Abstract: A communication network for transporting calls, where a service provision entity adds user identification information to call data of a call being set up by a non-dialable virtual subscription such that the subscriber behind the call being set up by the non-dialable virtual subscription may be identified at the network switching layer. This increases the manageability of the network and provides advantages for call interception.

Abstract: The present invention relates to a data structure and a method for, in a datastructure, managing sequences of symbols (e.g numbers or words). A solution with a double set of records is employed where the first set of records is defined by a linked list of records which are array records of pointers with one element for each symbol (e.g digit or letter). The second set of records is defined by strings where the complete sequences of symbols are stored. The managing of the data structures would suitably comprise storing, deleting and finding/searching the sequences of symbols.