Every subscriber has a mobile telephone number, and in many countries (not all), mobile number ranges are different from fixed line (land line) number ranges. In countries where the mobile number range is separate from the range for fixed line numbers, the country’s telecommunications regulator may issue numbers to mobile operators in blocks. These blocks can be used to identify the mobile operator to which the number belongs.
In countries where Mobile Number Portability (MNP) is not allowed, these prefixes can be used to determine the home operator, as the home operator equals the prefix operator. In countries where MNP is allowed, another source of porting information is required to determine the home operator, so the prefix operator is relatively meaningless and only indicates to which operator the number was originally allocated. In the world of SMS, the prefix operator can be important for routing, as some routes only support certain prefix/home operator combinations. Be careful of aggregators who only support prefix routing, as this implies, they do not support MNP routing, which is required in many countries to deliver a message effectively.