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.
"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
