NEC Electra Elite IPK II System User Manual page 602

Document Revision 4C
For this feature, the Media Gateway 16 is installed and assigned as a VoIP MG16 ETU. Each Media
Gateway supports IP signaling for up to 16 (SIP Trunks and/or SIP Stations) and reduces the maximum
capacity of SIP Trunk/Stations in accordance with the number of registered SIP Stations or SIP Trunks.
A maximum of 16 PVA(X)-U( ) ETUs can be installed supporting the maximum of 200 SIP Trunks (refer
to Table 2-44 KSU Power-Based Calculator Chart on page 2-1044
SIP Trunks can operate in two modes:
SIP Trunking – provides connectivity to a SIP service provider.

SIP Interconnect – provides connectivity to other IPK II systems.

Depending on the requirements and resource allocation in the LAN/WAN, the
SIP Trunk can be configured to use any of the following voice compressions:
G.711 -Law – Highest Bandwidth

G.729 (a) – Most often used

The minimum bandwidth requirements for each voice call is listed below. This includes all the overhead
of VoIP communication, including signaling.
Codec
G.711

-Law
G.729
Note 1:
Note 2:
SIP signaling stack resides on the CPU II.

The MG16 contains a regular TCP/RTP/IP stack that can handle real time media. The MG16 ETU

is an end-point on the IP network from the network administration perspective.
Speech-connection audio quality depends entirely on the available bandwidth between the Voice

over IP end points in the data network. Because Internet is an uncontrolled data network compared
to an Intranet, using this application in Intranet WAN environment with known (or controlled and
assured) Quality of Service (QoS) is highly recommended.
A static IP Address is required for each MG16 in the network.

2 - 578
Receive
Transmit
Data
Data Rate
Rate
90 Kbps 90Kbps
34 Kbps 34 Kbps
This includes the overhead of VoIP communication, including signaling.
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.
in the Universal Slots feature).
Time
Packetization
Between
Delay
Packets
20 ms 1.5 ms
20 ms 15.0 ms
Electra Elite IPK II
Default Theoretical
Jitter Buffer Maximum
Delay MOS
2 datagrams 4.4
(40 ms)
2 datagrams 4.07
(40 ms)
IP Trunk (SIP) – MG16