RADIUS attribute from rfc6572
The Service-Selection attribute (Type value 146) is of type UTF-8 text and contains the name of the service or the external network with which the mobility service for the particular MN SHOULD be associated . The identifier MUST be unique within the PMIPv6 Domain when normalized using the selected normalization form for the particular PMIPv6 Domain deployment. For instance, uses the Normalization Form KC (NFKC). The MAG MUST include the Service-Selection attribute in the Access- Request sent to the AAA if the information was acquired, e.g., by operator-specific configuration. The AAA MAY include the Service- Selection attribute in the Access-Accept response message to the MAG even if it was not included in the Access-Request as a means of indicating the MN's default service. The Service Selection mobility option defined in can be used in PBU/PBA messages between the MAG and LMA. On the LMA-to-AAA interface, the LMA MAY populate the Service-Selection attribute in the Access-Request message using the service information found in the received PBU, if such a mobility option were included. The Service- Selection identifier should be used to assist the PBU authorization, the assignment of the MN-HNP, and the IPv4-MN-HoA as described in and . 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Service Identifier... ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: Service-Selection 146. Length: In octets, including Type and Length fields (>= 3). Text: This field is of type UTF-8 text and contains the Service Identifier with which the MN is associated.