Section: C.2.1 Protection against wrap around of counter in the USIM
Content: The USIM will not accept arbitrary jumps in sequence numbers, but only increases by a value of at most . Therefore (before applying the freshness conditions of Annex C.2.2) the received sequence number SQN shall only be accepted by the USIM if SEQ-SEQMS ≤ . If SQN can not be accepted then the USIM shall generate a synchronisation failure message using SQNMS. Conditions on the choice of : (1) shall be sufficiently large so that the MS will not receive any sequence number with SEQ - SEQMS > if the HE/AuC functions correctly. (2) In order to prevent that SEQMS ever reaches the maximum batch number value SEQmax during the lifetime of the USIM the minimum number of steps SEQmax / required to reach SEQmax shall be sufficiently large.