NEC Electra Elite IPK II System - Page 687

Electra Elite IPK II Document Revision 4C
K-CCIS – IP with PVA 2 - 663
 The PVA(X)-U( ) ETU supports only those codecs that are approved to provide toll-quality
speech paths. The following voice compression methods are supported for the IP CCH for
NEAX application:
 G.711 -Law – highest bandwidth
 G.729 – mid-range bandwidth
 G.723 – lowest bandwidth
 Each voice call will require at least the bandwidth listed in the following table:
 Data calls (Modem Data) across the VoIP connection are only supported when G.711 Law
Codec is used.
 The PVA(X)-U( ) ETU contains a regular TCP/RTP/IP stack that can handle real time
media. The PVA(X)-U( ) ETU, from the network administration perspective, is an end-point
on the IP network.
 The PVA(X)-U( ) ETU with IP CCH for NEAX application loaded uses Common Channel
Interoffice Signaling over IP networks. Currently, this protocol does not allow
communications across networks where Network Address Translation (NAT) is performed.
 The audio quality of speech connections depend greatly on the available bandwidth
between the PVA(X)-U( ) ETUs in the data network. As the internet is an uncontrolled data
network compared to an Intranet, you should use this application in Intranet WAN
environment, with known (or controlled and assured) Quality of Service (QoS).
 If any network where the PVA(X)-U( ) ETU is connected uses NAT for connecting the voice
calls (including firewall), you should consult your network provider/administrator and
specifically request service for VoIP or real-time media support on your networks.
 A static IP Address is required for each PVA(X)-U( ) ETU in the network.
Codec
Transmit
Data Rate
Receive
Data
Rate
Time
Between
Packets
Packetization
Delay
Default
Jitter Buffer
Delay
Theoretical
Maximum
MOS
G.711
-Law
90 Kbps 90Kbps 20 ms 1.5 ms 2 datagrams
(40 ms)
4.4
G.729 34 Kbps 34 Kbps 20 ms 15.0 ms 2 datagrams
(40 ms)
4.07
G.723 25 Kbps 25 Kbps 30 ms 37.5 ms 2 datagrams
(60 ms)
3.87
Note 1: This includes the overheads of VoIP communication, including signaling.
Note 2: In voice communications, particularly Internet telephony, the mean opinion score (MOS)
provides a numerical measure of the quality of human speech at the destination end of the
circuit. The scheme uses subjective tests (opinionated scores) that are mathematically
averaged to obtain a quantitative indicator of the system performance. The maximum for
the Mean Opinion Score is 5.0.