sents a group of packets that are provided the same treatment in routing to the destination. The definitions of MPLS were given by IETF, which has an MPLS working group. Management protocols like SNMP is widely used to gather traffic characteristics from routers in the MPLS network. This information can be used by management applications for provisioning and for traffic engineering of the MPLS network. Being an "any-to-any" network there are multiple challenges in management of MPLS. The biggest concern is to monitor performance and identify the service class when handling an application. The network management solution that offers traffic control should be able to identify existing paths and calculate paths that can provide the guaranteed quality of service. Some management solutions even reshuffle existing paths to identify optimal paths for a specific application. Multiprotocol support of a management solution will be useful when migrating to MPLS network. 9.7 IMS IMS (IP multimedia subsystem) is considered to be the backbone of "all-IP net- work." IMS was originally developed for mobile applications by 3GPP and 3GPP2. With standards from TISPAN, fixed networks are also supported in IMS, leading to mobile and fixed convergence. Use of open standard IP protocols, defined by the IETF allows service providers to use IMS in introducing new services easily. With multiple standardizing organizations working on IMS, it will cross the frontiers of mobile, wireless, and fixed line technologies. IMS is based on open standard IP protocols with SIP (session initiation proto- col) used to establish, manage, and terminate connections. A multimedia session between two IMS users, between an IMS user and a user on the Internet, or between two users on the Internet are all established using the same protocol. Moreover, the Fundamentals of EMS, NMS and OSS/BSS IMS network Application layer Session control layer Access layer Figure 9.6 Three layered IMS network. interfaces for service developers are also based on IP protocols. IM