The recorder filters the recorded verticals based on the Voice Recorder ID (or Cluster ID) defined for the TTPs. Filtering applies for both to establish media streams and processing calls from CTI messages. In general, the Voice Recorder ID(s) of the TTPs configured on the BT ITS switch side and the list of recorded Voice Recorder IDs configured on the recorder side must be consistent.

2N deployments

2N recording is not natively supported by the BT ITS system, but with consistent TTP allocation and configuration, the same vertical can be assigned to multiple TTPs, so each TTP is sent to two separate recorders. The duplicated streams can be correlated by a mapping between the TTP IDs (addresses). 2N recording deployments have two lanes: a primary and a secondary, which define the recorder group (both Recording Director and Media Recorders) recording the primary copy or the secondary copy of the calls.

The mapping/correlation algorithm is as follows:

• Each primary lane TTP has an odd Voice Recorder ID (or Cluster ID)
• The secondary pair has the next even number as the Voice Recorder ID (or Cluster ID)
• This implies that a device assigned to a timeslot must have the same trunk and channel/slot ID on the primary/secondary TTP

For example, the left handset of a turret is assigned to the TTP channel 1.1.1 (Voice_Recorder_ID.Trunk_ID.Channel _ID) then the secondary 2N pair must be assigned to TTP 2.1.1

Campus deployments

In a BT ITS campus deployment, the recording must be done on recorders closest to the given DC, sharing recorders across multiple DCs is not supported. CTI / LDAP / TMS is not aware of turret location in a campus deployment as the BT ITS system is a single switch deployed across two locations. The Voice Recorder ID(s) of the TTPs are intended to use for distinguishing recorder pools deployed in the different data centers.

The mapping/correlation algorithm is as follows:

• DC A turrets must be linked to recorders in DC A, so their TTPs must have a  DC A specific Voice Recorder ID and this ID should be configured on the recorder side as well to filter for these devices, respectively the same has to be done for the other DC as well
• if 2N is configured then the odd-even numbering rule must be taken into account when assigning Voice Recorder IDs

For example: 

• N+1 recorder redundancy in 2 DCs: DC A has Voice Recorder ID 1, DC B has 2, this means that the TTP channels 1.x.x will be handled by DC A and 2.x.x will be handled by DC B
• 2N recorder redundancy in 2 DCs: DC A has Voice Recorder ID 1,2, DC B has 3,4, this means TTP channels 1.x.x and secondary 2N pairs 2.x.x will be handled by DC A, 3.x.x and secondary 2N pairs 4.x.x will be handled by DC B