Hello there Friends, I want to share with you about transport network layers at movile network access.
Network architectures for RAN backhaul in the IP/MPLS Forum’s MPLS Mobile Backhaul Initiative are defined for various Transport Network Layers (TNL) and mobile network generations. These scenarios are grouped as follows and comprise two basic categories: legacy (TDM, ATM, HDLC) and future (IP/Ethernet).
Network | Specification | TNL | Speed (approximate) |
GSM/GPRS (2G/2.5G) | TDM | 56 - 114 Kbps | |
EDGE (2.5G) | TDM | 236.8 Kbps – 473.6 Kbps | |
UMTS /HSDPA/HSUPA (3G) | R3, R99/R4 | ATM | ~384 Kbps (uplink) ~ 2 to 3.1 Mbps (downlink) |
R99/R5, R6 | ATM | ||
IP | |||
CDMA 1x-RTT (2.5G) | IS-2000 | HDLC or TDM | 144 Kbps |
CDMA 1x EV-DO (3G) | IS-856 | IP | ~ 1.8 Mbps (uplink), ~ 3.1 Mbps (downlink) |
Mobile WiMAX | WiMAX Forum Network Access Architecture R1.1 | IP | 50 Mbps |
Long Term Evolution (4G) | R7/R8 | IP | > 50 Mbps (uplink) > 100 Mbps (downlink) |
In the legacy environment, RAN equipment communicates via either TDM or ATM TNLs and are connected with a T1/E1 interface, or with an Ethernet interface (Fast Ethernet) if TDM or ATM is encapsulated over Ethernet via IP or MPLS. The functionality necessary to transport legacy traffic over MPLS can be performed either at the edge node, the access node, the access gateway or directly in the RAN equipment. The HDLC layer features in CDMA 1x-RTT and covers RAN equipment communicating by means of HDLC-encoded bit streams.
In R5 3G, LTE and mobile WiMAX environments, the RAN equipment interfaces use the IP TNL – either at the Iub interface (for 3G) or on R7/R8 for LTE or mobile WIMAX. Mobile traffic over IP TNL can be transported either via Ethernet pseudowires or regular IP/MPLS TE tunnels over MMBI’s mobile backhaul network. IP termination can take place either at the edge node, the access node, the access gateway or directly at the RAN equipment. Various deployment scenarios arise depending on the location (and the extent) of MPLS technology in the mobile backhaul network and whether it comprises both the access and aggregation sections of the network or just the aggregation section. For further details on the MMBI reference architecture please visit: http://www.ipmplsforum.org/
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