[Int-area] Re: IP Parcels and Advanced Jumbos (AJs)

Hi Tom,

I would like to gently suggest a new terminology. Rather than calling them "the multi-segment buffers managed by GSO and GRO", can we begin calling them "parcel buffers" or simply "parcels"? Not suggesting this in a self-serving manner - I just think it is a more concise yet more descriptive terminology.

Thank you - Fred

> -----Original Message-----
> From: Tom Herbert <[email protected]>
> Sent: Thursday, September 26, 2024 10:15 AM
> To: Tim Chown <[email protected]>
> Cc: Paul Vixie <[email protected]>; Templin (US), Fred L <[email protected]>; Internet Area <[email protected]>; IPv6 List
> <[email protected]>
> Subject: Re: [Int-area] Re: IP Parcels and Advanced Jumbos (AJs)
> 
> On Thu, Sep 26, 2024 at 9:03 AM Tim Chown
> <[email protected]> wrote:
> >
> > Hi,
> >
> >
> >
> > From: Paul Vixie <[email protected]>
> > Date: Tuesday, 24 September 2024 at 20:59
> > To: Templin (US), Fred L <[email protected]>, Internet Area <[email protected]>, IPv6 List <[email protected]>
> > Subject: [Int-area] Re: IP Parcels and Advanced Jumbos (AJs)
> >
> > Something like this is long needed and will become badly needed. Every 10X of speed increase since 10mbit/sec has gone straight to PPS,
> whereas the speed increase from 3mbit/sec to 10mbit/sec was shared between PPS and MTU.
> >
> >
> >
> > If every 10X has been shared between PPS and MTU, say sqrt(10) for each, our MTU would be well over 64K by now and our PPS wouldn't
> require dedicated NPU hardware to source, sink, and ferry those packets at link saturation levels.
> >
> >
> >
> > Every attempt at PMTUD so far has failed but that's not an excuse to stop trying.
> >
> >
> >
> > I think that depends on the deployment scenario and environment.  In R&E networking the adoption of 9000 MTU for large scale wide
> area data transfers has grown, in particular by dozens of sites worldwide that take part in the CERN experiments. CERN did a site survey
> recently, for which I could dig out the results.
> >
> >
> >
> > The sites running 9000 MTU are interoperating with the sites still at 1500, which is an indication that PMTUD is working well enough. The
> large majority of CERN traffic is IPv6, so for that there’s no fragmentation on path.
> 
> Tim,
> 
> That's also happening in some datacenters. I believe Google is using a
> 9K MTU internally as it makes zero copy on hosts feasible (two 4K
> pages per packet). Interestingly, there's also increasing use of
> RFC2675 jumbograms, they're not sent on the wire but used internally
> for GSO and GRO for greater than 64K packets.
> 
> Tom
> >
> >
> >
> > The use case is somewhat constrained in that it’s only the parts of the campus with the storage, the campus paths to the edge, and the
> intervening R&E backbones that need to be configured. But with correct ICMPv6 filtering, it seems robust.
> >
> >
> >
> > Best wishes,
> >
> > Tim
> >
> >
> >
> >
> >
> > Thanks for driving this Fred.
> >
> >
> >
> > p vixie
> >
> >
> >
> > On Sep 24, 2024 14:39, "Templin (US), Fred L" <[email protected]> wrote:
> >
> > It has been a while since I have posted about this, and there are some updates to highlight.
> >
> > See below for the IPv6 and IPv4 versions of “IP Parcels and Advanced Jumbos (AJs)”:
> >
> >
> >
> > https://datatracker.ietf.org/doc/draft-templin-6man-parcels2/
> >
> > https://datatracker.ietf.org/doc/draft-templin-intarea-parcels2/
> >
> >
> >
> > The documents acknowledge that parcels are analogous to Generic Segment/Receive Offload
> >
> > (GSO/GRO) but taken to the ultimate aspiration of encapsulating multi-segment buffers in
> >
> > {TCP/UDP}/IP headers for transmission over parcel-capable network paths. They further give
> >
> > a name to the multi-segment buffers used by GSO/GRO, suggesting that they be called
> >
> > “parcel buffers” or simply “parcels”.
> >
> >
> >
> > AJs are simply single-segment parcels that can range in size from very small to very large.
> >
> > They differ from ordinary jumbograms in several important ways, most notably in terms
> >
> > of integrity verification and error correction. They also suggest a new link service model
> >
> > that defers integrity checks to the end systems where bad data can be discarded while
> >
> > good data can be accepted as an end-to-end function, reducing retransmissions.
> >
> >
> >
> > Together, these documents cover all possible packet sizes and configurations that may
> >
> > be necessary both in the near term and for the foreseeable future for Internetworking
> >
> > performance maximization . Comments on the list(s) are welcome.
> >
> >
> >
> > Fred Templin
> >
> > _______________________________________________
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