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Draft notes from IETF-64 - For comment.
I enclose a copy of the draft notes from the ipdvb WG meeting at IETF-64.
The notes were taken by Martin, with contributions from a few others and the
audio record.
Please check for accuracy. If you have any comments or queries, please do
send to me and/or the list!
Best wishes,
Gorry Fairhurst.
(ipdvb WG Chair)
----
Minutes of the IP over Digital Video Broadcast WG (IPDVB)
===========================================================
TUESDAY, 13:00-15:00 November 8, 2005
Chair: <gorry@erg.abdn.ac.uk>
WG Note-taker: Martin Stiemerling <stiemerling@netlab.nec.de>
1. Agenda
---------
(WG Chair, Gorry Fairhurst)
This was the 5th meeting of the IPDVB WG at the IETF. The meeting was
chaired by Gorry Fairhurst. The proposed agenda was accepted. An
additional presentation by Axel Jahn on IP over DVBS.2 had been
received, which the WG Chair would present.
2. Document Status
------------------
(WG Chair, Gorry Fairhurst)
Active WG Drafts:
draft-ietf-ipdvb-ule-06.txt (Proposed Standard)
RFC Editor queue in EDIT IANA.
draft-ietf-ipdvb-arch-04.txt (Informational)
RFC Editor's queue in Auth48 call.
draft-ietf-ipdvb-ar-01.txt
Active WG draft.
Protocol entries for ULE has been created in registries at:
- ISO/SMPTE
- ATSC
- IANA Next-Header registry
These registry assignments are now permanent.
Other related documents Individual Drafts for consideration by WG:
draft-stiemerling-ipdvb-config-01.txt
draft-cruickshank-ipdvb-sec-req-00.txt
draft-cruickshank-ipdvb-sec-00.txt
draft-cantillo-ipdvb-s2encaps-01.txt
There had been a re-charter of the WG Charter milestones, after
the last IETF meeting. A new item added on ULE security requirements.
The new milestones are progressing well and all completed on time.
3. Presentation on IP Address Resolution
----------------------------------------
(draft-ietf-ipdvb-ar-01.txt) Marie-Jose Montpetit
Marie-Jose presented an overview of the document structure and noted
that this must work in all MPEG-2 networks: address resolution should
be technology agnostic. The I-D was to: Define terminology, lead to
a common understanding, review implementation scenarios. Address
resolution should also be considered above IP and the goal is how
to make the implementation more IP friendly.
The I-D is applicable to whatever MPEG-2 transmission is used
(satellite, cable, handheld, ...) and presents methods to ensure AR
is network-aware / technology agnostic (mobility of solutions) and
speaks about integration into multiple signaling paradigms: DVB-SI
and IMS/SIP; This can resolve other parameters: encapsulation method,
MTU, policy/priority/QoS, security, packing threshold.
The current revision -01 is now in good shape. Updates include:
- Added description of use of SI.
- Various things based-on discussion on the list.
- Fixes to document format.
She presented the intended work for I-D rev. -02:
- Investigate integration into other new trends:
SIPPING, ipconfig, autoconf;
- Closer integration into other standards bodies;
- Inputs are requested from the WG on mobility, DVB-H, IMS;
- Also: cable/broadcast strategies usage, IP streaming over MPEG-2.
Gorry Fairhurst: There are a lot of things that could be added.
How long until the I-D is ready for a WGLC?
Marie-Jose Montpetit: This is some kind of shopping list, we propose
to cycle it one or two more times, and get comments from the list.
The I-D should be ready by early next year.
Gorry Fairhurst: The milestone is March 2007.
Marie-Jose Montpetit: Seems OK.
Gorry Fairhurst: I encourages people to read next draft, and offer
contributions where able.
4. Presentation on IP Address Configuration
-------------------------------------------
(draft-stiemerling-ipdvb-config-02) Martin Stiemerling
There has been progress, the I-D has been reorganised, and is now
ready for comments from the WG. Open issues include the configuration
parameters, sets of configuration items, and how to reconfigure?
The I-D still needs to differentiate between the configuration roles
of the MPEG-2/DVB operator and IP operator. There is no current
conclusion on whether new protocols are needed?
Marie-Jose Montpetit: The I-D speaks about MPEG-2/DVB and IP operators.
What about content provider configuration?
Martin Stiemerling: That's a good question.
It should enter the picture somewhere.
Marie-Jose Montpetit: All these people have configuration.
Martin Stiemerling: If we talk about IP-level questions, then I am
not sure they are involved, if this is at the service-level, then
there is configuration.
Gorry Fairhurst: Does anyone have NDP experience in very flat networks
- i.e. scalability to large numbers of systems?
Marie-Jose Montpetit: The Secure Neighbor Discovery WG (send) has
work on scaling, captured in an RFC. This is important to the AR I-D.
Martin Stiemerling: I will look into this point.
Gorry Fairhurst: Is the I-D heading towards an Informational RFC.
Should the outcome be part of another I-D?
Martin Stiemerling: There can be recommendations on DHCP, NDP, arp, etc.
Gorry Fairhurst: This seems to fall within the Chartered item on
Address Resolution. We may finally need to consider whether this I-D
should be combined with the AR draft. For now, I am very happy to see
the I-D proceed, and would like to see contributions.
5. Presentation Security Requirements
-------------------------------------
(draft-cruickshank-ipdvb-sec-req-00) Sunil Iyengar
A security I-D had been presented at IETF-63 (in Paris). The
proposed L2 security method is based on an analysis of ULE. It had
received many good comments at the previous meeting, but also some
important questions from the IETF Security Area. This new I-D
responds to these comments. It mainly describes threats and security
requirements. The L2 security association is between an Encapsulation
Gateway and the Receiver.
A number of issues have been brought up on the mailing list. The
authors are reading these and intend to work through them on the
mailing list after the IETF meeting. The intention is to revise the
document in December 2005, collect more feedback, and finally ask
the WG to adopt it against the new Milestone.
Martin Stiemerling: The document is about ULE security.
Why is NAT in the L2 security document?
Sunil Iyengar: ULE security does not impact NAT functions, but we
need to ensure the security framework is compatible with NAT functions.
Martin Stiemerling: On some links, there is no NAT.
Gorry Fairhurst: I requested a work-item on ULE security requirements.
Should it have been on IP security requirements when using DVB/MPEG?
If so I may have requested the wrong name for the Milestone, we should
see how the I-D develops and look at the current Milestone.
Gorry Fairhurst: So, the NAT issue is more of an IPsec issue, than a
ULE issue?
Sunil Iyengar: Yes, just that.
Martin Stiemerling: So the security requirements go beyond just ULE?
Gorry Fairhurst: Yes. Specifically we were asked to talk about IPsec,
bulk link encryption. Link encryption. This was requested at IETF-63.
Martin Stiemerling: This needs to be explained in the title or elsewhere.
Marie-Jose Montpetit: The authors appear to come from the satellite
community. There are other MPEG-2 networks that could use ULE.
Are there plans to extend the involved folks beyond satellite?
Sunil Iyengar: Yes, it would be helpful. If you have expertise
or requirements, please do contact us, we're looking for contributions.
Marie-Jose Montpetit: A title change to MPEG/DVB security would help,
and help encourage more contributions.
Gorry Fairhurst: I'd like to see the scope as what needs to be done
to make the Internet security service secure, and what needs to be
done below the Internet layer to make this happen.
Gorry Fairhurst: There was discussion on L2 signaling on the list
(originally looking at AR). Is this topic ready to be summarised?
Sunil Iyengar: Yes, I will send something to the list tomorrow,
and will talk about what authentication means in this context.
6. Presentation Security Method
-------------------------------
(draft-cruickshank-ipdvb-sec-00) Sunil Iyengar
This was the same I-D that had been presented at IETF-63. The authors
will keep this draft alive while the requirements I-D matures, and
update it. There will a new version -01 at the end of January 2006.
7. DVB-S.2 Framework
--------------------
(WG Chair, Gorry Fairhurst)
Gorry presented one slide showing the position of the new DVB-S.2
physical-layer within the protocol stack. This was expected to
become a widely deployed standard and support existing ULE, MPE, etc
via a transport stream interface. There was also a direct mapping
of IP packets into the physical layer, known as the Generic Stream.
This was under study in DVB-GBS, and was the topic for the next few
presentations. There is an opportunity here to ensure that the two
modes of DVB-S.2 have a common IP interface (e.g. based on ULE).
7.1 DVB-S2 Encapsulation GBS Activities
-----------------------------------------
(prepared by Axel Jahn, presented by Gorry Fairhurst)
Axel was responsible for S.2 IP Encapsulation work within DVB-GBS.
The presentation described how DVB-GBS intends to define S.2
encapsulation requirements and evaluation criteria (see slides).
The IP/S.2 group will send a copy of their document to the ipdvb
mailing list. The group is asking for potential encapsulation methods.
Next year, the comparison and evaluation would start. Many ipdvb WG
members are already participating in this process, others are welcome
via a DVB member.
7.2 Requirements for IP over DVB-S.2
------------------------------------
(draft-cantillo-ipdvb-s2encaps-01) Juan Cantillo
Juan presented a framework for IP encapsulation using Generic Streams.
This version of the I-D has been completely rewritten, based on
comments on and off the list. He presented a list of pending issues
concerning the I-D. The next step is to propose this as a WG item.
This is a hot topic, but does the WG scope cover DVB-S.2?
Martin Stiemerling: What is the fragmentation problem?
Juan Cantillo: ULE fragments SNDUs in MPEG-2, in S.2 BBframes have
no defined method for flexible fragmentation.
Martin Stiemerling: We already have ULE, is fragmentation out of scope?
Gorry Fairhurst: I'm not sure this is the same problem, let's take
questions about scope later.
Josef Schmidbar: Are there any plans to utilize the different
modulation options and link these to the IP QoS?
Juan Cantillo: I am not aware of any work yet, most current systems
also use MPEG-2 at constant rate. QoS could be added to the I-D.
The authors would welcome ideas and text for this.
Mark Watson: What is the relation between physical layer FEC and
packet-level FEC? The physical layer is not necessarily the best place
to expend effort to ensure overall reliability. Can the whole stack
be optimised?
Juan Cantillo: We are hopeful about driving ideas on cross-layer
optimizations between L2 and L3. This topic needs to explored, and has
many implications on IP. We are not yet talking about application
optimisation, this is in the longer term.
Gorry Fairhurst: You are bound to consider about applications/transport
if you need to understand the loss/error requirements of specific flows.
acket FEC, is now an important IETF Transport Area topic, with
documents in AVT and RMT WGs, and a BoF this IETF (FECFrame). This WG
is not the only place in the IETF to address this topic.
Juan Cantillo: There are potential some tools in S.2, that we can use
for example the ISI field.
Gorry Fairhurst (WG Chair): The Charter defines what the WG should
do. Any change needs to be discussed with our Area Director (and
the IESG). Anyway, the WG should not duplicate what is done in another
organisation. Axel's contribution seems to clarify things. It seems
to methat the I-D is more focussed on IP and there is no overlap.
This may compliment work in DVB-GBS by bringing Internet experience.
How many had read draft-cantillo-ipdvb-s2encaps-01?
(6 people had read the document)
How many people think the WG has expertise to work on this topic?
(6 people had read the document)
The authors should continue to revise this I-D, and the WG should
pursue this topic on the mailing list. The protocol specification
is not a valid WG item: It would therefore be premature to propose
any Milestone in this space within the ipdvb WG.
8. ULE Implementation Status
----------------------------
(WG Chair, Gorry Fairhurst)
Gorry presented a list of known implementations. Once ULE is
published as an RFC, implementors should be encouraged to bring their
code up to the proposed standard. There is another new implementor
working on trial open source for a ULE Gateway. No details were
available yet, but we should expect an announcement in a few months,
this will complement the existing open-source Receiver. He asked if
there were any news from other implementors?
Josef Schmidbar: University of Salzburg had contributed to the Linux
ULE release (now a standard feature of the kernel), and had recently
discovered a small bug. The treatment of the D-bit (destination NPA/MAC
address suppressed) was wrong when D=0 (specified MAC/NPA address) and
a multicast L2 address was used. This could lead to unexpected packet
loss for IPv4/IPv6 multicast.
Gorry Fairhurst: Was this implementation going to be fixed?
Gorry Fairhurst: Yes, and it would be uploaded to the Linux
distribution.
27 people were in the meeting room, and some also participated via
jabber/audio. The session ended at 2:30pm.