6
Extended RADIUS attributes
The RADIUS protocol features excellent extensibility. Attribute 26 (Vender-Specific) defined by RFC 2865
allows a vender to define extended attributes to implement functions that the standard RADIUS protocol
does not provide.
A vendor can encapsulate multiple type-length-value (TLV) sub-attributes in RADIUS packets for extension
in applications. As shown in Figure 5, a sub-attribute that can be encapsulated in Attribute 26 consists of
the following parts:
 Vendor-ID (4 bytes long)—Indicates the ID of the vendor. Its most significant byte is 0; the other three
bytes contains a code that is compliant to RFC 1700. For more information about the proprietary
RADIUS sub-attributes of HP, see ―HP proprietary RADIUS sub-attributes.―
 Vendor-Type—Indicates the type of the sub-attribute.
 Vendor-Length—Indicates the length of the sub-attribute.
 Vendor-Data—Indicates the contents of the sub-attribute.