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Re: [802.21] [Mipshop] Re: Architectural Considerations for Handover InformationServices



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  • I am not sure that we really need to specify a “transport” for IS. The reason is that... It is very likely that a mobility management protocol would need exchange of certain information between the terminal and the network in order to perform mobility management. Depending on how the mobility management protocol is specified and based upon, it is very likely that the information exchange will be integrated in the mobility management operation for optimal performance. Thus, while a generic “transport” for IS could be specified, it is not desirable that it is mandated to be used, as the IS exchange may be better incorporated in other operations. Therefore, it appears to me to be more important to define the various pieces of information that could be needed for IS exchanges.
            I agree with you that we need to define the information first and we will do it. However, I  don't think it is a good idea  to combine the transport of the information with  the mobility protocol. .21 IS
              must work  irrespective  of mobility protocol choice and in fact  information exchange should happen even before mobility protocol kicks in.

[hong-yon] I am not suggesting what is better, it all depends. I just feel that such flexibility and choice is necessary to allow people to determine the necessary mobility management scheme for their systems. This discussion could be senseless as it is still not clear what information we are talking about for IS. Here is my opinion: if the information in IS are concerned only with the need of exchanges to help the various entities (terminal, network) to determine the link status/condition, then I agree that the IS should be completely independent of mobility management, although its use should be optional depending on what the mobility management needs.  If the information in IS are concerned with higher/managerial-level information, such as operator, authentication, etc, then we should not exclude the possibility of integrated operation with other protocols such as mobility, security, etc. In this case, imposing such information exchange before mobility protocol kicks in is not a desirable scheme that design of mobility management would like to be restricted to.

    SD>  I  agree with you that .21 IS framework should not exclude the possibility of integrating with other  protocols such as mobility and security.  By the same  logic, it should not mandate the integration as
             well.  We should  define the IS  independently. Of course, we need to captute the relevant information that these protocols may need and iteract with during handover. 

 
  • By defining the information, I mean defining what a specific piece of information is (semantically) and how is it structured and encoded (syntactically).
              Agree.  Again, pl. let us know if you have any specific requirements in mind.

[hong-yon] I am thinking... But I am still struggling to understand what sort of IS information we are dealing with, as described above.
     SD>  I understand. Pl. let us know if you come up with something.


  • My thought is that different mobility management mechanism will be interested in different set of pieces of information. Thus, the way a piece of information is defined should allow easily any interested protocols to ask for and convey it in their protocol payload. Besides, as one cannot exhaustively identify all pieces of information to be defined, the way a piece of information is defined should allow easily new pieces of information to be defined in the future in a co-ordinated manner. One possibility is to have each piece of information to be defined apply for an ICANN number for the information type. There can be other ways.
            Agree with you and that's why  we want the flexibility in information definition. We can definitely go to ICANN for a information type and that should be in the basic set. We should also leave some
             flexibility  to the operators so that they can define vendor specific IEs as well.

[hong-yon] I agree.

  • As stated above, it is likely that the query/response could be embedded in a mobility management protocol, or indeed any protocol that is interested in the defined information. A typical query, as whole or part of a PDU (protocol data unit), can include one or more information type number. The response, as whole or part of a PDU, can include the information that are asked for.
              I  don't think this is a good idea. The very reason we wanted to have .21 IS so that it can work with multiple  mobility protocols will be lost. Also do you think we should suggest adding this feature
                to  'n' mobility protocols? Hope not.  

[hong-yon] As described above, it depends what sort of IS information we are dealing with. For higher/managerial-level information, I know that I may want to integrate certain information exchange in my mobility management scheme. This is an area in which the separation between mobility management and 802.21 is not black-&-white. Thus to FACILITATE mobility management, 802.21 IS should not restrict how a mobility management scheme could be established. I am suggesting that the information should be defined, but whether and how they are used should be left other protocols for flexibility. Or, if 802.21 is to specify the IS query/response messages/protocol, it shall only be optional.

   SD>  Same as above


  • I think one challenge is to identify what information need to be defined to potentially facilitate mobility management.
             It may be difficult  to  define all of them now.. That's why the basic and extended sets idea seems to be better.

[hong-yon] I agree that it is hard to list the information types now. As described above, I think we should at least decide what sort of information we will address in IS: link-level information, higher/managerial-level information, etc, so we now whether 802.21 should specify the IS query/response protocol.
     SD> There was an attempt to captute these level of details  and you may find that in Section 6 (Introduction)  in the current draft. We will fuurther modify it and address  it properly.



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