I am in favor of leave it out completely, then. The reason is that
the feature of changing PAA address with continuing the PANA session
seems to have general applicability in addition to the relay use case.
I think "less is more" design philosophy can be applied here.
Yoshihiro Ohba
(2010/12/02 0:18), Robert Cragie wrote:
Hi Rafa,
I agree it is not relevant relevant for *switching* to non-relay
operation but may be necessary to continue a session when
communicating directly (in an IP sense) with the PAA.
I suggest we either leave it out completely:
"If direct IP routing becomes available and the PaC is notified about
the PAA's IP address using an out-of-band mechanism that is not
specified in this document, the PaC may choose to directly communicate
with the PAA without use of the relay operation."
or change it to the following to suggest it may still have a place:
"If direct IP routing becomes available and the PaC is notified about
the PAA's[ IP address using an out-of-band mechanism that is not
specified in this document, the PaC may choose to directly communicate
with the PAA without use of the relay operation. The PaC IP address
update procedure defined in [RFC5191] may additionally need to be
performed using[1] the directly reachable IP address of the PAA."
[1] "be performed to switch to non-relay operation, using" -> "need to
be performed using"
Robert
Robert Cragie (Pacific Gas & Electric)
Gridmerge Ltd.
89 Greenfield Crescent,
Wakefield, WF4 4WA, UK
+44 1924 910888
+1 415 513 0064
http://www.gridmerge.com <http://www.gridmerge.com/>
On 01/12/2010 2:30 PM, Rafa Marin Lopez wrote:
Hi all,
my apologies for answering a bit late to this.
I do not completely understand the sentence:
"The PaC IP address update procedure defined in [RFC5191] may
additionally be performed to switch to non-relay operation, using
the directly reachable IP address of the PAA."
I think that the PaC IP address update procedure defined in
[RFC5191] is useless for this scenario where the PAA "changes" its
IP address. I believe what PaC must simply do is to update the IP
address in the PANA session with the PAA's IP address obtained with
this out of band mechanism.
This, my suggestion would be to remove that sentence.
Best regards.
El 01/12/2010, a las 14:50, Robert Cragie escribió:
Maybe I'm missing something but switching to direct communication
has nothing to do with a *change* in the PAA address. I would
suggest the following:
"If direct IP routing becomes available[1] and the PaC is notified
about the PAA's[2] IP address using an out-of-band mechanism that
is not specified in this document, the PaC may choose to directly
communicate with the PAA without use of the relay operation. The
PaC[3] IP address update procedure defined in [RFC5191] may
additionally[4] be performed to switch to non-relay operation,
using the directly reachable IP address of the PAA."
[1] Removed ZigBee IP reference
[2] "the change of PAA's" -> "the PAA's"
[3] Added PaC as per Alper's suggestion
[4] Added "additionally" as this is independent from getting the
PAA address
Comments?
Robert Cragie (Pacific Gas & Electric)
Gridmerge Ltd.
89 Greenfield Crescent,
Wakefield, WF4 4WA, UK
+44 1924 910888
+1 415 513 0064
http://www.gridmerge.com <http://www.gridmerge.com/>
On 30/11/2010 9:20 PM, Alper Yegin wrote:
Looks good to me.
One minor update:
"The IP address update procedure" --> "PaC IP address update procedure"
Alper
-----Original Message-----
From: Yoshihiro Ohba [mailto:yoshihiro.o...@toshiba.co.jp]
Sent: Tuesday, November 30, 2010 3:52 AM
To: Alper Yegin
Cc: 'Rafa Marin Lopez';pana@ietf.org; 'Ralph Droms';
robert.cra...@gridmerge.com; 'Samita Chakrabarti'; 'Paul Duffy
(paduffy)'
Subject: Re: Switching to direct communication [was Re: PANA relay
draft]
OK. How about the following change?
Current text:
"If direct IP routing becomes available (e.g., after the successful
PANA authentication as in the case of Zigbee IP), the PaC may
choose to directly communicate with the PAA without use of the relay
operation. The IP address update procedure defined in
[RFC5191] may be performed to switch to non-relay operation."
Propose text:
"If direct IP routing becomes available (e.g., after the successful
PANA authentication as in the case of Zigbee IP) and the PaC is
notified about the change of PAA's IP address using an out-of-band
mechanism that is not specified in this document, the PaC may choose
to directly communicate with the PAA without use of the relay
operation. The IP address update procedure defined in [RFC5191] may
be performed to switch to non-relay operation, using the directly
reachable IP address of the PAA."
Yoshihiro Ohba
(2010/11/29 21:10), Alper Yegin wrote:
Rafa,
El 26/11/2010, a las 08:21, Alper Yegin escribió:
Let me create a new thread on this specific topic.
It has been identified that switching from relay to direct
communication requires not only change of PaC's address but also
change of PAA's address.
But RFC 5191 supports change of PaC's address for a given PANA
session
but does not support change of PAA's address.
Yes, RFC 5191 has an explicit support for that.
So it seems that switching to direct communication requires to go
through a full PANA authentication.
I don't think that's necessary at all.
If the PaC learns another (or new) IP address of the PAA by some
out-
of
scope mechanism, then it can start using that IP address. And
that's
the
case in Zigbee.
[Rafa] What I believed is that a new PANA authentication was
necessary
when you switch the PAA's interface, as Yoshi has mentioned. It does
not mean that it is the best option of course, but what happens is
that
there is no support for PAA's address change. I believe this
scenario
was not considered in RFC 5191.
We didn't envision this scenario. Hence RFC 5191 is "silent" about
it.
In other words, there is no explicit facility to realize that (PAA IP
address change), and there is no prohibition against it either. Which
means,
if some implementation/SDO/deployment can figure out a way to enable
that
w/o breaking the RFC, it's OK. And that's the case with this Zigbee
Alliance
usage.
In the same way that "In order to
maintain the PANA session, the PAA needs to be notified about the
change of PaC address.", I would expect a mechanism saying that: "In
order to maintain the PANA session, the PaC needs to be notified
about
the change of PAA address."
We can say something to that affect in the relay I-D.
Alper
Alper
So if we mention "direct IP routing MAY be available" then we may
also
need to mention that "switching to direct communication requires a
full PANA authentication using the new PaC's and PAA's addresses."
What do you think?
Yoshihiro Ohba
(2010/11/24 21:32), Alper Yegin wrote:
[Rafa] In my opinion, after the successful PAA authentication, I
believe that it would be better that PaC does not require the
PRE
anymore. In other words, the PaC and the PAA know each other.
Moreover
I assume that after the successful PAA authentication the PaC
will
be
able to contact directly the PAA without the assistance of the
PRE.
If
these assumptions are reasonable, there will not be PAA-initated
messages that go through the PRE.
I think this spec shall not mandate or prohibit use of PRE after
the
first
successful PANA auth. Spec shall allow both, and the consumers
(deployments,
architectures) shall decide.
If direct IP routing becomes available (e.g., after the
successful
PANA authentication as in the case of Zigbee IP),
[Rafa]. Is the PRE informed by the PAA?. If it is, how?. In
other
words, how is this enabled after a successful PANA
authentication?
The PRE is not informed by the PAA when direct IP routing
becomes
available.
[Rafa] I mean that it is mentioned that direct IP routing is
available
, how is this enabled after a successful PANA authentication? is
the
PaC enabled to use a non link-local IPv6 address?.
I think the spec shall say "direct IP routing MAY be available".
In
the
specific case of zigbee, PaC receives RA and configures a global
IPv6
address. Such details belong to zigbee spec.
On the other hand, what entity is acting as EP?.
An EP may reside in the PRE, or it could be a separate entity
from
the PRE.
the PaC may choose
to directly communicate with the PAA without use of the
relay
operation.
[Rafa] However, it has been said that PaC that "From the PaC's
perspective, the PRE appears as the PAA."
This sentences seems to mean that PaC knows that it is talking
with
a relay first.
The PaC may not know that it is talking with a relay first.
OTOH,
the PaC may know, after successful PANA authentication, that it
was
talking with a relay, by using some out-of-band mechanism. But
this
does not mean that switching to direct communication is needed.
The
point here is that we try to describe possible cases as much as
possible.
The IP address update procedure defined in [RFC5191] may
be performed to switch to non-relay operation.
[Rafa] Who is sending this notification?
The notification is generated locally by the node that has
updated
an
IP address.
[Rafa] What is that node? the PAA? the PaC? both?. I mean to
switch
to
non-relay operation, under PaC point of view the PAA is
switching
the
IP address (PaC thought the PAA was the PRE but now it is the
real
PAA)
That's right. Both PaC's and PAA's IP address are changing for
the
given
PANA session.
-------------------------------------------------------
Rafael Marin Lopez, PhD
Dept. Information and Communications Engineering (DIIC)
Faculty of Computer Science-University of Murcia
30100 Murcia - Spain
Telf: +34868888501 Fax: +34868884151 e-mail:r...@um.es
-------------------------------------------------------
-------------------------------------------------------
Rafael Marin Lopez, PhD
Dept. Information and Communications Engineering (DIIC)
Faculty of Computer Science-University of Murcia
30100 Murcia - Spain
Telf: +34868888501 Fax: +34868884151 e-mail: r...@um.es
<mailto:r...@um.es>
-------------------------------------------------------
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