Issues with toll free numbers

[jack]

Recently I found that I could not dial toll free numbers in The Netherlands (for example +31-800-0429). Voxalot does an ENUM lookup for this number and e164.org returns sip:318000429@selfnet.at. But the call failed. I got an error "503 Service Unavailable", "No route to destination".

It turns out that e164.org routes every toll free number in The Netherlands to selfnet.at. Same thing for other countries. UK toll free numbers for example are routed through 3 providers: public.sip.magrathea.net, selfnet.at and freenum.sip.telecomplete.net. But only the last one worked for me. This means that companies like Selfnet.at and Magrathea.net offer to route toll free calls but they do not live up to their promises.

I exchanged a couple of mails with Duane (aka evilbunny) of e164.org. Here are some of my observations:

• Being able to call toll free numbers through SIP is a great benefit to people living outside those particular countries. Voxalot and e164.org make this an almost transparent procedure.
  
• Unfortunately some providers do not live up to their promises. This makes it a bit less transparent and it could result in a bad Voxalot/e164.org user experience (I had to add an extra rule to my dial plan disabling ENUM for toll free numbers in The Netherlands).
  
• A solution would be to regularly check if providers are still routing toll free traffic as they originally promised. E164.org already sends "SIP probes" to weed out problematic entries from its database. I can only assume that toll free providers are currently exempt from these probes.
  
• According to the e164.org FAQ, "providers offering toll free calls get paid per minute to terminate your calls to the phone network". So it is in their best interest to provide a good service. (Temporarily) dropping them from the e164.org database will probably speed this up.
  
• Technically these providers are not the real owners of the toll free numbers. The numbers have probably not been verified like the other numbers in the e164.org database. A couple of days ago MarkosJal wanted to know how to register hundreds of numbers on e164.org. There was no reply but I think it is a similar situation as with the toll free providers.
  
• So here is a fundamental question: who decides who is authorative for these numbers? What if there are providers with more nefarious intentions? For example, Airbus could start a provider and offer to route calls to Boeing "for free". And the United States could do the same for calls to Iran. (Ok, these are far fetched examples but you get my idea).
  
• Owners of toll free numbers can actually add their own SIP address to the e164.org database, overriding the route to the default provider(s). I don't know if there are toll free number owners who do this. It would save them some money, although it is probably small change considering the current number of e164.org users.
  
• E164.org could offer an optional "strict" mode in which only numbers that have actually been verified are resolved. I assume that this is the method used by the other ENUM roots (e164.arpa, e164.info, enum.org etc.).
  
• Your VoIP service provider such as Voxalot or Pennytel could decide to route toll free calls itself, for example using SIPbroker instead of ENUM. A call to +44-800-xxxx would then go to *883844800xxxx. ENUM has the advantage that it is based on DNS so it is more distributed than a SIPbroker lookup.

Any other thoughts on this?

[chatalot]

I believe that there is also a situation where the owner of the toll free number is preventing calls from being connected from certain locations within the same country. If the toll free sip address provider is actually placing the call from one of these locations then it doesn't get connected.

I too have have found ENUM is not always reliable for UK toll free so I now specify my preferred provider as a VSP and always use the same one with ENUM disabled in the dial plans. Sipbroker is working ok for me with US toll free however.

[evilbunny]

Originally Posted by jack

[*]E164.org could offer an optional "strict" mode in which only numbers that have actually been verified are resolved. I assume that this is the method used by the other ENUM roots (e164.arpa, e164.info, enum.org etc.).

We sort of have this in place, all user verified numbers are given a preference of 100, all providers are given a preference of 200 and all non-geographical to geographical numbers are given a preference of 300.

Originally we allowed everyone to set their own preference and order, but changed this in subsequant policy choices to only allow people to set order, but not preference.

So these non-verified numbers can easily be excluded by ignoring anything with a preference over 100, also the system will return the most specific to least specific responses.

e164.org is a directory service, we just return information in our database, it's up to the people requesting the information to handle it in a way best suited to them. Other directory services use varying policies, for e164.arpa the policy can vary on a per country, or perhaps smaller basis, to find out the actual policy for inclusion for each directory you would need to do a lot of research as I doubt you can make sweeping claims like that and the claim actually be true.

[evilbunny]

I've thought about this some more, and the answer is rather obvious, if a particular provider can't route certain numbers we can list a more specific provider that can, or use a notel record to exclude anything useful from being returned.

thoughts?

[dariusvayne]

Well I suggest that a listing of specific providers concerning this service is a good try.