networks.com> > > <mailto:fgont@si6networks.com <mailto:fgont@si6networks.com>>> wrote: > > > > On 10/2/20 01:44, Gyan Mishra wrote: > > [....] > > > Comments? Objections? > > > > > > Since we are proposing change of valid lifetime from 2 > to 1 why not > > > make the valid lifetime 1 day as well - same as the preferred. > > > > That's bad. That would mean that a connection that is started > T seconds > > before the address becomes invalid could only have a maximum > lifetime of > > T seconds. > > > > Put another way, in the worst case scenario where a new > connection is > > initiated with an address that is just about to become > unpreferred, the > > maximum lifetime of the connection is ValidLifetime - > PreferredLifetime. > > > > > > Walk me through it as far as end user impact when the address > > becomes unpreferred versus deprecated. > > > > So N = valid 1 day / preferred 1 day = 1 day > > > > As soon as the T time expires for preferred life it would become > > unpreferred but not deprecated. > > unpreferred == deprecated > > > > > What is the difference from end user standpoint and impact in > > connectivity with the address becoming unpreferred versus deprecated? > > Both are the same. > > > > > With existing connections would still be able to use the deprecated > > addresses at time T at the preferred expire time or would their > > connection be reset and they would have to re-establish on the new > > preferred address? > > > > If existing connections get reset with 2 day valid lifetime at > time T, > > then if seems no different then unpreferred which would get reset > as well. > > Please see RFC4861/RFC4862. > > > Found it > > So now I understand what is bad about valid = 1 day which I surmised but > was not sure. So the bad is the connection would reset immediately and > the address would become invalid once the valid expire time is reached > being the same as the preferred lifetime. Very bad for any IPv6 user. > > My concern is for long lived connections that may exist for enterprise > mission critical applications. So given the scenario of valid = 2 days > and preferred = 1 day as proposed - once the preferred lifetime expires > the address is deprecated- for en existing long lived connection would > continue to use the deprecated address until the valid lifetime is > reached at 2 days - at which time the address would become invalid. > > The current RFC 4291 valid =7 preferred=1 in that same scenario for a > long lived connection the flow could continue to use the deprecated > address until the valid lifetime expires which is 7 days at which time > it would become invalid and the connection would reset and have to > re-establish on the new preferred address. The major downside as we > have discussed is limiting the number of addresses on the host which a > valid lifetime change to 2 drastically drops the multiple prefixes from > 7 down to 2. From an operations perspective even though the 7 day valid > lifetime extends life of long lived but in those cases if we have flows > that last that long the operators can chose to disable the temporary > address as a workaround. Having less addresses is a better choice from > an operations perspective then being able maintain very long lived > connections. Not sure what you mean. Are you arguing that it's better to reduce the valid preferred/valid lifetime, or leave them as in RFC4941? Thanks, -- Fernando Gont SI6 Networks e-mail: fgont@si6networks.com PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
- rfc4941bis: Change to Valid Lifetime of temporary… Fernando Gont
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Gyan Mishra
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Fernando Gont
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Gyan Mishra
- rfc4941bis: Change to Valid Lifetime of temporary… Fernando Gont
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Fernando Gont
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Gyan Mishra
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Fernando Gont
- Re: rfc4941bis: Change to Valid Lifetime of tempo… David Farmer
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Lorenzo Colitti
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Fernando Gont
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Curtis, Bruce
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Fernando Gont
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Fernando Gont
- Re: rfc4941bis: Change to Valid Lifetime of tempo… Gyan Mishra