The SSM, core unit of the UMG8900, implements convergence,
switching, processing, and forwarding of service streams, provides
interfaces with the softswitch, and exchanges gateway control
messages.
The UMG8900 hardware platform is designed to support both time
division multiplexing (TDM) circuit switching services and IP
packet switching services.
The integrated packet and TDM switching platform addresses the
requirements for the TDM network and the packet network as well.
Therefore, the existing networks can evolve to all-IP networks
smoothly by software upgrade rather than hardware replacement to
reduce investment.
The UMG8900 supports the following types of frames: SSM-256,
SSM-160, and SSM-32. SSM-256 and SSM-32 frames can self-cascade
with frames of the same type or cascade with frames of the other
type. The SSM-160 frame supports only self-cascading. Different
cascading modes enable the optimum configuration of 32 to 7168 E1
channels in the synchronous digital hierarchy (SDH)/synchronous
optical network (SONET), E1/T1 and E3/T3 transmission modes to
protect investment effectively.
* The UMG8900, which is developed based on the softswitch
architecture, can serve in the evolution from time division
multiplexing (TDM) based global system for mobile communications
(GSM) networks to Internet Protocol (IP) based universal mobile
telecommunications system (UMTS) networks.
* The UMG8900 can support MSC Pool networking. Without upgrade of
devices in the access network, the UMG8900 can interconnect with
each MSC Server in the MSC Pool. Resources can be shared among MSC
Servers in the MSC Pool for load sharing. If an MSC Server fails,
The others MSC Server in the MSC Pool can take over subscribers of
the faulty MSC Server, that is, network disaster tolerance.
* VMGW
A virtual media gateway (VMGW) is a logical MGW. Multiple VMGWs can
be integrated physically. The UMG8900 supports the VMGW function.
An physicalUMG8900 can be configured to multiple VMGWs with
independent logical functions. The VMGWs are identified by the VMGW
ID and can be managed by different softswitches. The bearer
resources of the physical MGW can be allocated to different VMGWs
in exclusive or resource-sharing mode so that the flexibility of
the UMG8900 is enhanced.
* Dual-homing function, enabling the UMG8900 to automatically
switch to the slave MGC without interrupting services if the master
MGC fails.
* Stream Control Transmission Protocol (SCTP) multi-homing feature:
Multi-homing in SCTP refers to supporting multiple IP addresses.
That is, in an association the two sides can have multiple
addresses in an association, to provide more reliable end-to-end
multi-path transmission mechanism for the upper layer subscribers.
* IuPS feature to establish the connection between the radio
network controller (RNC) and the serving GPRS support node (SGSN)
The Iu PS interface is between the RNC in the access network and
the SGSN in the core network. In actual networking
applications, no physical connection may exist between the SGSN and
the RNC, and the UMG8900 is required to transfer services of the Iu
PS interface.
* IP-based Iu interface
The IP packet transmission technology is adopted in the radio
access network (RAN) and the core network, to build an all-IP
network where the RAN and the core network may share the IP bearer
network.
* IP-based A interface
Carriers' investment is protected and the IP-based core network
serves to a full extent. Compressed codes such as GSM FR, GSM EFR,
and GSM HR are transmitted, bandwidth is saved, transcode free
operation (TrFO) for the full voice channel is possible, Transcoder
Channel (TC) resource utilization is improved, and the voice
quality is enhanced.
* Acting as an IP multimedia media gateway (IM-MGW) to implement
the service interworking between the IP multimedia subsystem (IMS)
domain and the circuit switched (CS) domain and the transparent
transmission of H.264 and moving pictures experts group (MPEG)4
video codes.
* The UMG8900 can work with the MGC to act as a visited mobile
switching center (VMSC), tandem mobile switching center (TMSC), or
gateway mobile switching center (GMSC) in the GSM or R99 network.
The UMG8900 can independently act as a media gateway (MGW) in the
R4 network or an IP multimedia-MGW (IM-MGW) in the IP multimedia
subsystem (IMS).
