format where mapping type is a parameter indicating a mapping algorithm to be used and where sp 1 represents the address of a first service platform and sp n represents the address of an n th service platform it should be noted however that the generic placeholder address is not limited to representing addresses of a fixed number of service platforms as will be described further below the generic placeholder address thus identifies addresses of one or more specific service platforms the mapping type parameter may be omitted if a default mapping algorithm is to be used each hlr 204 a and 204 b further include a mapping module 208 a and 208 b respectively in one embodiment the mapping modules 208 a and 208 b may implemented through appropriate computer programming instructions or processing logic executing on the computer on which their respective hlrs are running when a camel subscriber attempts to register in an appropriate functional entity of a mobile network such as in an msc 102 the msc 102 sends a registration request to the hlr with which the subscriber is associated the registration request includes an identifier of the subscriber for example if the subscriber u2018 b u2019 attempts.