Alcatel-Lucent 7750 SR - Ethernet Evolution of GSM;UMTS Networks with ATM;TDM Backhaul

Services
7750 SR OS Services Guide Page 83
Ethernet Evolution of GSM/UMTS Networks with ATM/TDM
Backhaul
Some GSM/UMTS configurations using ATM/TDM backhaul can facilitate Ethernet backhaul
features with the installation of an Alcatel-Lucent 7705 Service Aggregation Router (SAR) at the
base station for the fully distributed case. The 7705-SAR supports TDM pseudowires for 2G BTS
traffic and ATM pseudowires for Node B traffic and Ethernet interfaces for HSPA and other local
traffic. The Ethernet Aggregation Transport Network (EATN) built using a 7450-ESS and 7750/
7710-SR portfolio meets all general requirements as well as features such as high availability, fast
restoration and stringent QoS are strong value propositions in this application. In some cases a
7450 ESS installed as part of EATN may require a Sonet interface on a network side based on the
existing physical network. When that is the case APS protection is needed to provide high
availability on the network side. However, the TDM pseudowires utilized for the 2G transport via
circuit emulation must be terminated at the MTSO for TDM connection to the BSC. In these cases,
an aggregated circuit emulation capability on the service router in the MTSO is required.
Therefore, a channelized OC-3/STM-1 CES capability interoperable with 7705-SAR is supported
for a completely integrated solution. Also, the ATM pseudowires utilized for the 3G transport
must be terminated at the MTSO for a concatenated OC/STM-n connection to the RNC. Finally,
the HSPA traffic can be aggregated at the MTSO on a standard Ethernet interface (typically GigE).
Alternatively, hub aggregation can be achieved by deploying lower capacity service routers or
higher capacity cell site aggregators at the hub locations. The TDM and ATM pseudowire
aggregation can be deployed at the hub site using Alcatel-Lucent 7705-SARs for physical E-1
connectivity, 7710-SR for channelized STM-n connectivity or a combination of both depending
on the number of cell site to be aggregated at the hub site.
In either scenario, the migration to Ethernet backhaul is gradual. Both Ethernet backhaul using
pseudo-wires concurrently with centralized SDH/SONET backhaul to allow a gradual migration
are supported. Both SDH/SONET backhaul and Ethernet backhaul is supported concurrently on a
single 7750-SR.