> On Nov 1, 2019, at 7:32 PM, Manoj Nayak <[email protected]> wrote: > > Hello Joe, > > I was reading the following comment. Even when router takes care of > generating equal sized fragments, the last fragment is > most likely to be less than rest of the fragments.
See RFC 1812. Not all fragmentation algs have unequal sizes or the smallest chunk last. There are no requirements on this. > > "why would this approach find the largest fragment through a system? > rfc1812 talks about various strategies, one of which is ?equal sized?, which > might never find the max the way you propose" > > > Regards > Manoj Nayak > > -----Original Message----- > From: Joe Touch <[email protected]> > Sent: Wednesday, October 30, 2019 12:44 AM > To: Ron Bonica <[email protected]> > Cc: [email protected] > Subject: Re: [Int-area] New Version Notification for > draft-bonica-intarea-lossless-pmtud-00.txt > > Hi, Ron, > > A few things come to mind. The first one, IMO, renders the rest somewhat > less important. > > Joe > > ------------- > > - this approach applies only to IPv4; not sure it?s worth trying to > optimize for only that case > (it requires on-path fragmentation permitted) > > - this approach relies on ICMPs, so it?s as robust (or, more to the point, > not) as PMTUD > if ICMPs can find the reverse path from the dest, why wouldn?t the > routers? > i.e., isn?t the problem with ICMPs not just routers not sending them > but firewalls BLOCKING them? > (i.e., if ICMPs would work here, PMTU would have worked, rendering > this unnecessary) > > - why does this doc assume the max ICMP is 576? > we?re still talking IPv4 here; it?s still 68 (that?s why only 64 bits > of the orig payload are guaranteed) > (yes, your note in the end of sec 1 is relevant, but given v4-in-v4 > tunneling, it?s possible that paths might be smaller than the 576 assumption) > > - why would this approach find the largest fragment through a system? > rfc1812 talks about various strategies, one of which is ?equal sized?, > which might never find the max the way you propose > > >> On Oct 29, 2019, at 9:53 AM, Ron Bonica >> <[email protected]> wrote: >> >> Folks, >> >> Please review and comment. >> >> Ron >> >> >> >> Juniper Business Use Only >> >> -----Original Message----- >> From: [email protected] <[email protected]> >> Sent: Tuesday, October 29, 2019 11:48 AM >> To: Ron Bonica <[email protected]>; Hakan Alpan <[email protected]>; Radon >> Rosborough <[email protected]>; Bradely Newton <[email protected]>; Miles >> President <[email protected]>; Manoj Nayak <[email protected]> >> Subject: New Version Notification for >> draft-bonica-intarea-lossless-pmtud-00.txt >> >> >> A new version of I-D, draft-bonica-intarea-lossless-pmtud-00.txt >> has been successfully submitted by Ron Bonica and posted to the IETF >> repository. >> >> Name: draft-bonica-intarea-lossless-pmtud >> Revision: 00 >> Title: Lossless Path MTU Discovery (PMTUD) >> Document date: 2019-10-29 >> Group: Individual Submission >> Pages: 8 >> URL: >> https://urldefense.com/v3/__https://tools.ietf.org/html/draft-bonica-intarea-lossless-pmtud-00__;!8WoA6RjC81c!SaG54qXv3mOmFFinOp93hDtn-j4u5ZzUbomMfaHAujluBDj7pJq_RtQMALmTf6K4$ >> >> >> >> >> Abstract: >> This document describes alternative IPv4 PMTUD procedures that do not >> prevent IP fragmentation and do no rely on the network's ability to >> deliver ICMP Destination Unreachable messages to the source node. >> This document also defines a new ICMP message. IPv4 nodes emit this >> new message when they reassemble a fragmented packet. >> >> >> >> >> Please note that it may take a couple of minutes from the time of submission >> until the htmlized version and diff are available at tools.ietf.org. >> >> The IETF Secretariat >> _______________________________________________ >> Int-area mailing list >> [email protected] >> https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/int-area__;!8WoA6RjC81c!SaG54qXv3mOmFFinOp93hDtn-j4u5ZzUbomMfaHAujluBDj7pJq_RtQMAGjVmADJ$ >> > > ------------------------------ > > Message: 2 > Date: Thu, 31 Oct 2019 19:16:38 +0000 > From: Ron Bonica <[email protected]> > To: "[email protected]" <[email protected]> > Subject: [Int-area] FW: New Version Notification for > draft-bonica-intarea-lossless-pmtud-01.txt > Message-ID: > > <bn7pr05mb5699a257d6a46b016fbcd539ae...@bn7pr05mb5699.namprd05.prod.outlook.com> > > Content-Type: text/plain; charset="utf-8" > > > Updated draft > > > Juniper Business Use Only > > -----Original Message----- > From: [email protected] <[email protected]> > Sent: Thursday, October 31, 2019 3:15 PM > To: Ron Bonica <[email protected]>; Hakan Alpan <[email protected]>; Radon > Rosborough <[email protected]>; Bradely Newton <[email protected]>; Bradley > Newton <[email protected]>; Miles President <[email protected]>; Manoj Nayak > <[email protected]> > Subject: New Version Notification for > draft-bonica-intarea-lossless-pmtud-01.txt > > > A new version of I-D, draft-bonica-intarea-lossless-pmtud-01.txt > has been successfully submitted by Ron Bonica and posted to the IETF > repository. > > Name: draft-bonica-intarea-lossless-pmtud > Revision: 01 > Title: Lossless Path MTU Discovery (PMTUD) > Document date: 2019-10-31 > Group: Individual Submission > Pages: 7 > URL > https://urldefense.com/v3/__https://tools.ietf.org/html/draft-bonica-intarea-lossless-pmtud-01__;!8WoA6RjC81c!XLNEZ-1XcW1SCcQkdY1e72UP_43UD2slIH4JB_BJ-gO_XISUMzEDSldcRkqU5JMOvqw$ > > Abstract: > This document describes alternative IPv4 PMTUD procedures that do not > prevent IP fragmentation and do no rely on the network's ability to > deliver ICMP Destination Unreachable messages to the source node. > This document also defines a new ICMP message. IPv4 nodes emit this > new message when they reassemble a fragmented packet. > > > > > Please note that it may take a couple of minutes from the time of > submission until the htmlized version and diff are available at > tools.ietf.org. > > The IETF Secretariat > > ------------------------------ > > Message: 3 > Date: Thu, 31 Oct 2019 16:51:10 -0700 > From: Bob Hinden <[email protected]> > To: Ron Bonica <[email protected]> > Cc: Bob Hinden <[email protected]>, "[email protected]" > <[email protected]> > Subject: Re: [Int-area] New Version Notification for > draft-bonica-intarea-lossless-pmtud-01.txt > Message-ID: <[email protected]> > Content-Type: text/plain; charset="utf-8" > > Ron, > > A few comments on your draft. > > Naming the draft "Lossless Path MTU Discovery (PMTUD)? seems to be very > aspirational, and is an oxymoron. ICMP message can be rate limited and > dropped in the network. Hardly ?lossless?. A different title might be > better. > > I do like the idea of the destination sending feedback, we have worked on > some other drafts with that property. > > The document says: > > This document describes alternative PMTUD procedures that do no rely > on the network's ability to deliver ICMP Destination Unreachable > messages to the source node. In these procedures, the source node > produces an initial PMTU estimate. This initial estimate is equal to > the MTU of the first link along the path to the destination node. It > can be greater than the actual PMTU. > > This is not really correct, your are still dependent on the networks > ability to deliver ICMP messages to the source node. Just not ICMP > Destination Unreachable messages. A new ICMP message isn?t going to be > better, perhaps worse. > > I didn?t understand the purpose of the Code field, that can indicate > reassembly error. What is the purpose of this? This seems to be in > conflict with this message that is sent when the destination node > successfully reassemblies a set of fragments. With the code indicating > reassembly error, it is saying that the fragments were not reassembled. > > It may be folly to try to modify IPv4 implementations at this point. I > have no objections if you wish to try pushing this big rock up hill, but I > doubt you will be successful. > > I see you have several co-authors from Harvey Mudd College. > > Bob > > >> On Oct 31, 2019, at 12:16 PM, Ron Bonica >> <[email protected]> wrote: >> >> >> Updated draft >> >> >> Juniper Business Use Only >> >> -----Original Message----- >> From: [email protected] <[email protected]> >> Sent: Thursday, October 31, 2019 3:15 PM >> To: Ron Bonica <[email protected]>; Hakan Alpan <[email protected]>; Radon >> Rosborough <[email protected]>; Bradely Newton <[email protected]>; Bradley >> Newton <[email protected]>; Miles President <[email protected]>; Manoj Nayak >> <[email protected]> >> Subject: New Version Notification for >> draft-bonica-intarea-lossless-pmtud-01.txt >> >> >> A new version of I-D, draft-bonica-intarea-lossless-pmtud-01.txt >> has been successfully submitted by Ron Bonica and posted to the IETF >> repository. >> >> Name: draft-bonica-intarea-lossless-pmtud >> Revision: 01 >> Title: Lossless Path MTU Discovery (PMTUD) >> Document date: 2019-10-31 >> Group: Individual Submission >> Pages: 7 >> URL >> https://urldefense.com/v3/__https://tools.ietf.org/html/draft-bonica-intarea-lossless-pmtud-01__;!8WoA6RjC81c!XLNEZ-1XcW1SCcQkdY1e72UP_43UD2slIH4JB_BJ-gO_XISUMzEDSldcRkqU5JMOvqw$ >> >> Abstract: >> This document describes alternative IPv4 PMTUD procedures that do not >> prevent IP fragmentation and do no rely on the network's ability to >> deliver ICMP Destination Unreachable messages to the source node. >> This document also defines a new ICMP message. IPv4 nodes emit this >> new message when they reassemble a fragmented packet. >> >> >> >> >> Please note that it may take a couple of minutes from the time of submission >> until the htmlized version and diff are available at tools.ietf.org. >> >> The IETF Secretariat >> _______________________________________________ >> Int-area mailing list >> [email protected] >> https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/int-area__;!8WoA6RjC81c!XLNEZ-1XcW1SCcQkdY1e72UP_43UD2slIH4JB_BJ-gO_XISUMzEDSldcRkqUNjQlVhU$ >> > > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: signature.asc > Type: application/pgp-signature > Size: 488 bytes > Desc: Message signed with OpenPGP > URL: > <https://urldefense.com/v3/__https://mailarchive.ietf.org/arch/browse/int-area/attachments/20191031/999da00d/attachment.asc__;!8WoA6RjC81c!XLNEZ-1XcW1SCcQkdY1e72UP_43UD2slIH4JB_BJ-gO_XISUMzEDSldcRkqUrBUvJx8$ > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Int-area mailing list > [email protected] > > https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/int-area__;!8WoA6RjC81c!XLNEZ-1XcW1SCcQkdY1e72UP_43UD2slIH4JB_BJ-gO_XISUMzEDSldcRkqUNjQlVhU$ > > > > ------------------------------ > > End of Int-area Digest, Vol 170, Issue 14 > ***************************************** > > _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
