Ian, all,
Ian, thanks a lot for your fast reply and detailed commenting on the
"6LoWPAN Mesh Routing Requirements" draft
[http://www.ietf.org/internet-drafts/draft-dokaspar-6lowpan-routreq-00.txt].
I'm taking the right to post this answer to both the 6lowpan and MANET
working groups, as MANET folks might be interested in this discussion as
well.
Ian, I find your inputs very reasonable, but they made me feel that the term
"6lowpan" is not yet defined precisely enough to set up a strict set of
6lowpan routing requirements. For example, you give me the scenario of a
6lowpan network, in which all devices are powered and power usage is not
important. But if I read the "6lowpan Problem Statement"
[http://tools.ietf.org/wg/6lowpan/draft-ietf-6lowpan-problem], I'm not sure
if such a set-up could still be called a 6lowpan, because that document
explains that in a LoWPAN "typically, some or all devices are battery
operated."
This draft's intention is to provide the primary design goals of 6lowpan
mesh routing and to stimulate responses for defining a set of requirements.
The requirements I listed are still as vague as the term "6lowpan" itself,
not at all proven and not fixed yet. I will keep all of your detailed
comments on the requirements in mind for a next revision. Also, it has
already been my intention to include a Section about what exactly the
differences are between routing in a MANET and in a LoWPAN.
Best regards,
Dominik
----- Original Message -----
From: "Ian Chakeres" <[EMAIL PROTECTED]>
To: "Dominik Kaspar" <[EMAIL PROTECTED]>
Cc: <[email protected]>
Sent: Thursday, March 01, 2007 2:00 AM
Subject: Re: [6lowpan] For comments: 6LoWPAN Mesh Routing Requirements
Good to see some requirements for 6lowpan routing.
Personally, I'd like to know what can't be done with MANET protocols
and why. Hopefully, a future version will include this information. If
you have any comments please send them to me or the MANET list.
Ian
I have some quick comments about the document.
I don't think LQI by itself should be used. LQI must be matched with
other indicators to make good decisions. LQI can be bad for routing.
Similarly, shortest path can be bad.
I think that operating with low routing state should be an
additionally goal. For example, if devices have only 32 forwarding
entries available. This fact could probably be captured in one of the
existing sections.
Regarding the requirements section:
I think that R2 is a bad requirement. I would instead say that routing
should be efficient. Efficiency can be defined in many ways. There
might be 6lowpan networks where all devices are power so power usage
is not important. Alternatively there might be nodes that choose not
to participate even though they have energy. I think that requiring
minimal energy routing is too harsh and unrealistic.
R3. I would say that 6lowpan works below IP. Therefore,
interconnection is not seamless but below IP. Some device will need to
bridge (PAN coordinator or gateway) this gap. For example, RFD edge
devices will likely not include this capability.
R4. I'm not sure that routing needs to be aware of sleeping nodes. We
could reverse the requirement and say that sleeping nodes must be
aware of routing. Or we could create a routing protocol that should
work independent of the sleep schedule. For example, flooding.
R5. How do we measure simplicity and robustness? How much simplicity
and robustness are required by the various 6lowpan players?
R6. How mobile? How dynamic?
R7. Are you referring to IPv6 ND or routing (L2 in this case)
neighbor(hood) discovery?
R9. What is the scalability requirement? How many nodes & at what density?
R10. Is L2 (WEP like) security enough?
Ian
On 2/27/07, Dominik Kaspar <[EMAIL PROTECTED]> wrote:
Hi all,
A new Internet-Draft has just been submitted to emphasize the importance
of
mesh routing in LoWPANs. I believe that well thought-out mesh routing is
a
vital precondition for fully functional LoWPANs and should be discussed
in
more detail within the 6lowpan working group.
Comments are welcomed for the Internet-Draft titled:
"Design Goals and Requirements for 6LoWPAN Mesh Routing"
Abstract:
This document defines the problem statement, design goals, and
requirements
for mesh routing in low-power wireless personal area networks (LoWPANs).
A URL for this Internet-Draft is:
www.ietf.org/internet-drafts/draft-dokaspar-6lowpan-routreq-00.txt
Best regards,
Dominik
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