Ron,
Also, this document needs to cite RFC4963 ("IPv4 Reassembly Errors at
High Data Rates") as it is a clear commentary on the fragile nature of IP
fragmentation.
Thanks - Fred
> -----Original Message-----
> From: Int-area [mailto:[email protected]] On Behalf Of Templin (US),
> Fred L
> Sent: Wednesday, November 21, 2018 8:47 AM
> To: Ron Bonica <[email protected]>; int-area <[email protected]>;
> [email protected]
> Subject: Re: [Int-area] draft-ietf-intarea-frag-fragile-03
>
> Hi Ron,
>
> There needs to be a new subsection in Section 6 on UDP applications that
> rely on IP fragmentation for greater performance. Here is proposed text:
>
> "Some UDP applications rely on IP fragmentation to achieve acceptable levels
> of performance. These applications use UDP datagram sizes that are larger than
> the path MTU so that more data can be conveyed between the application and
> the kernel in a single system call.
>
> Historically, NFS version 2 [RFC1094] set a UDP datagram size of 8KB which is
> greater than the path MTU of most paths, resulting in IP fragmentation.
> Currently, the Licklider Transmission Protocol [RFC5326] which is in current
> use on the International Space Station (ISS) uses UDP datagram sizes larger
> than the path MTU to achieve acceptable levels of performance even though
> this too invokes IP fragmentation. Also, the commonly-used iperf3 [IPERF3]
> performance testing utility by default sets an 8KB UDP datagram size even
> though IP fragmentation is invoked since the performance of smaller UDP
> datagrams is much lower.
>
> While it is natural to suggest that such applications should adjust their
> application layer framing to better match the path MTU, such does
> not always result in greater performance. For example, although the
> "sendmmsg()" system call was designed to present the kernel with
> multiple UDP datagrams in a single call, not all applications benefit
> from its use."
>
> Thanks - Fred
>
> > -----Original Message-----
> > From: Int-area [mailto:[email protected]] On Behalf Of Ron Bonica
> > Sent: Wednesday, November 21, 2018 6:32 AM
> > To: int-area <[email protected]>; [email protected]
> > Subject: [Int-area] draft-ietf-intarea-frag-fragile-03
> >
> > Chairs,
> >
> > I have posted a new version of draft-ietf-intarea-frag-fragile, working in
> > comments from Tom and Brian.
> >
> > If you see fit, please initiate a working group last call.
> >
> > Ron
> >
> > _______________________________________________
> > Int-area mailing list
> > [email protected]
> > https://www.ietf.org/mailman/listinfo/int-area
>
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