September 1998 - sg16-avd - lists.packetizer.com

Re: H.225 Annex G
by Scott Bradner 04 Sep '98

04 Sep '98

Douglas reports: One is for IP routers to route e.164 addresses in the same way as they do IP packets. In this scheme, gateway advertisements would occur via a modified IP routing protocol (BGP I think it was). yes, this idea was mentioned but the person who presented it called it "a bad idea" most people who run Internet service providers or who deal with routing protocols fully agree with that conclusion as Douglas noted the state of much of the effort is a "still-debated problem definition" Scott (Area co-director for Transport in the IETF, the area in which this work is being debated)

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RAI time-out and retry count
by Kaynam Hedayat 03 Sep '98

03 Sep '98

Hi, Looking over H.225.0 we have noticed that the recommended time-out and retry count values for RAI (ResourceAvailabilityIndication) command are not specified in the table of section 7.19. We would like to recommend a time-out value of 3 seconds and retry count of 2 (same as RRQ). Thank you. Kaynam Hedayat PictureTel Corporation

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Re: Q. about master/slave determination in H.245
by Jim Toga 03 Sep '98

03 Sep '98

My comments below.... Regards, jimt. At 12:13 PM 8/21/98 +0800, you wrote: >Hi.. > I have some questions about master/slave determination in H.245. >Perhpas these questions are stupid... but could you please kindly give me >some help? > > With H.245, we need to do master/slave determination to resolve >conflicts between two endpoints which can be the MC in a conference. > >(1) If there is no MC is active and all entities are of different types, >the priority to win the master/slave determination is MCU > Gatkeeper > >Gateway > terminal. THis means. e.g., with Gatekeeper and terminal, >Gatekeeper always wins the determination? then why bothering to >set "statusDeterminationNumber" to be a random no. in that certain range? > >or only when those entities are all in the same type, then such setting >just makes sense? i.e., "terminalType" overrules >"statusDeterminationNumber" ?? Seems like a reasonable optimization.....it has been discussed before but never documented. > >(2) An MC that is already acting as an MC shall always remian the active >MC. However, assume that there are only terminals participating in a >conference, what if a terminal that won the determination already >decides to leave the conference at some time during the call? Should we >need to perform such master/slave determination again?, or the terminal >can assign the other to be an active MC?, or the terminal by no means can >not leave the conference in the middle of the call? > If more than two terminals are in the conference then there must be an MC envolved. If the MC leaves the conference (note that this is not the same as the colocated Terminal leaving...) then the conference must end. The H.245 connections all go to the MC.... >Please advise... thanks a lot.. > >Best regards, > >Wanjiun Liao > ***************************************************** *** +1-503-264-8816(voice) Intel - Hillsboro, OR. *** *** mailto:jim.toga@intel.com mailto:james.toga@ties.itu.int *** *** PGP keyID 36 07 86 49 7D 74 DF 57 50 CB BA 32 08 9C 7C 41 *** *****************************************************

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No root node
by Pete Cordell 03 Sep '98

03 Sep '98

Dear All, Apologies for not being on the last call, but... I feel one really important issue with Santo's contribution is that we must remove the root domain. Having such a concept would give politicians and lawyers far too much work!!! I believe the notes that I put forward would allow the root node to be removed, and based on comments I heard from Jim, I believe what he is proposing would allow this too. Regards, Pete ================================= Pete Cordell BT Labs E-Mail: pete.cordell(a)bt-sys.bt.co.uk Tel: +44 1473 646436 Fax: +44 1473 645499 =================================

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Re: H.323 Addresses
by Pete Cordell 03 Sep '98

03 Sep '98

Douglas, Although billing for IP based calls is very likely to be very different from that used in the PSTN world, (and I would be prepared to bet that it was distance independent!!!), I think it is far too early to enshrine such a concept into the work we are doing. For example, an operator, possibly a start up, may want to connect a big fat intra-net style IP pipe out the back of there new local POTS point of presence and use that to inter-connect with the rest of their network. They would want to have the option of doing distance based charging so that they can shadow their competitors on pricing policy. I don't think we should dive into billing etc., but I still think we need to allow for geographically based routing. On the following the sun policy, I see this as much the same as 'basic' user mobility. I would expect this to be based around something like home and foreign gatekeeper concepts that have been posted on this list. Regards, Pete ================================= Pete Cordell BT Labs E-Mail: pete.cordell(a)bt-sys.bt.co.uk Tel: +44 1473 646436 Fax: +44 1473 645499 ================================= >---------- >From: Douglas Clowes[SMTP:dclowes@OZEMAIL.COM.AU] >Sent: 03 September 1998 02:57 >To: ITU-SG16(a)MAILBAG.INTEL.COM >Subject: Re: H.323 Addresses > >Hi All, > >It's a shame I wasn't on the call, I might find out what's going on :-( >Thanks to those who are exposing it on the list. :-) > >In my mind, address resolution (or number translation) is a multistage >process. > >In the context of the caller, a destination address may be an >"internal" >form like an abbreviated dialing number (*21), a service prefixed >number >(01161294332374), or a nickname ("doug"), that has to be translated >into an >"external" form. The result of this stage is an external address. > >Once in the external form that identifies the callee, the number is >subject >to resolution in the context of the callee. I think that 800 numbers >are >like this. Since geographical information is probably not known about >the >source or the destination, much less path metrics between them, >factoring >that into the resolution may be a problem. The result of this stage is >an >effective address. > >If the response is a prioritised sequence of endpoints, then the source >can >select from the endpoints within each priority based on >characteristics. >For example 1-800-555-1212 => (1-415-555-1212, 1-212-555-1212) and I >can >select my area code if I know it. > >The third step involves endpoint location, sometimes called gateway >location. This involves taking the effective address and locating a >physical (transport) address that can handle it. This could also be a >prioritised sequence of endpoints (gateways), for each effective >address. >The source can then select from the endpoints within each priority >based on >characteristics. I might look in my IP routing tables, ping them or use >RSVP. > >I don't think that "geographical" proximity is the *real* determining >factor here. It doesn't matter if the source is sitting on top of the >destination if the link is a 300 baud serial line. > >I think that the problem being canvased here is one that comes from the >PSTN domain where the 800 charges are distance dependent. I don't think >that it translates directly to the packet network domain, where charges >are >often distance independent. > >What's more likely to be interesting, is the moving call centre where >the >effective address follows the sun from London to San Francisco to >Sydney to >maximise daytime staff utilisation. Here your 1-800 number will >translate >to 44-171, 1-415, and 61-2 depending on the time of day. > >Regards, > >Douglas > >At 18:01 02/09/98 +0100, Chris wrote: >>All, >> >>Good point, Pete! It's a shame you weren't on the call (there was a >>certain amount of guesswork as to how 800 numbers work)! >> >>There are two ways of handling this that I can see immediately. Although >>philosophically different, in practice they will normally amount to the >>same thing: >>1. The "owner" of a domain needs to be told where a query originates, >>given that the calling location may affect the answer it gives or: >>2. A border element handling queries for 800-type numbers needs to know >>what to do with it depending on the origin of the query. >> >>Regards, >>Chris >>---------------------------------------- >>Dr Chris Purvis - Senior Development Engineer, WAVE CC Software >>Madge Networks Ltd, Wexham Springs, Framewood Road, Wexham, Berks. >>Phone:+44 1753 661359 email: cpurvis(a)madge.com >> >>-------------------------------- >>Dear All, >> >>It may not be possible to handle 800 numbers in the same way as other >>numbers as the destination may be based on the geographical location of >>the caller. For example, ISPs may be accessible by something like an >>800 number which may be fixed for a whole country, but the POP you end >>up connected to may vary depending on where you called from. >> >>I'm not sure what the implications of this are, but it is something to >>think about!!! >> >>Regards, >> >>Pete >>================================= >>Pete Cordell >>BT Labs >>E-Mail: pete.cordell(a)bt-sys.bt.co.uk >>Tel: +44 1473 646436 >>Fax: +44 1473 645499 >>================================= >> >> >>>---------- >>>From: Chris Purvis WVdevmt-WS[SMTP:cpurvis@MADGE.COM] >>>Sent: 02 September 1998 13:09 >>>To: ITU-SG16(a)MAILBAG.INTEL.COM >>>Subject: Re: H.323 Addresses >>> >>>Radhika, >>> >>>>We are discussing about H.323 addresing schemes in our bi-weekly H.323 >>>>inter-GK conf calls. >>>> >>>>The H.323 addresses that are being considered are 1. E.164, 2. E-mail, >>>3. >>>>URL, and 4. TCP/UDP/RTP port addresses (and 5. aliases as well I >>guess). >>>> >>>>Although a hierarchical notion of addressing scehmes have been >>>discussed, we >>>>have also recognized that some other variations of addressing schemes >>>are >>>>there. >>>> >>>>For example, people change their physical locations, but they might >>have >>>to >>>>keep the same E.164 addresses. So, a translation is needed. Therefore, >>>the >>>>very physical relationship of E.164 addressing scheme (e.g., knowing >>>NPAs >>>>and NXXs, one can find the distance) has been broken. >>> >>>I was under the impression that finally (after several weeks of >>>discussion) we'd reached closure on this in last Thursday's call. The >>>solution that I understood had been agreed came in two parts: >>>1. Mobile IP solves most of the problem for us - E.164 number resolves >>>to >>>an IP address which may be anywhere in the world at any given moment in >>>time. >>>2. If a user wants to move (and take their number with them) to being >>>in >>>an administrative domain with an otherwise reasonably contiguous E.164 >>>address space, this is easily handled as follows. The domain that >>>"should" (in the hierarchical sense) "own" the number that the user is >>>keeping holds a record of where to contact the current holder of that >>>number (which will typically be an entity to which an LRQ message can >>>be >>>sent). >>> >>>>Another example can be 800 numbers where the translation is also >>needed. >>>It seemed to be agreed in the call that 800 numbers are not a special >>>case, but merely an example of number portability. >>> >>>>In addition, from mobility point of view (device or person) wired (and >>>>wireless?) environement may also be looked into. >>>Does this mean anything at all? >>> >>>>As we go froward, we may consider many of those aspects as pointed >>above >>>to >>>>provide solutions for the H.323 addressing schemes. >>>I was under the impression that we'd reached closure on most of these >>>already. >>> >>>Regards >>>Chris >>>---------------------------------------- >>>Dr Chris Purvis - Senior Development Engineer, WAVE CC Software >>>Madge Networks Ltd, Wexham Springs, Framewood Road, Wexham, Berks. >>>Phone:+44 1753 661359 email: cpurvis(a)madge.com >>> >> >> >

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Three TDs have been uploaded
by Sakae OKUBO 03 Sep '98

03 Sep '98

Dear Q.12-14/16 experts, I have placed the following three TDs for the coming SG16 meeting at the Incoming directory (ftp://standard.pictel.com/avc-site/Incoming/): H220AM6.zip - Amendment 6 to H.222.0 for Determination Q12status.zip - Q.12/16 status report Interim.zip - Report of interim Q.12-14/16 meetings They were all produced with Word 98 Mac (compatible with Word 97). Best regards, Sakae OKUBO (Mr.) *********************************************************** Waseda Research Center Telecommunications Advancement Organization of Japan (TAO) 5th Floor, Nishi-Waseda Bldg. 1-21-1 Nishi-Waseda, Shinjuku-ku, Tokyo 169-0051 Japan Tel: +81 3 5286 3830 Fax: +81 3 5287 7287 e-mail: okubo(a)giti.or.jp ***********************************************************

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Re: H.323 Addresses
by Chris Purvis WVdevmt-WS 03 Sep '98

03 Sep '98

All, Good point, Pete! It's a shame you weren't on the call (there was a certain amount of guesswork as to how 800 numbers work)! There are two ways of handling this that I can see immediately. Although philosophically different, in practice they will normally amount to the same thing: 1. The "owner" of a domain needs to be told where a query originates, given that the calling location may affect the answer it gives or: 2. A border element handling queries for 800-type numbers needs to know what to do with it depending on the origin of the query. Regards, Chris ---------------------------------------- Dr Chris Purvis - Senior Development Engineer, WAVE CC Software Madge Networks Ltd, Wexham Springs, Framewood Road, Wexham, Berks. Phone:+44 1753 661359 email: cpurvis(a)madge.com -------------------------------- Dear All, It may not be possible to handle 800 numbers in the same way as other numbers as the destination may be based on the geographical location of the caller. For example, ISPs may be accessible by something like an 800 number which may be fixed for a whole country, but the POP you end up connected to may vary depending on where you called from. I'm not sure what the implications of this are, but it is something to think about!!! Regards, Pete ================================= Pete Cordell BT Labs E-Mail: pete.cordell(a)bt-sys.bt.co.uk Tel: +44 1473 646436 Fax: +44 1473 645499 ================================= >---------- >From: Chris Purvis WVdevmt-WS[SMTP:cpurvis@MADGE.COM] >Sent: 02 September 1998 13:09 >To: ITU-SG16(a)MAILBAG.INTEL.COM >Subject: Re: H.323 Addresses > >Radhika, > >>We are discussing about H.323 addresing schemes in our bi-weekly H.323 >>inter-GK conf calls. >> >>The H.323 addresses that are being considered are 1. E.164, 2. E-mail, >3. >>URL, and 4. TCP/UDP/RTP port addresses (and 5. aliases as well I guess). >> >>Although a hierarchical notion of addressing scehmes have been >discussed, we >>have also recognized that some other variations of addressing schemes >are >>there. >> >>For example, people change their physical locations, but they might have >to >>keep the same E.164 addresses. So, a translation is needed. Therefore, >the >>very physical relationship of E.164 addressing scheme (e.g., knowing >NPAs >>and NXXs, one can find the distance) has been broken. > >I was under the impression that finally (after several weeks of >discussion) we'd reached closure on this in last Thursday's call. The >solution that I understood had been agreed came in two parts: >1. Mobile IP solves most of the problem for us - E.164 number resolves >to >an IP address which may be anywhere in the world at any given moment in >time. >2. If a user wants to move (and take their number with them) to being >in >an administrative domain with an otherwise reasonably contiguous E.164 >address space, this is easily handled as follows. The domain that >"should" (in the hierarchical sense) "own" the number that the user is >keeping holds a record of where to contact the current holder of that >number (which will typically be an entity to which an LRQ message can >be >sent). > >>Another example can be 800 numbers where the translation is also needed. >It seemed to be agreed in the call that 800 numbers are not a special >case, but merely an example of number portability. > >>In addition, from mobility point of view (device or person) wired (and >>wireless?) environement may also be looked into. >Does this mean anything at all? > >>As we go froward, we may consider many of those aspects as pointed above >to >>provide solutions for the H.323 addressing schemes. >I was under the impression that we'd reached closure on most of these >already. > >Regards >Chris >---------------------------------------- >Dr Chris Purvis - Senior Development Engineer, WAVE CC Software >Madge Networks Ltd, Wexham Springs, Framewood Road, Wexham, Berks. >Phone:+44 1753 661359 email: cpurvis(a)madge.com >

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Re: Communications between Administrative Domains
by Andrew Draper WVdevmt-WS 03 Sep '98

03 Sep '98

On Wed, 2 Sep 1998 10:37:32 +1000 Douglas Clowes wrote: > From my POV, this underscores the need for thought on the Back End > Services, both in terms of the services to be offered, and the protocol(s) > to support those services. Just for my information, where does the term Back End Services come from? Is this related to some sort of protocol currently run by telcos (SS7 database services for example)? Does the term always refer to a third server somewhere else which communicates with both the originating and destination border elements? While discussing billing, I assume that we are only discussing payment from the originating administrative domain to the destination administrative domain and that we are not discussing payment to the transport network providers (such as ISPs) for QoS connections (such as those set up by RSVP). > Here, it is fairly clear that authentication and billing is a Back End > Service. The available destinations for a call may be dependent on the > (authenticated) identity of the caller. Yes, I agree that some entities will reject SETUP messages which are not authenticated and do not provide a suitable payment token. However, I think we should try hard to design a protocol which will not cause hopeless (bound to fail) SETUP messages to be sent. This is important because a) SETUP messages create state in the recipient and b) SETUP messages may involve charges to the originating administrative domain. Later on in this message I use the term "setup requirements" to refer to a description of setup messages which the destination administrative domain will accept. Examples would be "you must authenticate using mechanism X (and server Y)" or "you must pay using method Z" (are there any other forms of setup requirement?). I use the term "setup capabilities" to refer to the set of mechanisms which the originating border element is able to send in a SETUP message (because they have been implemented and enabled). > The "token" to be included in the > Setup message is produced by the Back End Service and may well be > destination sensitive. I agree. > Which raises the possibility of address translation > also being a back end service. In the sense of having a third party server (not belonging to the originating or destination administrative domain) perform address translation I agree. > Back-End Services (may) include: > > o caller identification, authentication, and authorisation; > o address translation, gateway location; > o call pricing; > o call detail recording, billing, and settlement; By my understanding of the term back-end services (which might be wrong) call pricing is for the destination administrative domain and is unrelated to any third party server. Call detail recording is also a problem only for the destination administrative domain. > which are all interrelated Out of interest, are you expecting/requiring that the services provided by each of your bullet points must be provided by the same third party server (or would using one server for address translation and another for billing be acceptable). If not then how are they all interrelated? > and, in total, outside the scope of the > gatekeeper to gatekeeper communications. I disagree. Here are my reasons for thinking that identifying the requirements of the destination administrative domain fall within the scope of communications between administrative domains (an important subset of gatekeeper-gatekeeper communications). To prevent hopeless SETUP messages from being sent the originating border element (or a third party) needs to work out the intersection of its setup capabilities and the destination border element's setup requirements. As far as I can tell there are three ways for the originating BE to find out the destination administration domain's setup requirements: a) It can find out during the resolution stage (the stage where an email-ID or E.164 number is translated to the address of a border element). b) It can find out during the LRQ/LCF exchange. c) We could design an extra protocol which is used before/after LRQ/LCF to let the originating BE find out what the requirements of the destination BE are. For an email-ID type destinationAddress using the DNS to find the destination border element seems non-controversial. DNS only provides the name and address of the destination, so method a is not appropriate. In this case I favour method b over method c for two reasons: firstly because it reduces the number of round trips required for a call setup and secondly because requirement 7 (of the latest annex G draft "diff0201.doc") suggests that the minimum number of changes to existing protocols should be made. The E.164 to border element address protocol is as yet unspecified, so it could return the requirements of the destination administrative domain at the same time as it returns the address to which to send LRQ. If the E.164 number resolves to an administrative domain which can be contacted directly then this doesn't seem to help much (as only one address is provided to which an LRQ must be sent anyway - so there are no efficiency savings to be made). If the E.164 number would resolve to one or more third party gateways (eg. for a POTS number) then passing the setup capabilities of the originating border element might help narrow down the responses which the resolution server returns. However this has security implications and so should be a choice for the originating BE. We still need a mechanism for the originating BE to ask the destination BE about its setup requirements if it is being paranoid and not telling the resolution server. Hope this makes sense (and my assumptions aren't too wildly different from yours). Regards, Andy. -- Andrew Draper - Principal Development Engineer - WAVE Software Madge Networks, Wexham Springs, Framewood Road, Wexham, Berks. mailto:adraper@dev.madge.com phone:+44 1753 661329 pgp fingerprint D6 ED 72 4F 96 BB CA 2D 68 74 4C E0 CB B9 0B 3F

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Directory Services?
by William Pimentel 02 Sep '98

02 Sep '98

Hi all I haven't seen anything about directory services interacting with GKs, how would a user know the alias (number or string) of the other party he/she wants to call? Or is there any way for a Terminal user to retrive/search the users currently registered with a GK? And what if the other party is register with another GK? Thanks -- William Pimentel w-piment(a)uniandes.edu.co

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subscribe, how to
by Barnaby Duncan 02 Sep '98

02 Sep '98

I wish to subscribe to this list. Please infrom me of the way to do that. Barnaby

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