c separation between users with traffic from one leaf being allowed to arrive at one or more roots but never being transmitted to other leaves as shown in Figure 7.23. It is anticipated to be an enabler for mobile backhaul and triple-play infrastructure. UNI is the physical interface or port that is the demarcation between the customer and the service provider. UNI is always provided by the service provider and in MEF terms it is a physical Ethernet Interface at operating speeds 10 Mbs, 100 Mbps, 1 Gbps or 10 Gbps. Transmission Networks Carrier Ethernet Network Point-to-Multipoint EVC Figure 7.22 E-LAN service using multipoint-to-multipoint EVC. Reproduced from C 2008 Metro Ethernet Forum [37] 7.4.2.3.11 CE Applications This section will look into the key applications that will make good use of Carrier Ethernet [29]: Aggregation and Metro Core: Ethernet pipes are scalable (exhibiting statistical multiplexing) and with the introduction of CE, are also reliable with the associated OAM, thereby making them the ideal choice for Aggregation and Metro Core pieces of the transport network. MPLS-TP will be suitable to use in these areas rather than the backbone. Data Centers: Network attached data-center desires variable bandwidth, latency sensitive service, protocol-agnostic transport - all of which can be effectively met through PBB-TE and MPLS-TP implementations of CE. Delay and Bandwidth Sensitive Applications: CE technologies are ideal for meeting the delay sensitivity and bandwidth intensity requirements of video traffic, gaming applications, etc. FTTx: CE will be highly efficient to carry over FTTH (fiber-to-the-transmission hub) and FTTC (fiber-to-the-cabinet) networks. Carrier Ethernet Network Figure 7.23 E-Tree service using point-to-multipoint EVC. Reproduced from C 2008 Metro Ethernet Forum [37] Next Generation Mobile Communications Ecosystem Backbone Network Layering Model IP/MPLS SONET SGSNs International/Inter MSSs/MGWs Fiber city Voice Traffic IP-Transit BSCs (CDMA) GGSN/PDSN IP-Transit Backbone Network L