Outgoing Caller ID CNAM FAQ
Posted: 10/08/2009
We get a lot of questions from users asking why their friends only see the number in the caller ID and not their name.
This generally only occurs on SIP-PSTN calls and not SIP-SIP calls. Why? Well, to make a long story about lax regulations short:
Call ID info for the PSTN is generally stored on a CNAM database provided by the serving CO. All ILECs always keep this database completely up to date because they run it and it's their customers in it. However, when it comes to CLECs and other network carriers along the way, there is no firm agreement or rules governing outgoing CNAM. So even if we do send CNAM data, there is no guarantee that all of the network carriers your call takes along the way will pass this info on. VOIP providers can overcome this problem by paying a third-party CNAM service to keep this up to date, but this is costly and the majority of providers simply don't have the money to put out for such a small thing.
SIP to SIP calls will almost always show name because the call is never touching the PSTN and is entirely digital.
There's some brief info here about this, but not a lot - google is really your friend if you want to know more. http://www.voip-info.org/wiki/view/CallerID
This generally only occurs on SIP-PSTN calls and not SIP-SIP calls. Why? Well, to make a long story about lax regulations short:
Call ID info for the PSTN is generally stored on a CNAM database provided by the serving CO. All ILECs always keep this database completely up to date because they run it and it's their customers in it. However, when it comes to CLECs and other network carriers along the way, there is no firm agreement or rules governing outgoing CNAM. So even if we do send CNAM data, there is no guarantee that all of the network carriers your call takes along the way will pass this info on. VOIP providers can overcome this problem by paying a third-party CNAM service to keep this up to date, but this is costly and the majority of providers simply don't have the money to put out for such a small thing.
SIP to SIP calls will almost always show name because the call is never touching the PSTN and is entirely digital.
There's some brief info here about this, but not a lot - google is really your friend if you want to know more. http://www.voip-info.org/wiki/view/CallerID