1. DSR TIF User's Guide
  2. Introduction
  3. IAM/SAM Splitting

1.7 IAM/SAM Splitting

When the CdPN parameter in the ISUP message grows too long after TIF services have added Routing Numbers (RNs) or other prefixes or delimiters, the ISUP message needs to be split. A destination-based SPLITIAM configuration option and a TIFOPTS SPLITIAM configuration option can be used for determining when to split an internationally formatted ITU ISUP IAM message into one IAM message and one SAM message.
  • When the number of Called Party digits is greater than the number of digits specified in the SPLITIAM option value (15-31 digits), the IAM message is split.
  • The IAM message is encoded with the number of leading Called Party digits specified in the SPLITIAM option value.
  • The SAM message is encoded with the remaining Called Party digits, up to the number of digits specified in the SPLITIAM option value.
  • Any Called Party digits that remain after the ISM and SAM encoding are discarded.
  • The SAM message is encoded with the same OPC, DPC,SLS, and CIC that are in the IAM message.
  • If the SPLITIAM option value is 15-31 in the Destination table entry associated with the DPC in the incoming message, that destination-based option value is used as the maximum CdPN length.
  • If the SPLITIAM option value is none in the Destination table entry associated iwth the DPC in the incoming message , and the TIFOPTS SPLITIAM option value is 15-31, the TIFOPTS SPLITIAM value is used as the maximum CdPN length.
  • If both SPLITIAM option values are none, IAM/SAM splitting is not enabled for the message. Up to 32 Called Party digits are encoded in the IAM message and any remaining digits are discarded.
  • When splitting is enabled for a message and the maximum CdPN length is 15-31, then that number of digits is encoded in the IAM message. Any remaining digits (up to that value) are encoded in a trailing SAM message. Any remaining digits after filling the SAM message are discarded.
  • The SAM message is encoded with the same OPC, DPC, SLS, and CIC that are in the IAM message.

Note:

If the DPC in the incoming message is not found in the Destination table, a UIM is generated and the message is discarded.

The SPLITIAM option is not applicable to ANSI ISUP messages; ANSI does not support SAM messages. Up to 32 Called Party digits are always encoded for ANSI ISUP messages.