Date: Thu, 07 Dec 2006 07:12:09 -0500 From: Randall Stewart <rrs@cisco.com> To: Ivo Vachkov <ivo.vachkov@gmail.com> Cc: Michael Tuexen <Michael.Tuexen@lurchi.franken.de>, freebsd-net@freebsd.org Subject: Re: Urel, a TCP option for Unreliable Streaming. Need your help. Message-ID: <45780519.6050207@cisco.com> In-Reply-To: <f85d6aa70612070154t112799dewcb9d090164531da2@mail.gmail.com> References: <161d69110612060709n3bf99bd4y47d94b021b8f1d02@mail.gmail.com> <m21wncv66z.wl%gnn@neville-neil.com> <4577D858.4010300@freebsd.org> <2786D1DE-E8FA-490C-AFF7-E458E262AEF7@lurchi.franken.de> <f85d6aa70612070154t112799dewcb9d090164531da2@mail.gmail.com>
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Ivo Vachkov wrote: > On 12/7/06, Michael Tuexen <Michael.Tuexen@lurchi.franken.de> wrote: > >> >> Hi Andre, >> >> see my comments in-line. >> >> Best regards >> Michael >> >> >> SCTP has a extension called PR-SCTP, which is implemented in BSD >> and can be used to limit the number of retransmissions of a >> DATA chunk to 0. The service you mention above is therefore available >> in SCTP. > > > > > There is only one problem with that - you need to do a major rewrite of > your > current software to use SCTP No, I disagree here.. we designed the API of SCTP to literally be completely compatible with TCP.. You do sd = socket(AF_INET, SOCK_STREAM, 0); change this to sd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP); and you now have SCTP .. if you use a socket option or two (no delay for example) you will have to change this to the SCTP equivlant.. which are conviently named the smae with SCTP_ at the prefix... There is also a shim layer that makes it so you can do both TCP and SCTP (trying SCTP first).. but thats not ready yet.. ;-) and hope that all OSs it's supposed to run > on/with have SCTP support (and it's enabled). Ahh.. well there is that.. all O/S's (current ones at least) support SCTP with the exception of WinDoz.. You can add a package to WinDoz to make SCTP run on it.. but no one likes to do that :-) And besides.. if you are doing partial reliable TCP do you really think you can do it without both ends supporting it? The same problem would exist here.. R > -- Randall Stewart NSSTG - Cisco Systems Inc. 803-345-0369 <or> 803-317-4952 (cell)
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