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

Forgot to also mention the ATM days of the 1990s, which I was not directly involved in but
had colleagues at DEC who were. AAL5 set an MTU of 9180 for IP over ATM.

> -----Original Message-----
> From: Templin (US), Fred L <[email protected]>
> Sent: Friday, September 27, 2024 8:31 AM
> To: Brian E Carpenter <[email protected]>; Tom Herbert <[email protected]>; Tim Chown <[email protected]>
> Cc: Internet Area <[email protected]>; IPv6 List <[email protected]>
> Subject: [Int-area] Re: IP Parcels and Advanced Jumbos (AJs)
> 
> Rolling back a bit to an earlier message:
> 
> > RFC2675 jumbograms are single datagrams. They were originally intended for use over HIPPI, i.e.
> > internally to data centres as they existed 25 years ago
> 
> Yes, I worked in one of those data centers (NASA Ames Research) 1996/1997 timeframe so actually a
> bit more than 25 years ago. Before that, I was involved with the DEC FDDI program in the late 1980s.
> So, I am not new to the subject of larger packet sizes, and the subject of larger packet sizes is not
> new to the industry in general.
> 
> Thank you - Fred
> 
> > -----Original Message-----
> > From: Brian E Carpenter <[email protected]>
> > Sent: Thursday, September 26, 2024 1:22 PM
> > To: Templin (US), Fred L <[email protected]>; Tom Herbert <[email protected]>; Tim Chown <[email protected]>
> > Cc: Internet Area <[email protected]>; IPv6 List <[email protected]>
> > Subject: [EXTERNAL] Re: [Int-area] Re: IP Parcels and Advanced Jumbos (AJs)
> >
> > EXT email: be mindful of links/attachments.
> >
> >
> >
> > On 27-Sep-24 05:56, Templin (US), Fred L wrote:
> > > 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.
> >
> > But that isn't the same thing. RFC2675 jumbograms are single datagrams. They were originally intended for use over HIPPI, i.e. internally
> to
> > data centres as they existed 25 years ago, so the usage that Tom reported seems close to what they were designed for.
> >
> > Tom, is there a full description of this usage?
> >
> > Regards
> >     Brian
> >
> > >
> > > 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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> > >
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