The Generic VoIP Gateway: A business model for telcos

1
The Generic VoIP GatewayA business model for
telcos

• Michael Haberler
• IPA/nic.at

2
backdrop

• there already is VoIP on the public Internet
• there will be ENUM-only VoIP number ranges
• in AT telcos will be encouraged to terminate on
  the Internet, or transit to a telco who has a
  gateway
• iLECs LD operators will carry most of the PSTN
  traffic destined for these number ranges
• they are in excellent position to terminate these
  calls and grab the gateway business
• were considering first the PSTN-gtInternet call
  leg

3
The ENUM-only number range in Austria

• will be 43 780 abcdef
• a registration of the ENUM domain will be the
  number allocation
• a cancellation of the ENUM domain will relinquish
  the number
• easy, cheap, one-step process
• conceptual role decoupling of number allocation
  and gateway operator

4
the roles

• the user
• the ENUM registry
• the ITSP ENUM registrar
• the telco handling the gateway traffic

5
the interworking
PSTN ENUM-only number range
ITSP
6
early exit from the PSTN

• iff the range can be determined in lt 7 digits,
  any telco could use a GG anywhere and exit
  traffic early from the PSTN.
• this could be used for arbitrage or a cheap
  global number while still retaining
  reachability if no GG is used.
• a possible migration path from geographic ranges
  to 87810

7
result

• The GGO might or might not provide ITSP hosting
  service.
• that is, he might not have a service contract
  with the user.
• Therefore he is also not limited to his user base
  every call can be gateway regardless of ITSP.
• Assumption
• termination revenue gt termination cost (IP GG
  capex/opex)
• with proper authentication and billing, the same
  gateway can also handle calls Internet-gt PSTN
  with certified callerID.

8
prerequisites

• an ENUM-only number range
• properly set up, such a gateway can handle
  several number ranges, e.g. 43 780 abcdef as
  well as 87810 abcdefghij
• for early exit from the PSTN, range must be
  signifcant after no more than 7 digits
• a gateway which does the right thing depending on
  NAPTR service contents
• doable for SIP, H.323 with Cisco SS7 softswitch
  and AS5XXX (ISDN) Asterisk, too
• nic.at will do a proof-of-concept setup
• escape hatch possible for further, not yet
  defined ENUM service types by drop insert
  configuration of gateways to bounce unknown
  enumservices to a (future) downstream gateway.