This document provides the Network Architecture Model (NAM) for the Ultra Mobile Broadband (UMB) system. PURPOSE This document provides the Network Architecture Model (NAM) for the Ultra Mobile BroadbandTM (UMBTM)1 system. The NAM supports the requirements in S.R0121 [1] and the Phase II requirements in S.R0113 [2]. The UMB system provides an additional Access Network (AN) to the overall architecture document in the All-IP NAM [3]. Except as documented in this document, all reference points and network entities in [3] are hereby incorporated by reference. Note: If not explained in this document, then refer to All-IP NAM [3]. This document was developed in conjunction with the network reference model of X.S0054-000-A [4] and TSG-X updates.