Re: [802.21] Question today about upper layers
Let's change a bit the aspect of the discussion...
About standardization:
- An element (information, protocol, function, etc) needs to be standardized
ONLY IF its behaviour and/or format needs to conform to an agreement (for
interoperability). There are conformance testing of protocol
implementations, but there are no conformance testing for SAP
implementations (although well-know APIs can be specified and implemented).
- The SAP is a means in standards to describe the abstract relationship
between a service user and the service provider in the adjacent layers in a
reference model of a protocol stack. It is NOT used to describe (protocol)
exchanges between systems. It does NOT dictate any implementation of the
layers and APIs. The SAP describes the essential abstract primitives
(request, response, indication, response) with their associated parameters
(formats and semantics) between the service user and service provider. How a
SAP is implemented could be specified in an API, which decides how to
express the SAP primitives in function calls and methods (synchronous,
asynchronous, callback, listening, etc), and may include other elements
associated with specific software design, OS, and programming language.
Now about the mobility management policy:
- Is there a need to standardize the logic of processing a mobility
management policy? I don't think so. There is no interoperability issue
associated with such logic.
- Is there a need to standardize the expression of a mobility management
policy? It is ONLY necessary if a protocol is to be defined to exchange such
policy between systems. I do see such need. However, I don't think such
exchange as part of the 802.21 (MIH) function; thus such policy expression
does not needed to be exchange at the MIH SAP between layers; thus the
policy expression does not need to be standardized in 802.21 (although it
may need to be standardized else where).
- I do not see any argument from the standardization perspective justifying
the need of standardizing policy and policy logic in 802.21. As pointed out
already, this does not prevent any such policy and policy logic to be
implemented.
Cheers,
Hong-Yon
[Gupta, Vivek G]
It just cannot be standardized that way. If it is not standardized that
way no possibility is precluded and you are free to do your own custom
implementation any way you want.
PF: Are you saying it can't be standardized because it can't be tested? and
therefore nothing is precluded?
[Gupta, Vivek G]
With only the base primitives of triggers and information service
PF: and these are testable/conformable and therefore can be standardized
more
precisely?
On 21/03/05 20:24, "Johnston, Dj" <dj.johnston@INTEL.COM> wrote:
> If we can agree that policy attribute signalling is complex and hard to
> standardize, why not do as other groups do and leave in plenty of room
> for vendor proprietary primitives and messages? Give it a year or two
> and implementors will better know what works and be in a position to
> propose specifics.
>
> Obviously, since I'm suggesting a vendor proprietary message ID space on
> the wire/air (as per the original proposals in the ECSG), I don't mean
> upper layers only. These things may or may not need to traverse the
> link.
>
> I'm trying to understand the argument. Does someone want policy
> attribute primitives defined and someone else not? Or is it one of these
> arguments that is ultimately moot because it has no impact on the text?
>
> DJ
>
>
> -----Original Message-----
> From: owner-stds-802-21@LISTSERV.IEEE.ORG
> [mailto:owner-stds-802-21@LISTSERV.IEEE.ORG] On Behalf Of Stefano M.
> Faccin
> Sent: Monday, March 21, 2005 6:15 AM
> To: STDS-802-21@LISTSERV.IEEE.ORG
> Subject: Re: [802.21] Question today about upper layers
>
> -----Original Message-----
> From: owner-stds-802-21@LISTSERV.IEEE.ORG
> [mailto:owner-stds-802-21@LISTSERV.IEEE.ORG]On Behalf Of ext Peretz
> Feder
> Sent: Monday, March 21, 2005 12:17 AM
> To: STDS-802-21@LISTSERV.IEEE.ORG
> Subject: Re: [802.21] Question today about upper layers
>
>
> On 3/15/2005 9:57 AM, Iyer, Prakash wrote:
>> We might want some flexibility here. Having a lower layer autonomously
>
>> switch links w/o considerations for cost ($$), whether it makes sense
>> to single-home or multi-home, account for user preferences etc. does
>> not seem appropriate - and certainly not in all situations. Having MIH
>
>> generate triggers that facilitate handovers is one thing; specifying
>> how MIH can use policies to switch links at this layer is avoidable in
>
>> 802.21.
> Not sure what is issue. Why can't the MIH layer get as one of its inputs
> the policy attributes? Why is it (policy attribute) only reserved for an
> upper layer?
> [Stefano Faccin] Peretz, I believe the point here is not that policies
> and policy attributes must be only reserved for the upper layer, but
> that realistically it would be rather complex to specify a SAP that
> allows the UL to provide all the relevant attributes. Through
> experimenting in Nokia implementations of mobility/connectivity
> management for multiple access devices, we've witnessed that in order
> for a terminal with multiple policies - end user, device owner (e.g.
> enterprise), WISP, cellular operator, application policies/requirements
> - to make decisions on connectivity and handoff, a rather complex set of
> interactions between the information available about the links and the
> policies is required. This led to the conclusion that the logic driving
> such interaction must be at a layer above the MIH, since such logic can
> be very complex. Also, it does not make much sense in specifying such
> logic but allow differentiation between vendors. In particular, we
> experienced how com!
> plex the interactions between this logic and the policies are, and as a
> direct result if we wanted to allow any logic in the MIH function and
> the most flexible interaction between the MIH and the policies
> repository in the terminal, a very complex SAP would result. In
> conclusion, I see a lot of added complexity without seeing much
> advantage.
>
> That said, with the base primitives, none of the implementation
>> scenarios that people are thinking about will be precluded.
>
> Please elaborate, are you referring to upper layer implementation only
>
>> -Prakash
>>
>> -----Original Message-----
>> From: owner-stds-802-21@LISTSERV.IEEE.ORG
>> [mailto:owner-stds-802-21@LISTSERV.IEEE.ORG] On Behalf Of Peretz Feder
>> Sent: Monday, March 14, 2005 2:48 PM
>> To: STDS-802-21@LISTSERV.IEEE.ORG
>> Subject: Re: [802.21] Question today about upper layers
>>
>> Greg:
>>
>> I am of the opinion thet MIH commands lower layers to switch a link
>> and in conjunction inform upper layers to take care of the IP
>> signaling over the new selected link.
>>
>> Example switch 3gpp2 to .11 interface and make the MIP signaling at
>> layer 3 perform MIP re-registartion with the new COA and old MIP
>> address. So I am with you.
>>
>> The counter argument will be what if moblity is done at the
>> Application layer?
>> i.e. SIP mobility?
>>
>>
>>
>> Peretz Feder
>>
>>
>>
>> On 3/14/2005 5:12 PM, Greg Daley wrote:
>>
>>> Hi,
>>>
>>> Here's my question from today about
>>> upper layer protocols.
>>>
>>> Have you considered if specifying direct interfaces to upper-layers
>>> will cause confusion?
>>> Wouldn't it be better to delegate this upper-layer trigger function to
>
>>> L3?
>>>
>>> Greg
>>
>
Message Classification:
[ ] General Business Use Only
[ ] Motorola Internal Use Only
[ ] Motorola Confidential Proprietary
Hong-Yon Lach
Lab Manager, Edge Mobile Networking Lab (EMNL)
Office: +33 (0)169352536; Mobile: +33 (0)607590268
Parc les Algorithmes - Saint Aubin
91193 Gif-sur-Yvette Cedex
France