Re: rfc4941bis: Invalid addresses used by ongoing sessions

On Mon, Feb 10, 2020 at 11:12 AM Fernando Gont <fgont@si6networks.com>
wrote:

> Folks,
>
> As currently specified, temporary addresses are removed when they become
> invalid (i.e., the Valid Lifetime expires).
>
> Section 6 ("6.  Future Work") of the draft
> (https://tools.ietf.org/id/draft-ietf-6man-rfc4941bis-06.txt) still
> keeps the following text from RFC4941.
>
> 6.  Future Work
>
>    An implementation might want to keep track of which addresses are
>    being used by upper layers so as to be able to remove a deprecated
>    temporary address from internal data structures once no upper layer
>    protocols are using it (but not before).  This is in contrast to
>    current approaches where addresses are removed from an interface when
>    they become invalid [RFC4862], independent of whether or not upper
>    layer protocols are still using them.  For TCP connections, such
>    information is available in control blocks.  For UDP-based
>    applications, it may be the case that only the applications have
>    knowledge about what addresses are actually in use.  Consequently, an
>    implementation generally will need to use heuristics in deciding when
>    an address is no longer in use.
>
>
> I wonder if this text should be:
>
> 1) moved more into the body of the document and made a "MAY" (which for
> TCP is very straightforward),
>
> 2) Be left "as is", or,
>
> 3) Removed from the document
>
>
> The implications of #1 above is that it can't prevent long-lived
> connections that employ temporary addresses from being torn down, at the
> expense of possibly increasing the number of concurrent IPv6 addresses.

  Gyan> So for TCP apps it maybe easier to track via active TCB blocks so
those long lived connections could be tracked.  So those long lived TCP
connections would not be impacted and torn down.  Other apps using UDP may
not be as easily tracked and so maybe using the deprecated address, however
due to difficulty of tracking maybe torn down as a side effect of option
#1.

>
>
> Thoughts?
>
> Thanks!
>
> Cheers,
> --
> Fernando Gont
> SI6 Networks
> e-mail: fgont@si6networks.com
> PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
>
>
>
>
> --------------------------------------------------------------------
> IETF IPv6 working group mailing list
> ipv6@ietf.org
> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
> --------------------------------------------------------------------
>
-- 

Gyan  Mishra

Network Engineering & Technology

Verizon

Silver Spring, MD 20904

Phone: 301 502-1347

Email: gyan.s.mishra@verizon.com