-----Original Message-----
From: Andrea Francini [mailto:francini@LUCENT.COM]
Sent: Friday, September 30, 2005 8:41 PM
To: STDS-802-21@listserv.ieee.org
Subject: Re: [802.21] [DNA] Prefix information for link
identification in DNA
Hi Yoshihiro,
I definitely don't mean to contradict what I wrote yesterday.
I still think of
the PoA as a link endpoint.
Your comment rightly brings up the necessity of providing a
clear definition of
"link" since link and PoA are tightly inter-related.
With a generic definition of PoA as a link endpoint, defining
"L2 PoA", "L3
PoA", and "MIH PoA" implies corresponding definitions of "L2
link", "L3 link",
and "MIH link".
I assume from now on that a layer-agnostic notion of link is
accepted and that
"link" is not strictly a Layer-2 notion. The group can debate
if this is a valid
assumption. If not (i.e., the group prefers to assign a
strong L2 flavor to
"link"), we can find a better term (e.g., "connection", or
"relationship") and
base on the new term both the generic and the specific
definitions of PoA. In
this latter case, "link" would be synonymous of "L2
connection" (or "L2
relationship", or whatever other term the group may identify).
I can think of the following generic definition for a
layer-agnostic link:
"Communication relationship for the exchange of messages
between adjacent peer
protocol entities."
Where:
"Peer protocol entities" always belong to the same protocol
layer (e.g., L2, L3,
MIH).
"Adjacent" emphasizes that there is no other interposed peer
entity between the
ones that terminate the link (e.g., there cannot be another
L3 entity between
the endpoints of an L3 link; if such entity is present, there
are two and not
one L3 links). This does not prevent a link from having more
than two endpoints:
in a multicast link, for example, all endpoints are adjacent
to each other and
none of them is necessary to enable connectivity between others.
The layer-specific definitions easily follow:
L2 link: "Communication relationship for the exchange of L2
messages between
adjacent L2 entities."
L3 link: "Communication relationship for the exchange of L3
messages between
adjacent L3 entities."
MIH link: "Communication relationship for the exchange of MIH
messages between
adjacent MIH entities."
Having the notions of "L2 link", "L3 link", and "MIH link" in
place, the PoA
definitions I previously proposed can easily be mapped as follows:
L2 PoA: network-side endpoint of L2 link involving the UE
L3 PoA: network-side endpoint of L3 link involving the UE
MIH PoA: network-side endpoint of MIH link involving the UE
As for identifying the endpoint entity as part of a network node:
The L2 PoA is an L2 interface on the network node, identified
by an L2 address.
The L3 PoA is an L3 interface on the network node, identified
by an L3 address
(on a router, the same physical interface can co-locate L2
and L3 interfaces).
The MIH PoA is an MIH interface on the network node, i.e., an
interface (either
L2 or L3) with which the MIH function of the network node is
registered for any
of the MIH services. When referring to both transport and MIH
capabilities of
the interface, we may have an "L2 MIH PoA" or an "L3 MIH PoA".
The main purpose of the endpoint vs. node distinction in the
PoA definition is
to avoid ambiguities when the same network node can terminate
multiple links and
present for each of them different capabilities and behaviors
(i.e., MIH
capability can be activated on one interface and not on
another, or the node can
be a hybrid L2/L3 box with both L2 ports and L3 ports).
Defining the PoA with
respect to a specific link (or connection) brings the focus of the PoA
definition on the functionality that the corresponding UE can
obtain from that
point in the network, without requiring any unnecessary
assumptions on the
overall nature of the network node that includes it.
While I am sure that the wording for the definitions I am
proposing can be
dramatically improved, I am convinced of the absolute
necessity to single out
the respective entities and provide clear definitions for
each of them.
Thanks,
Andrea
Yoshihiro Ohba wrote:
Andrea,
The PoA definition below is going to the direction that the
notion of
PoA is less associated with the notion of "link", as opposed to what
you made in your previous general statement which I have
fully agreed.
Or you may be introducing a new definition of "link" as "a specific
type of communication relationship", which seems to be too
ambiguous.
Yoshihiro Ohba
On Fri, Sep 30, 2005 at 11:25:04AM -0400, Andrea Francini wrote:
Trying to finalize one part of the ongoing discussion:
the PoA definition.
I have the impression that some people consider the
capability of supporting MIH
as part of the definition of PoA, while other people
don't, giving it only a
network connectivity value.
What about the following:
1. General definition of PoA:
a. "PoA is the first point in the network that acts as
the UE counterpart for a
specific type of communication relationship (e.g., L2, L3, MIH)."
2. Accordingly, the following three specific definitions
could be added:
b. "L2 PoA is the network-side endpoint of the L2 link by
which the UE connects
to the network."
c. "L3 PoA is the closest network counterpart for the UE
that requires an L3
address to be identified in UE-generated messages."
d. "MIH PoA is the closest network counterpart of the UE
for MIH exchanges."
Thanks,
Andrea
"Stefano M. Faccin" wrote:
Peretz, nobody denies that. The issue here is that what
you have been saying doe not allow for deployments that do
not use any MIH services at L2. Even if you may not believe
these deployments will happen, there are vendors and
operators that do believe that their networks will only use
MIH services at L3, at least for the initial deployments.
Thjerefore our model and definitions must allow for this. In
this model, there is no MIH @ L2, and the PoA is in the
subnet where the UE gets its IP address.
Stefano
________________________________
From: ext Peretz Feder [mailto:pfeder@LUCENT.COM]
Sent: Fri 9/30/2005 10:06 AM
To: STDS-802-21@listserv.ieee.org
Subject: Re: [802.21] [DNA] Prefix information for link
identification in DNA
"I do not understand how any one would conclude that
the MIH services are only between UE and the AP/BS."
The discussion is PoA and not services. The 1st PoA
could be L2 for IS and CS. With no PoA at L2, the poor UE
will have no MIH services until IP is established. The
performance will be very different, not to mention a UE with
a bridging only attributes, such as 802.16 terminal with only
Ethernet CS (no IP CS).
Nobody is saying MIH services are strictly between UE
and BS. Performance will be better when PoA L2 MIH is established.
Peretz
On 9/30/2005 10:50 AM, Srinivas.Sreemanthula@nokia.com wrote:
The MIIS is provisioned between MIH in UE to a
network counter part any
where in the network. This network node can
either act as a proxy info
server or an info server. We also identified
MIIS requires L3 and hence
the WG went through the exercise of identifying
all the UL requirements
and establish coordination with IETF. However,
in that discussion, there
was no reference to whether the AP/BS was MIH
or non-MIH capable.
Even if we leave out the info services from the
discussion, I do not
understand how any one would conclude that the
MIH services are only
between UE and the AP/BS.
-----Original Message-----
From: ext Peretz Feder
[mailto:pfeder@lucent.com]
Sent: Friday, September 30, 2005 9:39 AM
To: Sreemanthula Srinivas (Nokia-NRC/Dallas)
Cc: STDS-802-21@listserv.ieee.org
Subject: Re: [802.21] [DNA] Prefix
information for link
identification in DNA
Are you indicating attaching to a non
MIH enabled AP/BS and
receiving MIH IS over R4 from a remote
MIH info server?
On 9/30/2005 10:27 AM,
Srinivas.Sreemanthula@nokia.com wrote:
Did we miss the whole
discussion of MIH information services?
________________________________
From: ext Peretz Feder
[mailto:pfeder@LUCENT.COM]
Sent: Friday, September
30, 2005 9:16 AM
To:
STDS-802-21@LISTSERV.IEEE.ORG
Subject: Re: [802.21]
[DNA] Prefix information for link
identification
in DNA
"you have first to be
very clear about what you're attaching"
I would think that in
802.21, we first attach the UE's
MIH to a BS/AP
that supports MIH capability.
On 9/30/2005 8:55 AM,
Stefano M. Faccin wrote:
Mike, well said!
Stefano
________________________________
From: ext Mike
Moreton [mailto:mm2006@MAILSNARE.NET]
Sent: Fri
9/30/2005 3:09 AM
To:
STDS-802-21@listserv.ieee.org
Subject: Re:
[802.21] [DNA] Prefix information for link
identification in DNA
To extend (I
think!) Stefano's point, before
determining what the PoA
is, you have first to be very
clear about what you're
attaching. Just
saying "the terminal" makes no
sense, because different layers in the
terminal's protocol stack
attach to different places in the network.
For example,
the PHY layer attaches to the AP,
but the TCP layer
attaches to the destination host.
Mike.
-----Original Message-----
From:
Stefano M. Faccin
[mailto:stefano.faccin@NOKIA.COM]
Sent:
Friday, September 30, 2005 1:08 AM
To:
STDS-802-21@listserv.ieee.org
Subject: Re: [802.21] [DNA] Prefix
information for link
identification in DNA
Yoshihiro,
I'm not
sure why should restrict the
term PoA to have only a
L2
meaning as you suggest below. I
think we should
distinguish clearly between L2 PoA and L3 PoA.
For me, the L3
PoA is
where the terminal gets IP conenctivity.
E.g. for GPRS
the L3
PoA is the IP link on which the
GGSN is located. In
L2, PoA
is the point where the access-specific
L2 connection
terminates (e.g. an AP in 802.11).
Stefano