The scope of this Recommendation covers the negotiation and encapsulation of Data Compression, Secure data compression, authentication and encryption over fi-ame relay. These protocols are based on PPP Link Control Protocol (IETF RFC 1661) [13] and PPP Encryption Control Protocol (IETF RFC 1968 [14] and 1969 [15]). This Recommendation applies to Unnumbered Information @JI) fi-ames encapsulated using 4.933 Annex E [7]. It addresses data compression and privacy on both permanent virtual connections (PVC) and switched virtual connections (SVC).