Hi, Ed and All: I do not know whether you have seen my reply to Jaakko. I am enclosing it again. Please respond to my reply to provided Jaakko to prove your statement. I completely disagree with Ed. Please also see Marc Roelands's comments on LA. AT&T contribution has shown how H.323 mobility problem can be solved using home/foreign GK (zone). I like to see the complete H.323 mobility problem that has been solved using the alternative approach as proposed by Nokia. I have NOT seen Nokia's solution yet. Unless a complete solution is provided like AT&T's, I am NOT convinced how mobility problem can be solved in a better way. I also see that there is a need for HLF/VLF. No one against the HLF/VLF function. AT&T proposal also has shown how HLF/VLF function is taken care-of. What I disagree with is this: A protocol should NOT be implementation specific. For example, we do have a luxury to build one protocol for distributive GK (HLF/VLF) function, one protocol for centralized GK (HLF/VLF) function or one protocol for hybrid GK (HLF/HLF) function. It is against the fundamental concept of H.323. For example, the same argument can also be applied for the directory function. Similar may the case for other functions as well. It is a complete break down of H.323 protocol and architecture. So, HLF/VLF is another function in H.323. HLF/VLF is NOT a "Holy Grail" for which we have to create a complete "DISCONTINUITY" in existing H.323 protocol and architecture. I like see to Nokia's alternate solution to disprove this fear. Nokia has to bring a complete contribution providing solution like AT&T's to prove their case. Otherwise, we cannot proceed with a concept that has not proved with a solution. The problem can be solved as follows: 1. Let Nokia provide a complete proposal solving the H.323 mobility problem using heir alternative approach. What Nokia has provided is a high level concept. They have NOT solved the problem yet. Let us see what the complete solution is. If a solution is provided, we can then compare Nokia's solution with that of AT&T's solution. Otherwise, their proposal is still HYPOTHETICAL. It is a concept, NOT a solution. 2. How can we agree on a concept without seeing its solution that has the potential to break down the fundamental architecture of existing H.323 standard? 3. Let us solve H.323 mobility problem within the framework of H.323. 4. Let us move on with contributions for the part that we can agree on. If Nokia brings a complete solution, we will definitely re-consider their case. 5. I agree with you that we also need to work for interworking between H.323 (IP) mobility and cellular-PSTN/ISDN network. Finally, Ed - you have made a statement, but it has to be proved providing a solution. An alternative concept is there, but we have not seen its solution yet. What is the problem to bring the alternate solution? Why do we need to wait for a concept that has NOT been substantiated with a solution yet? Best regards, Radhika

-----Original Message----- From: Edgar Martinez [1] [SMTP:martinze@CIG.MOT.COM] Sent: Thursday, November 04, 1999 9:47 AM To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: H323mobility: Summary of discussion Importance: High

I agreed with most of Jaakko comments and also make vaild points, and will like to add the following.

I believe that the (Home) in Home Zone should be taken out. What we are talking about is the User's Point of Attached in any given Zone. The HLF is ready and Data base which has the User's profile and the current user's location. We can get a new name to HLF and call it the Location Profile Register (LPR) or Location Profile Function (LPF).

I also believe that the (Visited) in Visited Zone sould also be taken out because again we are talking about the Users current Point of Attachment in any given Zone. The VLF has the means to update the Location Profile Register (LPR) from any given Zone. We can get a new name to VLF call it the Location Update Register (LUR) or Location Update Function (LUF).

Now we can also support concepts of Zone ID's such as Current Zone ID and Previous Zone ID.

Finally,

And I strongly agree with looking at the interworking in parallel with H.323 mobility. The time we spent now looking at interworking will be compensated in the long run. I sure does working on ISUP, IN and Qsig, inetrworking with H.323 would agree and we should learn from their experience. And not leave it for a last minute add-on.

Lets take the contribution as they come, if one wants to put in interworking fine. If one wants to put in contributions only H.323 mobility also fine. Both are in order and within our scope.

The general strategy should focus on ensuring that the H.323 Mobility and interworking options are enabled, rather than spending too much effort blocking alternative options (Our limited resources frankly don't allow this luxury). But there really is no substitute for doing the work - preparing input papers and presenting them to move things forward.

Best Regards,

Ed [Roy, Radhika R] Hi, Jaakko:

Pl. see my reply provided below. Best regards, Radhika -----Original Message----- From: jaakko.sundquist@NOKIA.COM [SMTP:jaakko.sundquist@NOKIA.COM] Sent: Tuesday, November 02, 1999 11:13 AM To: ITU-SG16@MAILBAG.INTEL.COM Subject: Re: H323mobility: meeting Once again, hi, Radhika, Ed + all See my comments below... Hi, Jaakko, Ed, and All: I hope that Jaakko will get this mail while he is in his office (Thanks Jaakko - you have reminded us the time difference)! [Jaakko:] You caught me just in time. Please note the following: 1. Zone and domain are well defined in H.323. [Jaakko:] Yes, they are defined. 2. We have to work for mobility solution in a way that fits very well that already exists in H.323. [Jaakko:] Agreed. 3. We can invent many things if we need to solve mobility problems only when we think that those functions are NOT covered in existing H.323 standard. [Jaakko:] Yes. 4. If mobility problems can be solved using the concept of "zones" and "domains," I would assume that it would be a big mile stone so far the continuity of H.323 is concerned. That is, as Ed pointed out, H.323 mobility problem is NOT a rocket science. We have to remember that we are working in the framework of already existing H.323 standard architecture. We have to relate our solution in the context of existing H.323 standard. In other words, we CANNOT change the fundamental concept of existing H.323 standards just because we are addressing mobility. [Jaakko:] Yes, of course. I'm not arguing against that. I guess you are referring to the Location Area discussion here. The LA concept is really merely a scaling issue, you could of course handle paging (I'm assuming that we will need the paging procedure) based on zones, i.e. page every NPoA in a zone when a call arrives, but this might be quite limiting in some cases (the zone may be needlessly big or very small). I do not think that we need to change any fundamental concepts of H.323, if we introduce the LA concept. [Roy, Radhika R] May be we can include LA when we see that we need to optimize a zone further. We may revisit this in the second step. 5. I do not understand what benefits we are gaining adding more "terminologies" like "AREA {home, foreign, etc}" while the "zone" and "domain" are already well defined in H.323. My personal view is that we should FIRST try to solve H.323 mobility problems within the context of "zone" and "domain" as far as practicable. I would argue that zone and domain are good enough to serve this purpose for now. (Pl. also see AT&T's and Motorola's contributions.) [Jaakko:] As I already said, I did not intent to define the terms: home area and visited area. I was just trying to illustrate the point I was making about not having the Home/visited zone terms defined yet. [Roy, Radhika R] It is good point. Let us define these. AT&T contributions have the detail definition for each term. 6. With respect to your comments that it appears that every GK will have HLF and VLF function, I would say that every GK will have the access to the HLF and VLF function. This capability for each GK has to be provided because of the fact that H.323 architecture is GK-centric. We do not have any choice because we are restricted by the H.323 architecture. [Jaakko:] I did not argue against this. The point is that if we identify a concept called the Home Zone, this already implies that each User has only one zone, in which he/she/it is not a "visiting user". I think this would be really restricting. [Roy, Radhika R] As I mentioned that H.323 is the GK-centric. A user may change his/her network point of point attachment, but it is still the same (Home) GK. So, a given (home) GK, there has to be another level of granularity to address mobility in terms of network point of attachment. Please see AT&T contribution how home and foreign network concept have solved the problem. Similar is the case with Motorola's contribution. The bottom line is that home/foreign GK concept does NOT imply any restriction to solve H.323 mobility. 6.1 With respect to your question whether HLF/VLF can be distributive or centralized, having said (in item 5) that every GK should have access to HLF and VLF function, it is up to implementation whether HLF and VLF function can be centralized or distributive. Please see AT&T contributions submitted in Red Bank how we can implement these functions in both distributive and centralized environment. [Jaakko:] This is actually quite much the point I was making. By defining the Home Zone we would in my mind actually be pointing to the centralized model. [Roy, Radhika R] By definition, there can as many GKs as one wish have in an H.323 system. So, by definition, the GK-centric H.323 architecture is distributive. By defining home/foreign GK, H.323 mobility also becomes distributive up to the point that a basic H.323 system allows us. So, we do not see any limitations. 6.2 In an analogy of this HLF/VLF function, I can bring another function - Directory services. For example, H.323 assumes that all the address (e.g., alias, transport, network) are kept by each GK. H.323 does not answer how the address information is maintained by each GK. People are using LDAP directory server. The question is: whether that directory service is distributive or centralized? I guess that it can be done in both ways depending on implementation. [Jaakko:] My point exactly. I would like that all GKs inside the same Administrative Domain would be able to access the same HLF/VLF functionality. [Roy, Radhika R] As I pointed out, this an implementation issue. I would argue that we should allow both options and let an implementor choose as it is necessary. Please also see AT&T contributions how both options can be addressed. 6.3 In AT&T contribution, it is shown that it better to make VLF distributive (per GK) although HLF function can be made both distributive and centralized. Again, this is a matter of implementation. As mentioned in AT&T contribution, we also need to define a kind of backend protocol for VLF and HLF (something like similar to Siemens, Nokia and Intel's contribution - TD-39: Security Services for Backend Services and Mobility in H.323). [Jaakko:] I would assume that you can distribute the HLF/VLF functionalities inside the Administrative Domain as you like, but distributing them between the Domains would be difficult. Actually I think that the concept of Administrative Domain was introduced in H.323 for this kind of reasons. [Roy, Radhika R] Again, H.323 system is GK-centric in a given domain. For inter-domain, it is BE-centric. In a given domain, H.323 architecture has to be GK-centric. Once we solve intra-zone and inter-zone (intra-domain) mobility, we can extend our experience for inter-domain problem as well. Please also see AT&T contribution how these problems have been addressed. My replies to 6.1 and 6.2 are also good for this case. 7. Again, I, personally, do not rule our to re-examine the benfit of "AREA" (e.g. location area [LA]) vs. "ZONE/DOMAIN" concept. May be it is in the second step. [Jaakko:] I am just a bit afraid that if we leave this kind of a major mobility related concept out of the first phase thinking process, we will find it much more difficult to include the concept in the second phase (where I think we will need it). Furthermore, I'm not convinced that the LA concept would not be useful in the pure H.323 approach either. [Roy, Radhika R] I think that it can be place holder for now. I would request to bring more detail contributions proposing solutions like AT&T and Motorola to prove the case better. Then, we can compare both solutions. In AT&T contribution, I feel that the LA can be accommodated to optimize the zone further. So, I do not see that it is a problem to accommodate the LA concept if needed. I personally prefer that we can better address this in the second phase once we solve the problem for the basic architecture. Hope that this email will clarify the things better. [Jaakko:] I think the main thing is that we got the discussion going on again. I'm kind of tired already, and I hope that I didn't mess things up too much in this mail. [Roy, Radhika R] Definitely, I also like that discussions must go on. We must be convinced that we have the best solution because it has the severe implications for all on-going mobility standard works throughout the world once we standardize H.323 mobility in SG16. Best regards, Radhika Same to you, Jaakko

-- Edgar Martinez - Principal Staff Engineer Email mailto:martinze@cig.mot.com FAX 1-847-632-3145 - - Voice 1-847-632-5278 1501 West Shure Drive, Arlington Hgts. IL 60004 Public: TIPHON & Other Stds - http://people.itu.int/~emartine/ Private:TIPHON & Other Stds - http://www.cig.mot.com/~martinze/