Lucent Technologies PacketStar PSAX 2300, Руководство пользователя, Страница: 84 / 680

Chapter 3 System Features
User Interfaces
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PacketStar
®
PSAX 2300 Multiservice Media Gateway User Guide , Issue 1 Release 9.0.0
Lucent Stinger™ DSLAM, a CellPipe™ IAD or AdTran TA624.850, and a cen-
tral office voice switch, such as the Lucent Technologies 5ESS switch, or with
a Nortel DMS switch.
Operating on T1 circuits, the GR-303 digital loop carrier service has provi-
sions for both an open interface network architecture and a digital loop car-
rier system. The performance standards of the GR-303 interface are derived
from the high-level internetworking capabilities established in Telcordia
Technologies General Requirements 303, and allow a central office PSAX sys-
tem to interface with central office voice switching equipment as a remote
terminal.
The interface assigns and manages connections on a time slot management
channel (TMC) and supports operating functions on an embedded operations
channel (EOC), with each channel configured on I/O modules that support
the GR-303 interface protocol. The user guide details a configuration for one
GR-303 group using the ratio concentration of 2048 CRVs to 668 DS0s,
approximately a 3:1 oversubscription rate per DSP2C/D voice processing
chip. (A CRV is a call reference value that the 5ESS switch will map to a
phone number). The GR-303 specifications recommend connection concen-
trations from 1:1 up to 3:1, expandability from 2 to 28 DS1 circuits for each
GR-303 group, and expandability from 1 to 2,048 subscriber channels per
GR-303 interface group.
The oversubscription factor you can achieve depends on what modules con-
figuration is chosen. You can decide what ratio to oversubscribe the DS0/CE
resource. Higher channel densities per DSP chip resource and more AAL2
trunking groups are achieved by upgrading to the DSP2D Voice Server mod-
ule from the DSP2C.
The maximum number of GR-303 interface groups supported on the PSAX
system is 84. Loop emulation services provide multiplexed AAL2 PVC sup-
port for the PSAX system central office product line. Loop emulation services
allow voice traffic, DTMF, and signaling to be handled over the packet net-
work. The circuits can interwork with time division multiplexing (TDM),
ATM digital subscriber line (DSL), or GR-303 interfaces.
The PSAX system also supports these features:
•
Caller ID
• Call forwarding
•
Call transfer
• Call waiting
•
Cancel call waiting
• Customer callback
•
Speed dialing
• Three-way calling
•
Loop start line
• Visual and audio message waiting indicator
Because GR-303 software requires a large amount of memory, the feature
can be enabled or disabled as needed. If this feature is not needed, disabling it
allows the system to allocate more memory for other system functions.