Hi Mark,
On Tue, 25 Jun 2024, Mark Andrews wrote:
On 25 Jun 2024, at 10:32, Scott Johnson <sc...@spacelypackets.com> wrote:
Hi Mark,
On Tue, 25 Jun 2024, Mark Andrews wrote:
An obvious correction “LTP--v6” -> “LTP-v6”
Aha! Good eye.
For IPN why isn’t the wire format two network 64 bit integers? That is 16 bytes.
Also 2^64-1 is 20 characters so 2 64-bit numbers separated by “." is 41
characters. It’s not clear where then 21 comes from.
EID is the basic unit of IPN naming, which is indeed two 64 bit integers separated by a
".". We are seeking to represent only the node-nbr component of an EID, as the
service-nbr component is loosely analagous to a UDP or TCP port, for which there is one
publicly defined service in the registry, and a collection of space agencies who lay
claim to another chunk of them:
https://www.iana.org/assignments/bundle/bundle.xhtml#cbhe-service-numbers
As such, there is no gain in including the second 64-bit integer, representing
service-nbr in the DNS records, and indeed, a loss of utility on the
application level.
The node-nbr component is presently, under RFC7116, a 64 bit unsigned integer.
There is a draft from the DTN WG currently making it's way through the IESG
which will amend the IPN naming scheme. Perhaps I should add it to normative
references?
https://datatracker.ietf.org/doc/draft-ietf-dtn-ipn-update/
In effect it splits the node-nbr component into two-32 bit integers; Allocator Identifier and Node Number in
the "Three-Element Scheme-Specific Encoding" of Section 6.1.2 over the above. Section 6.1.1
describes the "Two-Element Scheme-Specific Encoding" method which retains the use of a single
64-bit integer. Thus, a single 64 bit integer (20 characters) or two 32-bit integers (10 characters each)
delimited by a "."
makes 21 characters maximum. This preserves forwards compatibility with the
proposed amended scheme, and does no harm if the scheme fails to achieve
standardization.
Or just 8 bytes on the wire with both possible input formats described.
Machines using the records will just be converting ASCII values to a 64
bit integer. We may as well transmit it as that. Input validation will
need to do the conversion anyway to ensure both fields will fit into 32
bits in the “.” separated case and 64 bits in the single value case.
Length along is not sufficient to prevent undetected overflows. The
only thing you need to determine is which format is the initial
canonical presentation format. That can be changed with a later update
if needed.
I am tagging in Scott Burleigh, co-author of RFC9171 on this point for
clarification.
Section 4.2.5.1.2 of same indicates:
"Encoding considerations:
For transmission as a BP endpoint ID, the scheme-specific part of a
URI of the ipn scheme SHALL be represented as a CBOR array comprising two
items. The first item of this array SHALL be the EID's node number (a
number that identifies the node) represented as a CBOR unsigned integer.
The second item of this array SHALL be the EID's service number (a number
that identifies some application service) represented as a CBOR unsigned
integer. For all other purposes, URIs of the ipn scheme are encoded
exclusively in US-ASCII characters."
Having already established that we are transmitting the node-nbr component
only, and not a full EID, I am not sure we are restricted to using only
US-ASCII. ScottB, your opinion? CBOR might also be an option, but that
would place a higher burden upon implementers, I think. Integer notation
for wire format is fine by me.
Limit CLA characters to Letter Digit Hyphen rather than the full ASCII range.
It is possible for a node to support multiple CLAs on the same IP
address and node number. Will this change allow multiple, comma
delimited values to be expressed in the CLA record? If so, can you
point me to an example so I can get the verbiage of the draft right?
If not, what do you recommend (in addition to my defining that in the
draft)? I like the idea of limiting the usable characters.
Personally I would just use a TXT record wire format with the additional
constraint that the values are restricted to Letter, Digits and interior
Hyphens. The input format matches the TXT record with the above
character value constraints. The canonical presentation form is space
separated, unquoted, unescaped ASCII. This allow for long records to be
split over multiple lines. Descriptive comments in the zone file.
This take one extra octet over using comma separated values.
Sold to the man from ISC :) This part works great; thank you! Updated
draft pushed to datatracker at
https://datatracker.ietf.org/doc/draft-johnson-dns-ipn-cla/
Thanks,
Scott
e.g.
example inputs
@ CLA ( TCP-V4 ; TCP over IPv4
TCP-V6 ) ; TCP over IPv6
@ CLA “TCP-V4” TCP-V6
Wire
06 ’T’ ‘C’ ‘P’ ‘-‘ ‘V’ ‘4’ 06 ’T’ ‘C’ ‘P’ ‘-‘ ‘V’ ‘6’
Canonical presentation
@ CLA TCP-V4 TCP-V6
Thanks,
Scott
Mark
On 25 Jun 2024, at 08:19, Scott Johnson <sc...@spacelypackets.com> wrote:
Hi All,
After reading the recent discussion about WALLET, I am hesitant to jump into
the fray here, but this plainly is the correct group to help me get my logic
and syntax right, so here goes:
I submitted requests to IANA for IPN and CLA RRTYPEs, these representing the
missing datasets necessary to make a BP overlay network connection from data
found by DNS queries.
For those not familiar, BP is a store and forward mechanism generally used in
high latency situations where there does not exist constant end-to-end
connectivity. It was designed for deep space networking, however has network
segments and application uses which overlay the terrestrial Internet. There
will arise similar use cases on the Moon (in the reasonably near future) and
Mars whereby low latency, constant connectivity exists, thereby making use of
DNS in these situations viable.
My Expert Reviewer asked for an i-d, to clarify the requests, and that said i-d
be sent to this list for review.
Please find the approptiate draft here:
https://datatracker.ietf.org/doc/draft-johnson-dns-ipn-cla/
Relevant IANA requests:
https://tools.iana.org/public-view/viewticket/1364843
https://tools.iana.org/public-view/viewticket/1364844
I have the BP community also reviewing this, but they are generally in
agreement as to use.
Thanks,
Scott M. Johnson
Spacely Packets, LLC
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Mark Andrews, ISC
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PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org
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