This Recommendation provides the definition and framework for providing a Packet Assembly/Disassembly function (PAD) that supports multiple protocols, or "Aspects", for access to a Packet Switched Public Data Network (PSPDN). The general framework for providing the multiple protocols is outlined, along with the basic requirements necessary within the PAD to enable the selection/modification of the protocol Aspects offered. This Recommendation on Multi-Aspect PAD (MAP), when implemented along with two or more PAD Aspects, will enable a user to access a PSPDN with one protocol, and to change to another protocol. MAP also brings the concept of simultaneous multiple sessions to the PAD as well. This is the framework specification for MAP. See also the various PAD Aspects for protocol and procedure alternatives supporting MAPs (e. g. Recommendations X.28, X.38, etc.).