RADIUS attribute from rfc7268
Network-Id-Name
The Network-Id-Name Attribute is utilized by implementations of IEEE-802.1X to specify the name of a Network-Id (NID-Name). Unlike the IEEE 802.11 SSID (which is a maximum of 32 octets in length), the NID-Name may be up to 253 octets in length. Consequently, if the MAC address is included within the Called- Station-Id Attribute, it is possible that there will not be enough remaining space to encode the NID-Name as well. Therefore, when used with IEEE 802.1X , the Called-Station-Id Attribute SHOULD contain only the MAC address, with the Network- Id-Name Attribute used to transmit the NID-Name. The Network-Id- Name Attribute MUST NOT be used to encode the IEEE 802.11 SSID; as noted in , the Called-Station-Id Attribute is used for this purpose.Zero or one Network-Id-Name Attribute is permitted within an Access-Request, Access-Challenge, Access-Accept or Accounting- Request packet. When included within an Access-Request packet, the Network-Id-Name Attribute represents a hint of the NID-Name to which the Supplicant should be granted access. When included within an Access-Accept packet, the Network-Id-Name Attribute represents the NID-Name to which the Supplicant is to be granted access. When included within an Accounting-Request packet, the Network-Id-Name Attribute represents the NID-Name to which the Supplicant has been granted access. A summary of the Network-Id-Name Attribute format is shown below. The fields are transmitted from left to right. 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 | String... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 179 Length >=3 String The String field is one or more octets, containing a NID-Name. For details, see . A robust implementation SHOULD support the field as undistinguished octets.