国家重点实验室 2)network node As network evolves,except the switching function,it also performs transforming or mixing of user information,and has the functions of both control and management for users. Examples of network node: an IP telephone gateway could perform: Transforming coding between a/u voice in TDM with 64Kbps and IP voice coding,say G.729A with 8Kbps Transforming PSTN signalling and VolP signaling. More details in both later slides and Chapter seven of Access network PPT. 2) network node As network evolves , except the switching function, it also performs transforming or mixing of user information, and has the functions of both control and management for users. Examples of network node:  an IP telephone gateway could perform: • Transforming coding between a/μ voice in TDM with 64Kbps and IP voice coding， say G.729A with 8Kbps • Transforming PSTN signalling and VoIP signaling. More details in both later slides and Chapter seven of Access network PPT