From: Michael Tuexen <firstname.lastname@example.org> To: Xin Long <email@example.com> Cc: "linux-sctp @ vger . kernel . org" <firstname.lastname@example.org>, Marcelo Ricardo Leitner <email@example.com> Subject: Re: add SPP_PLPMTUD_ENABLE/DISABLE flag for spp_flags Date: Tue, 18 May 2021 21:19:21 +0200 [thread overview] Message-ID: <DE8A113C-DF80-412E-A5C1-C0731E1757E2@freebsd.org> (raw) In-Reply-To: <CADvbK_eKp+1OUT1+DLdv5w5_Azsh7W3F46p=3hCoiP8c13bEFg@mail.gmail.com> > On 18. May 2021, at 20:33, Xin Long <firstname.lastname@example.org> wrote: > > On Tue, May 18, 2021 at 1:38 PM Michael Tuexen <email@example.com> wrote: >> >>> On 18. May 2021, at 18:43, Xin Long <firstname.lastname@example.org> wrote: >>> >>> Hi, Michael, >>> >>> We're implementing RFC8899 (PLPMTUD) on Linux SCTP recently, >>> and to make this be controlled by setsockopt with >>> SCTP_PEER_ADDR_PARAMS, as in >>> >>> https://datatracker.ietf.org/doc/html/rfc6458#section-8.1.12: >>> >>> we need another two flags to add for spp_flags: >>> >>> SPP_PLPMTUD_ENABLE >>> SPP_PLPMTUD_DISABLE >>> >>> Do you think it makes sense? if yes, does the RFC6458 need to update? >>> if not, do you have a better suggestion for it? >> It is great new that you want to implement RFC 8899. I plan to do the >> same for the FreeBSD stack. >> >> In my view, RFC 8899 is the right way to implement PMTU discovery. >> So I will just use the SPP_PMTUD_ENABLE and SPP_PMTUD_DISABLE. I don't >> think that the user needs to control which method is used. >> I you want to support multiple versions, I would make that >> controllable via a sysctl variable. But I think for FreeBSD, support >> for RFC 8899 will be the only way of doing PMTU discovery. There >> might be multiple choices for details like how to do the searching, >> how long to wait for some events. These will be controllable via >> sysctl. >> >> So in my view, there is no need to extend the socket API. What do you think? > OK, that makes sense to me. > > Another thing I want to know your opinion on is: do you think the HB > should be created > separately for PLPMTUD probe, instead of reusing the old HB that > checks the link connectivity? Yes. I think testing for connectivity is conceptually different from testing a particular PMTU. When testing for PMTU, I think about sending probe packets. Not that they consist of a HB chunk bundled with a PAD chunk. > As the HB for PLPMTUD probe might get lost, which we don't want to > affect the link's > connectivity. Yes, I agree completely. Best regards Michael > >> >> Best regards >> Michael >>> >>> Thanks. >>
next prev parent reply other threads:[~2021-05-18 19:19 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-18 16:43 Xin Long 2021-05-18 17:38 ` Michael Tuexen 2021-05-18 18:33 ` Xin Long 2021-05-18 19:19 ` Michael Tuexen [this message] 2021-05-19 22:24 ` mleitner 2021-05-20 2:05 ` Xin Long 2021-05-20 7:06 ` tuexen 2021-05-20 15:13 ` Xin Long 2021-05-19 16:18 ` Xin Long 2021-05-19 18:15 ` Michael Tuexen 2021-05-19 18:44 ` Xin Long 2021-05-19 22:44 ` mleitner 2021-05-19 23:16 ` Michael Tuexen 2021-05-20 0:45 ` Marcelo Ricardo Leitner 2021-05-20 6:59 ` tuexen 2021-05-20 19:27 ` Marcelo Ricardo Leitner 2021-05-19 23:10 ` Michael Tuexen
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