Caller ID name presentation
Posted by Bob Russo on 13 May 2015 12:44 PM
Caller ID Name
Caller ID over SIP service performs somewhat differently than when working with PSTN type service. In that situation, the last central office passing the call will perform a check of a LIDB (line information database) to present the name in your phone’s display. This database relies on updates by the individual carriers to other carriers or a 3rd party database, this is called a DIP. While carriers act in a loose co-operation with each other for these updates, they are not always current with each other.
When a call is generated through SIP, the invite message contains the calling party name. The originating party provides this name based on it’s configuration and in some applications can be set to whatever the originator wants to present. If this call is presented from a SIP origination to a SIP termination without crossing through the PSTN, the terminating (receiving) end of the call will see that name as a general rule.
Some Platforms have the ability to use the number or IP address in the invite message to do a lookup in either their own, or a subscribed data base to find a name to present. ESI at this time does not provide this type of service however we are working on expanding our platforms abilities in this area. At this time we are limited to displaying whatever is contained in the invite message.
If the call passes through the PSTN the name (CNAM) will be stripped and the typical PSTN process will take over. This may lead to no match being made by the central office and generic names such as “New York” or “Unavailable” being attached, and then displayed at the receiving station.
Comparisons to the PSTN performance is not valid as the mechanics of the call flow are very different. Development of this feature on our platform may exceed the abilities of other platforms in the future, and as always, improving product features and functionality is continually moving forward.
The CNAM identity (caller ID name) that is associated with a number is pushed to the LIDB (line information database) by the various carries when the number ownership is established through the ordering procedure. This should match the information that is set in the configuration of the originating platform. This information is spread through the network of other carriers when those specific carriers update their version of the database according to their individual schedules. In some cases this may take several weeks.
This means that while a call to a party served by Carrier A may show the desired name, a call to a different party served by Carrier B may show as “unavailable” or even a previous name identity.
While ESI Hosted Services pushes the CNAM information during the implementation process for new and ported service, it is not unusual that calls received for the next week do not show the name to the called party. It should not raise a concern unless the condition continues for 2 weeks or more.