Subject: AW: AW: [Iptel] FW: [Enum] Summary on NoPSTN dicussion

From: "Stastny Richard" <[email-masked]>
Date: Fri, 02 Apr 2004 03:38:19 -0500

Jim wrote:

	If the E.164 number has been assigned to a SP providing a PATS, then the PSTN will (must - because of opt-in) always know how to route to the appropriate SP, and the SP in turn knows how to route to the device. If the number is an ENUM only number, then the PSTN will need to know this (both the fact that it is a valid number so it does not reject it, and the fact that it is an ENUM-only number so that it can route it to an ENUM enabled GW). The PSTN will be able to determine this using existing routing & translation techniques - nothing more is required.

	So the entire problem comes down to how the VoIP network can recognize that a number is an "ENUM-only" number, and not route this to the PSTN if there is no ENUM entry. For all other cases routing to the PSTN works fine. This means that whatever solution we come up with, it is only necessary to apply it to ENUM-only numbers. (We *may* decide it is valuable to also apply it to other numbers, but if it complicates things this is not necessary.)

	Am I missing something? 

	>Richard:
	No, this is the prime requirement, all other things are nice to have. On the
	other hand, if we find a solution which is also automatically solving the
	other niceties, we caould use it for this also. I will try to sum up the proposed
	solutions next week, so we can decide on the best way forward.
	
	I talked to Rich Shockey today and the plan is to have a principal idea
	within the next weeks to have this written down for San Diego in time.

	Richard

	Jim 

	-----Original Message----- 
	From: Michael Hammer [mailto:[email-masked]] 
	Sent: Thursday, April 01, 2004 3:58 PM 
	To: Pfautz, Penn L, ALABS 
	Cc: Stastny Richard; McEachern, James [CAR:5N00:EXCH]; [email-masked] 
	Subject: RE: AW: [Iptel] FW: [Enum] Summary on NoPSTN dicussion 

	This sounds reasonable to me, but I would rather hear from the DNS experts. 

	My assumption, as you note below, was that if the number was not in ENUM, 
	then the only element that knows whether the number is assigned and 
	reachable is the operator PSTN-IP GW that has a configured translation or 
	knows that the number is unassigned. 

	Mike 

	At 12:11 PM 4/1/2004 -0500, Pfautz, Penn L, ALABS wrote: 
	>If I understand it the root issue is this: 
	>All E.164 numbers will have a PSTN point-of-interface, but for some 
	>numbers that POI is a gateway to IP. Further some subset of these numbers 
	>are ones that won't be assigned if they're not reachable through IP. So, 
	>in order to avoid routing to the default gateway after an ENUM query that 
	>returns no result because the number is unassigned, people are seeking 
	>some mechanism to provide a response to the initial ENUM query to indicate 
	>that attempts to route through the PSTN will be fuitless. And the need is 
	>to do this without treading on the opt-in principle. 
	> 
	>Here's a thought which the more DNS/DDDS literate may be able to confirm 
	>or shoot down: 
	>At Tier 1, instead of populating an NS record with the tier 2 delegation 
	>for each number instead populate a pair of non-terminal NAPTR records with 
	>different service fields (e.g.,  E2U  and E2C) which would point to the 
	>domains for the end user Tier 2 and carrier Tier 2 respectively. In this 
	>way, a single query would provide pointers into both trees and a client 
	>could decide whether to pursue one or the other, or potentially both. For 
	>non-assigned "ENUM-only" numbers, the carrier could populate the E2C 
	>record only without treading on the perogatives of the end user or having 
	>to instantiate a separate Tier 1. 
	>Such E2C records could not only address the NoPSTN issue but also be the 
	>basis for a carrier or infrastructure ENUM capability that may become more 
	>important as VoIP moves beyond arbitrage to where IP interconnection 
	>becomes norm. 
	> 
	>Penn Pfautz 
	> 
	> 
	>-----Original Message----- 
	>From: [email-masked] [mailto:[email-masked]]On Behalf Of 
	>Stastny Richard 
	>Sent: Thursday, April 01, 2004 2:36 AM 
	>To: Michael Hammer 
	>Cc: James McEachern; [email-masked] 
	>Subject: AW: AW: [Iptel] FW: [Enum] Summary on NoPSTN dicussion 
	> 
	> 
	>Mike wrote: 
	> 
	>         >>First, no number is owner by anybody, it is assigned by ITU-T 
	> to the NRA, 
	>         >>and assigned in turn to the SP, and the SP assignes it to the 
	> end-user (for 
	>         >>geographic numbers. Service numbers are already assigned one-by-one 
	>         >>to the end-user by the NRA, no blocks, no anchor SP. 
	> 
	>         >How does this work for numbers that were assigned to an SP, that 
	> used to be 
	>         >TDM-only, but then (over time) converts to an IP-only 
	> network?  The SPs are 
	>         >very guarded about the E.164 numbers assigned to them.  That is 
	> what I 
	>         >meant by "owned."  You are suggesting that when a person with a 
	> phone 
	>         >number assigned by an SP moves to an IP-based "phone" that the 
	> SP will 
	>         >relinquish that phone number back to the NRA?  Or are you saying 
	> that 
	>         >number portability doesn't work between TDM and IP worlds? 
	> 
	>         We are talking here about four different things here: 
	>         Case 1:  a VoIP provider is also an ILEC (eg a cable operator) 
	> and gets a 
	>         number (geographic) range (block) assigned and assignes them to 
	> his users. 
	>         Since number assignement is technology independent, there is no 
	> problem here, 
	>         as long as the SP is providing a telephony service as usual (we 
	> call this PATS - 
	>         Publicly Available Telephony Service in Europe). 
	>         Note: some VoIP SP hide between small ILECs and get such number 
	> ranges 
	>         via them (e.g Vonage, sipgate.de, ...) 
	> 
	>         Case 2: Since all normal rules apply, also LNP applies, so users 
	> may port 
	>         their numbers back and forth between PSTN and VoIP SP 
	> 
	>         Case 3: The regulator reserves a special number range for VoIP 
	> (050 in 
	>         Japan, 05x in UK, 032 in Germany). If these services are declared 
	> non-PATS 
	>         NP does not apply (this is under discussion). In Japan there is 
	> also a lighter 
	>         regime regarding QoS. Regulations differ here in all countries. 
	>         In this case the VoIP SP also get blocks of numbers and route 
	> them to their GW. 
	>         I know, in the US there is no such number range. The problem I 
	> have with 
	>         such an approach is that there are differnt rules in every 
	> country and end-users 
	>         get restricted services. (e.g no NP, no access to emergence 
	> services, etc. 
	>         IMHO this will cause problems in the future 
	> 
	>         Case 4. the regulator reserves a special number range for 
	> ENUM-only routed 
	>         numbers. This should be done directly to the end-user. The 
	> advantage is 
	>         that you have NP built-in, without having to deal with normal LNP 
	> issues and 
	>         technology, saving the SP much effort. 
	> 
	>         The difference between case 3 and 4 is that in case 3 no rules 
	> exist for NP and 
	>         interconnect on IP, so you create VoIP Island that are 
	> interconnected only via 
	>         the PSTN per default. If you interconnect on IP, you can do this 
	> only currently 
	>         with bilateral agreements. In case 4 you have automatically NP 
	> and also interconnect 
	>         because you can use ENUM also on IP to interconnect. This is BTW 
	> also drafted 
	>         in the SIP Forum Service Provider WG Interconnect Consensus. 
	> 
	>         >>With ENUM-only numbers there is no need to assign blocks of 
	> numbers. 
	>         >>An ENUM-only number is the equivalent of a domain name. It is 
	> assigned 
	>         >>to the end-user directly, who chooses the SP, like with a 
	> service number. 
	>         >>You also do not assign domain names in blocks. 
	> 
	>         >I think there is an issue here.  If the SPs hold most of the 
	> current NPA 
	>         >blocks, and there is a migration of many users from TDM to IP, 
	> then do you 
	>         >lengthen the number to 11 digits to get more, or do the SPs have to 
	>         >relinquish numbers? 
	> 
	>         This a typical NANP problem. In the NANP there is only geographic 
	> area 
	>         codes (with the exception of 800 numbers). In most other country 
	> there are 
	>         more number types: you have geographic and non-geographic numbers. 
	> 
	>         Non-geo numbers are eg mobile numbers, personal numbers, etc. The 
	> advantage 
	>         here is that you relieve the pressure on the number exhaust here. 
	> Since geo 
	>         numbers are given away in blocks, you have a lot of unused numbers. 
	>         Eg in Austria the geo numbers are using up a great chunk of the 
	> numbers: 
	>         we have 1100 4-digit area codes used be appox 4 Mio subscribers, 
	>         on the other hand, we have 5 (five) 3-digit mobile number ranges 
	>         used by 4,5 Mio subscribers (80% of them are behind 2 mobile 
	> "area" codes). 
	> 
	>         The reason is simple: the mobile number ranges are flat. So if we 
	> give eg 
	>         one 3-digit number range to ENUM, we can instantly use them with 
	>         additional 7-digits for 9.999.999 subscribers. 
	> 
	>         regards 
	> 
	>         Richard 
	> 
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---

From: Michael Hammer <[email-masked]>
Date: Fri, 02 Apr 2004 12:19:01 -0500

Don't expect the PSTN to be reprogrammed to know it is an ENUM only 
number.  The switches will simply be configured to route to a particular GW 
because that is the "home switch" for that number.  If a number originally 
belonged to a TDM switch and gets ported to the GW, then the NP database 
will indicate that.  Beyond that don't expect much.

Once the call is directed to that GW, it has two possibilities:
1) it has configured information about that number,
2) it can do an ENUM look up.
Lacking both, that call gets released.

If you have an ENUM-only number, then the GW needs to know which GW that 
number is homed to, and preferably route within the IP domain to that 
GW.  This is where the carrier ENUM entry would help.

If this ENUM-only belongs to a user (and not associated with a carrier?), I 
hope they have an entry in ENUM.  What does it mean to have an ENUM-only 
number and to not opt-in?  Either there is a GW with configuration 
information to do the further routing, or the call dies, i.e., is 
unreachable except for folks that know your IP address.  But then why have 
a E.164 number at all?  So, if you have an E.164 number assigned, you must 
have an ENUM entry, either pointing directly to your IP addresses, or to a 
carrier GW that can act on your behalf.

Mike

At 04:32 AM 4/2/2004 +0200, Stastny Richard wrote:
Jim wrote:

        If the E.164 number has been assigned to a SP providing a PATS, 
then the PSTN will (must - because of opt-in) always know how to route to 
the appropriate SP, and the SP in turn knows how to route to the device. 
If the number is an ENUM only number, then the PSTN will need to know 
this (both the fact that it is a valid number so it does not reject it, 
and the fact that it is an ENUM-only number so that it can route it to an 
ENUM enabled GW). The PSTN will be able to determine this using existing 
routing & translation techniques - nothing more is required.

        So the entire problem comes down to how the VoIP network can 
recognize that a number is an "ENUM-only" number, and not route this to 
the PSTN if there is no ENUM entry. For all other cases routing to the 
PSTN works fine. This means that whatever solution we come up with, it is 
only necessary to apply it to ENUM-only numbers. (We *may* decide it is 
valuable to also apply it to other numbers, but if it complicates things 
this is not necessary.)

        Am I missing something?

        >Richard:
        No, this is the prime requirement, all other things are nice to 
have. On the
        other hand, if we find a solution which is also automatically 
solving the
        other niceties, we caould use it for this also. I will try to sum 
up the proposed
        solutions next week, so we can decide on the best way forward.

        I talked to Rich Shockey today and the plan is to have a 
principal idea
        within the next weeks to have this written down for San Diego in 
time.

        Richard

        Jim

        -----Original Message-----
        From: Michael Hammer [mailto:[email-masked]]
        Sent: Thursday, April 01, 2004 3:58 PM
        To: Pfautz, Penn L, ALABS
        Cc: Stastny Richard; McEachern, James [CAR:5N00:EXCH]; [email-masked]
        Subject: RE: AW: [Iptel] FW: [Enum] Summary on NoPSTN dicussion

        This sounds reasonable to me, but I would rather hear from the 
DNS experts.

        My assumption, as you note below, was that if the number was not 
in ENUM,
        then the only element that knows whether the number is assigned and
        reachable is the operator PSTN-IP GW that has a configured 
translation or
        knows that the number is unassigned.

        Mike

        >         additional 7-digits for 9.999.999 subscribers.

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