Re: [802.21] [DNA] Prefix information for link identification in DNA
Hello Mike,
Questions: What is benefit of having a generized definition of link?
In terms of handover decision making, should we define "link* up"
events for a "link" between a UE and an MIH Information Server that
may be tens of IP hops away from the UE?
Yoshihiro Ohba
On Mon, Oct 03, 2005 at 08:58:15AM +0000, Mike Moreton wrote:
> Andrea,
>
> I really like these definitions - I think they are clear and precise, which gives a good basis to argue from.
>
> Which is what I'm going to do!
>
> I think the link between two adjacent layer 3 entities is actually a layer 2 link. To me, the purpose of any link at layer N is to provide a PDU transfer service to layer N+1.
>
> If you took your definitions as they are, then the layer 3 link coming up would not allow TCP or UDP to flow - you'd still have to wait for IP address assignment - and that sounds wrong to me.
>
> Mike.
>
>
>
> > -----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
> > > > >
> > > > >
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