This object represents the type of MS to which the
charging profile selected by cgprsAccPtChgProfile is
applied on this APN. Different types of MS -
A roaming MS belongs to a MME/SGSN of a different PLMN.
A visitor MS is one whose IMSI value belongs to a
different PLMN. A home MS is neither roamer nor
visitor, i.e., IMSI and MME/SGSN corresponds to same PLMN.
A roamer/visitor is said to be Trusted/Friendly if
the different PLMN is a trusted/friendly PLMN.