Dear All,
thanks for the feedback. We addressed it and uploaded a new version a minute ago: https://www.ietf.org/archive/id/draft-ietf-raw-ldacs-09.html
In order to identify the parts where we addressed the received feedback find it below in -line.
Regards,
Nils, Thomas, and Corinna
Von: Tal Mizrahi <tal.mizrahi.phd@xxxxxxxxx>
Gesendet: Mittwoch, 1. September 2021 12:11:59
An: rtg-ads@xxxxxxxx; draft-ietf-raw-ldacs@xxxxxxxx
Cc: rtg-dir@xxxxxxxx; last-call@xxxxxxxx; raw@xxxxxxxx
Betreff: RtgDir Last Call review: draft-ietf-raw-ldacsHello,
I have been selected as the Routing Directorate reviewer for this draft. The Routing Directorate seeks to review all routing or routing-related drafts as they pass through IETF last call and IESG review, and sometimes on special request. The purpose of the review is to provide assistance to the Routing ADs. For more information about the Routing Directorate, please see http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir
Although these comments are primarily for the use of the Routing ADs, it would be helpful if you could consider them along with any other IETF Last Call comments that you receive, and strive to resolve them through discussion or by updating the draft.
Document: draft-ietf-raw-ldacs-08
Reviewer: Tal Mizrahi
Review Date: 2021-09-01
Intended Status: InformationalSummary:
I have some minor concerns about this document that I think should be resolved before publication.
Comments:
The draft provides an overview of the L-band Digital Aeronautical Communications System (LDACS), which is a work-in-progress standard by the ICAO standardization group. The draft is well-written, and is almost ready for publication, with a few comments that follow.
Major Issues:
- Although the abstract clearly explains that LDACS includes support for IPv6, the reader later learns that LDACs is mostly a Layer 2 technology, and that IPv6 over LDACS has not been defined yet. The document does not describe the connection between LDACS and IPv6, why IPv6 was chosen (and not IPv4), and the challenges of using IPv6 over this technology. It would be worthwhile to add a paragraph or two about this to the introduction.
- We mentioned further regulatory document such as ICAO Doc 9896, RTCA DO-379, EUROCAE ED-262 and ARINC P858 all concerned with the foreseen ATN/IPS aeronautical communications backbone infrastructure in the introduction (Step (2) ...). IPv6 has been chosen as the basis for the ATN/IPS network and LDACS is a datalink access network technology from the view of ATN/IPS. This I highlighted also in the introduction.
- Specifically, it would be useful to add a paragraph that explains how LDACS is related to IETF protocols, and whether any work is expected in the IETF in this context.
- We added a paragraph at the end of the introduction, explaining the LDACS relevance in RAW and within the IETF.
Other Issues:
- Minor issues are concerns about clarity or technical accuracy that should be discussed and resolved before publication, but which would normally be resolved between the authors and the reviewers.
- Please include all of the minor issues you have found. Give as much context information as possible (e.g., section numbers, paragraph counts).
- If you find no minor issues, please write: "No minor issues found."
Nits:
- It would be useful to mention in the introduction in which parts of the world LDACS is expected to be deployed, and whether any geographical restrictions are expected in the context of this technology.
· We addressed that in the introduction (Step (1)... “Since central Europe has been identified as the area of the world, that suffers the most from increased saturation of the VHF band, the initial roll-out of LDACS will likely start there, and continue to other increasingly saturated zones as the east- and west-cost of the US and parts of Asia [ICAO2018]”).
- Throughout the document the word "shall" (lowercase) is used often. It is not clear whether this is because this text refers to the future tense, or whether because this is phrased as a requirement. I would suggest to replace the word "shall" by a different word, or to explain at the beginning what it means in this document.
· Apart from directly citing the security objectives in chapter 9.3. and from RTCA DO-350A document in the appendix A, we removed the word “shall” throughout the document.
- Abstract:
"High reliability and availability for IP connectivity over LDACS are therefore essential."
It would be useful to also mention security in this sentence.
· This is addressed now in the abstract.
- Introduction:
"efficient aircraft control and safe separation"
Please clarify what you mean by separation (perhaps separation between entertainment system traffic and aircraft control traffic?).
We clarified that by clearly stating “aircraft separation”. This is a term is used and widely known in aeronautics for ”…vertical and horizontal separation standards to facilitate the safe navigation of aircraft in controlled airspace” [ICAO Doc 4444 – Chapter 5].
- Introduction:
The following sentence is mentioned in Section 4. Maybe it would be useful in the introduction.
"LDACS standardization within the framework of the ICAO started in
December 2016. The ICAO standardization group has produced an
initial Standards and Recommended Practices document [ICA2018]."
· Thank you for the note, we moved it to the end of the introduction
- Section 3:
The term "Business Communication" is used several times. It would be useful to define what this means.
· We added a short explanatory sentence in chapter 3 for a clear definition of the term.
- Section 5:
The word "RECOMMENDS" (uppercase) is used here. This is not a standard RFC2119 key word. Please change it to lowercase.
· We changed all appearances of that word to lowercase.
- Section 5:
"Regulatory this is considered related to the safety and regularity"
Please consider rephrasing this sentence. It is not clear.
· We altered the sentence in chapter 5.2.4. for better understanding.
- Section 8:
"FL and RL boundaries are aligned in time"
Please mention what is the method used for synchronizing the time.
· We clarified this now by adding a mention of LDACS synchronization symbols in chapter 8.2. now.
- Section 9:
Figure 2 presents the LDACS protocol stack, where IPv6 is illustrated above the SNP layer. It would be useful to have some text in Section 9.5 that explains how the SNP layer is connected to the IPv6 layer, and why IPv6 is used here (vs. IPv4).
· We added a paragraph clarifying the issue in chapter 7.3. (second paragraph).
- Section 10:
"Reasons for Wireless Digital Aeronautical Communications"
This title does not really fit the section - please consider rephrasing it.
· We changed it to “Security in Wireless Digital Aeronautical Communications” and also changed the content of the section slightly to fir the title. As we relocated some parts of the text to other sections you can find this part now adressed within Section 9
- Section 10.2:
Typo: LADACS ==> LDACS
· We
changed this unfortunate typo. Keep in mind Section 10 is now
section 9 due to relocation of text parts.
- Section 11:
"Privacy Considerations"
The text in this section is not related to privacy. I would suggest removing this section completely.
· We removed this section.
- Reference section:
Please review the "normative references" section. I would move all the references to "informative", unless you find that one of these is absolutely required as normative.
· We
changed the order of bibliography: Now only regulatory documents
or the ICAO specification
of LDACS are stated as normative reference, while the rest has
been declared
informative references.
- Please remove [RFC2119], as it is not used in the document.
We removed unused references.
-- ****************************************************** PD Dr. rer. nat. habil. Corinna Schmitt Head of Secure IoT Research Institute CODE Universität der Bundeswehr München Werner-Heisenberg-Weg 39 85577 Neubiberg, Germany Email: corinna.schmitt@xxxxxxxx https://www.unibw.de/code https://www.corinna-schmitt.de
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