Re: M3UA and SUA recommendations
Stanislav Ivanovich <[email protected]>
| Newsgroups | gmane.ietf.sigtran |
|---|---|
| Message-ID | <[email protected]> |
Siu Chai, In addition to the last mail, here is a practical example of my point that xxUA specifications certainly do not specify any box/layer (in terms of how ITU-T does it for MTP or SCCP or TCAP...) but instead xxUA specifications are only protocol specifications: NOTIFY chapters in xxUA specifications do not define any criteria how/when/if ASP/IPSP'es (application clones) should react to received NOTIFY message reporting insufficient resources. For example an AS consists of 3 application clones ASP1, ASP2 and ASP3 which are (like in all redundancy models) synchronized by application protocols (which are out of scope of xxUA specifications). If ASP2 is inactive and ASP3 fails while only ASP1 is active and working SGP may report insufficient resources to ASP2. Who do you think should respond to this NOTIFY? Can that do some "ASP xxUA layer/box" which does not contain application logic? Typically not since application logic is the owner of this decision. Anyway with very good reasons you do not have it specified in xxUA specifications and since the decision is normally in application logic therefore the upper interface itself is not normative but informative... If like you say xxUA is layer/box which MUST contain all the xxUA concepts and logic then how would that box answer NOTIFY if the criteria for this decision (as is the typically the case) is application owned? And each application can have its own criteria (e.g. if number of mobile subscibers is >xxx and ...then react with activation otherwise ignore...). As I said -> APS/IPSP'es are application processes and any layering inside them is out-of-scope of xxUA specifications. Any references there are only informative. What is said here for NOTIFY is similar for other xxUA chapters and messages... / Stanislav Ivanovich Stanislav Ivanovich <[email protected]> wrote: Siu Chai, No, I am not questioning anything in xxUA specifications but instead pointing to the difference between normative and informative parts of them. / Stanislav Siu Chai Tho <[email protected]> wrote: Hello Stanislav, Stanislav Ivanovich <[email protected]> wrote: Layering is a architectural design pattern and thus only applicable to implementations. Nevertheless it's an important architectural choice to choose layers. [...] [Stanislav Ivanovich] Nonsense! Layering or not layering is certainly not visible on the external xxUA protocols since it is implementation matter. For example I have two M3UA ASP implementations: 1) One applies layered approach where traffic control appplication + supporting user part functions are kept intact while all the AS concepts are put within a layer called "M3UA ASP" which is managed separately. 2) In the second non-layered approach I decide to make modifications to 3 SW components of traffic control application + 2 SW components of user part functions because by looking into product manaulas, descriptions, sequence diagrams (i.e. not in xxUA specifications but instead in my implementation documents) I found that it is easier to make these modifications than to introduce a separate "M3UA ASP" layer which shall be separately controlled by its own management (commands)... However both (!) of my ASP implementations when connected to SGP behave strictly 100% in compliance with ASP-SGP protocol as defined in M3UA specification! [Siu Chai Tho] I think you are questioning the usefulness of protocol layers in specifications. I didn't wanted to broaden the discussion to that level. I was merely trying to understand if the UAs define a layer or not. So far I t! hink I received a positive answer. Thank you, Joe Send instant messages to your online friends http://au.messenger.yahoo.com _______________________________________________ Sigtran mailing list [email protected] https://www1.ietf.org/mailman/listinfo/sigtran --------------------------------- Yahoo! Autos. Looking for a sweet ride? Get pricing, reviews, & more on new and used cars._______________________________________________ Sigtran mailing list [email protected] https://www1.ietf.org/mailman/listinfo/sigtran --------------------------------- Yahoo! Photos Ring in the New Year with Photo Calendars. Add photos, events, holidays, whatever. _______________________________________________ Sigtran mailing list [email protected] https://www1.ietf.org/mailman/listinfo/sigtran