lay model where ATM is used at Layer 2 and IP is used at Layer 3. By using MPLS, carriers can migrate many functions of the ATM control plane to Layer 3, simplifying network management and network complexity. Carrier networks may be able to migrate away from ATM altogether, which means eliminating ATM in carrying IP traffic. The following list identifies important Internet Drafts supporting MPLS. The Internet Drafts that are now on the IETF standard track as of July 20, 2001 are as follows: RFC 2702-Requirements - for Traffic Engineering over MPLS Identi- fies the functional capabilities required to implement policies that facil- itate efficient and reliable network operations in an MPLS domain. These capabilities can be used to optimize the utilization of network resources and to enhance traffic-oriented performance characteristics. RFC 031-Multiprotocol Label Switching Architecture Specifies the architecture of MPLS. RFC 3032-MPLS Label Stack Encoding Specifies the encoding to be used by an LSR in order to transmit labeled packets on Point-to-Point Protocol (PPP) data links, on LAN data links, and possibly on other data links. Also specifies the rules and procedures for processing the various fields of the label stack encoding. RFC 3034-Use of Label Switching on Frame Relay Networks Specifi- cation Defines the model and generic mechanisms for MPLS on Frame Relay networks. Extends and clarifies portions of the MPLS architecture and the Label Distribution Protocol (LDP) relative to Frame Relay networks. Chapter 7 RFC 3035-MPLS using LDP and ATM VC Switching Specifies in detail which procedures to use when distributing labels to or from ATM-LSRs when those labels represent forwarding equivalence classes (FECs) for which the routes are determined on a hop-by-hop basis by network layer routing algorithms. Also specifies the MPLS encapsulation to be used when sending labeled packets to or from ATM-LSRs. RFC 3036-LDP Specification Defines a set of procedures called LDP by which LSRs distribute labels to support MPLS f