Chapter 3 System Features
DSP2 Voice Server Module
3-74
255-700-025
PacketStar
™
Access Concentrator 60 User Guide
, Issue 1
Release 6.3.0
DSP2C Voice Server Features
Multiplexed or
Nonmultiplexed
AAL-2
The choice of multiplexed ATM Adaptation Layer 2 (AAL-2) has been added.
As the capacity of the DSP2C is 32 DSPs, up to 32 trunk groups can be
configured for multiplexing. Lucent recommends multiplexing voice and
data channels to reduce delay. AAL-2 implementation is based on ITU-T
Standards G.363, G.366.1, and G.366.2.
In nonmultiplexed voice and data processing, the payload length is a fixed
value of 40 bytes, which results in a dramatic reduction of latency (40 msec
end-to-end delay on the DSP2A, 60 msec end-to-end delay on the DSP2B,
and 22 msec end-to-end delay on DSP2C-Echo Canceler). See Appendix C in
this user guide for a comparison of standard AAL-2 and nonmultiplexed
AAL-2 cells per second (cps) at each compression rate.
Dynamic DSP
Resource Allocation
If a DSP fails on a DSP2A or DSP2B module, the connection admission
control (CAC) in the primary CPU will reassign the connections passing
through it to another DSP, if available. It will also move all the connections
from an entire module, should it fail, to another DSP2 module, if available.
The only restriction preventing re-routing is if compatibly configured DSP
resources are not available. (For example, a connection configured for G.168
echo cancellaton will not re-route to a DSP configured for G.165 echo
cancellation.)
Caller ID/Flash Hook
Signalling
Caller ID frequency shift keying (FSK) information is transmitted between
the first and second ring. This is valid when the called party is on-hook.
Flash signals are transmitted over flash signaling-capable trunks to initiate
internal calling features (i.e., Caller ID, call forwarding). As with FSK, the
transmission of flash signalling is only valid when the called end of a line is
off-hook. Flash signalling consists of signalling transitions from off-hook to
Permanent
Virtual Circuits
(CE-to-ATM)
Supported
Supported
Supported
Supported
Supported
Supported
Soft Permanent
Virtual Circuit
(SPVC)
Supported
Supported
Supported
Not
Supported
Not
Supported
Not
Supported
DSP A/B/C Mode
Hybrid
Configurations on
DSP2C Module
Supported
Supported
Supported
Supported
Supported
Supported
Mu-law/A-law-
PCM Code
Conversion
Supports
ITU-T G.711
Supports
ITU-T
G.711
Supports
ITU-T
G.711
Supports
ITU-T
G.711
Supports
ITU-T
G.711
Supports
ITU-T
G.711
Table 3-9. Matrix of Features and Standards Supported on the DSP2C Modes A, B and Echo Cancellation
Release 6.3.0
DSP2C
Non-Multiplexed AAL2 (Non-Mux-Aal2)
DSP2C
Standard AAL2
DSP2A
DSP2B
Echo Cancel
Mode
DSP2A
DSP2B
Echo Cancel
Mode