Mobile networks have been designed up to this point
for circuit- switched voice. Wireless networks were designed
in a hierarchal fashion to aggregate, authenticate, manage and
direct calls. A BSC aggregates calls from multiple base
stations, allocates radio channels, enables handoffs between
base stations and passes on calls to an even more centralized
mobile switching center.[17] As packet data networks
emerged, they were overlaid on the existing voice-centric
architecture, using the BSC for the same mobility management
functions and adding the SGSN and GGSN in the case of
GSM/UMTS and a PDSN in the case of CDMA to route and
manage data sessions, as well as to connect to the Internet or
appropriate IP network. As data traffic is increasing rapidly,
this voice centric architecture has become cumbersome and
harder to manage with too many network entities. Flat
network architecture removes that voice-centric hierarchy
from the network. Instead of overlaying a packet data core on
the voice network, separate and much-simplified data
architecture can be implemented that removes the multiple
elements of the network chain. BSC functions are divided
between Base station and media gateway router. The base
station will communicate directly via 3GDT (3G direct tunnel)
with media gateway over WAN (Carrier Ethernet, MW,
DWDM etc.). Some of the functions of BSC/RNC such as
Radio resource management, Radio Bearer Control, and
Dynamic allocations of resources will be handled by base
stations, while functions such as Distribution of paging
messages, Security will be functional by mobility manager,
located in Gateway router. This approach has clearly visible
advantages. It will save a significant amount of Capex and
Opex as, service provider will have little hopes and fewer
network entities. By reducing the number of hops in the
network, data travels faster between end points, greatly