| 摘要 |
Whenever a roaming mobile subscriber's preferred long distance carrier is not ascertainable by a visited Public Land Mobile Network (PLMN), instead of utilizing a default long distance carrier selected by the visited PLMN, the serving mobile switching center (MSC) analyzes the received International Mobile Subscriber Identity (IMSI) number to determine the home network provider or PLMN associated with the roaming mobile subscriber. Using the determined home network provider data, the serving MSC retrieves the correlated home PLMN preferred long distance carrier data from its associated register. A long distance carrier specified by the retrieved data is then utilized by the serving MSC to serve all long distance calls originated from and forwarded by the roaming mobile station. |
