Tim and Gorry, thank you for this meeting report-out. I have a draft out right now that I think addresses most if not all of the points regarding larger packet sizes. The draft was aligned with intarea for a long time but was recently re-aligned with 6man and refactored to focus on IPv6. I did leave behind an intarea-aligned draft on IPv4 dependencies also though.
The draft is called: "IPv6 Parcels and Advanced Jumbos" and brings a comprehensive portfolio of techniques necessary to deal with these larger sizes in both the Internet and other generalized Internetworking scenarios. It is worth a look if you haven't already seen it, and worth another look if you already have. Thank you - Fred > -----Original Message----- > From: Int-area <int-area-boun...@ietf.org> On Behalf Of Tim Chown > Sent: Monday, December 18, 2023 8:15 AM > To: int-area@ietf.org > Cc: Gorry (erg) <go...@erg.abdn.ac.uk> > Subject: [Int-area] Jumbo frame side meeting at IETF118 - notes > > Hi, > > Apologies for the delay in posting these notes. Gorry and I held a side > meeting in Prague on the topic of (lack of) use of jumbo frames, and > what topics might lie within the IETF’s remit to help promote greater use. > > After talking to an AD it was suggested we raise the topic on the int-area > list to gauge interest, rather than set up a new list at this stage. > > So, all thoughts and comments welcome... > > -- > > Jumbo frame side meeting, IETF118, 2-3pm Thu 9 November > > Convened by Tim Chown (Jisc) and Gorry Fairhurst (Univ Aberdeen) > > The meeting had no set agenda. The aim was to gather those interested in more > widespread use of jumbo frames to gather and discuss > what actions might be taken in or by the IETF and its WGs towards that goal. > > Comments: > • There is no standard for Ethernet for frame sizes above 1500 bytes > • Would it be useful to work towards a “certified jumbo” interoperability > test? > • NICs at 1Gbit/s+ should all use phase-locked loop (PLL). > • What tools should we use to identify issues or errors in transmission > at various MTU sizes? > • Tim noted that Jisc’s 100G perfSONAR node at London showed no errors on > its 9000 MTU interface – stats can be seen under the > interface details section at https://ps-london-bw.perf.ja.net/toolkit/ > • We should consider the relevance of MTU in respective IETF areas – INT, > TSV and OPS > • Jen Linkova has talked about networks with multiple sizes of MTU > • There are providers who offer 9000 MTU networks, end-to-end, such as > Hurrican Electric > • Tim reported that many PBs of data are moved by the CERN experiments > and a proportion of that is using 9000 MTU. Single stream TCP > performance can be 2-3x better, depending on RTT and other factors. > • What issues might there be in specific technologies, e.g. ND, BGP, > ECMP, multipath TCP, …? > • There is a perception that IXPs find 9000 MTU problematic > • There are previous IETF I-Ds on MTU use, e.g. in IXPs – we should look > at old drafts or any RFCs > • There may be relevant presentations from *NOG and RIR member meetings > • Improvements to host stacks can make the performance gains of jumbo > frames less important, e.g. various offloading technologiesCan > we get current measurements and data, e.g., via MAPRG? > • We should look at hyperscalers; there is support there for 9000 MTU > • IPsec, and any encapsulation that benefits from avoiding fragmentation, > can work better with jumbo frames > • We could look a Globus transfer logs to detect MD5 errors for evidence > of issues in the application data not picked up at lower layers > • There are other non-Ethernet technologies used in DCs with large frames > • Does QUIC break offload due to its encryption? In practice QUIC uses a > Max Datagram Packet size less than 1500. Might larger MTUs > be useful for QUIC > • Post-quantum scenarios were mentioned. > • What about MTU discovery? There is anecdotal evidence of issues; Tim > has seen this at a UK university where ICMPv6 PTB was being > dropped. > • PLPMTUD is specified by QUIC; useful when there’s no path back to a > sender for receipt of an ICMP PTB message. > > Agreed actions: > • Tim will ask Eric Vyncke (INT area AD) for support to create a > “jumbo-discuss” IETF mail list > • We will seek to collectively document the status of jumbo frames, > focusing on what works (success stories), opportunities, gaps > (potential work items in the IETF and elsewhere) and other open issues. > • Tim will ask Eric Vyncke for a side meeting at a future IETF. > • We will seek to present relevant parts of the above documented status > in the INT, TSV and OPS area open meetings at the next IETF > meeting. > • Tim will email the 118attendees list with the meeting notes > > — > > Tim > _______________________________________________ > Int-area mailing list > Int-area@ietf.org > https://www.ietf.org/mailman/listinfo/int-area _______________________________________________ Int-area mailing list Int-area@ietf.org https://www.ietf.org/mailman/listinfo/int-area
