NEC Electra Elite IPK II System User Manual page 562

Document Revision 4C
An on-board 10 Base-T/100 Base-TX connector provides a WAN/LAN connection. Voice and signaling
data to/from the IP stations are converted into IP Frames and transmitted through the Data
Communication IP Network Intranet or Internet. Media Gateway 16 supports station-to-station direct
RTP connections (peer-to-peer) for calls between IP telephones. Each Media Gateway 16 application
can support up to 16 TDM Talk paths. Although, one Media Gateway Card can support 256 IP MEGACO
Stations, but only provides 16 simultaneous talk paths across the TDM highway.
The MG Application contains a regular TCP/RTP/IP stack that can handle real-time media, supports
industry standard MEGACO (H.248) communication on the WAN side, and interfaces with the Electra
Elite IPK II.
For this feature, the Media Gateway 16 is installed and assigned as a VoIP MG16 ETU. Each Media
Gateway 16 supports IP signaling for up to 16 Phones and reduces the maximum capacity of IP stations
in the system by 16.
There can be only one Media Gateway Controller assigned in the Electra Elite IPK II. This determination
is made in KSU Programming [PRG 84-05-03] Master/Slave determination. The Media Gateway
Controller interprets UDP signaling messages between the Elite IPK II Processor and IP Stations. Any
additional MG16 ETUs added to the system are called Media Gateway cards. The media gateway card
controls and interprets RTP messaging from the IP Phone to the Elite IPK II Processor.
If a non-IP Phone (e.g., POTS, multiline terminal), or trunk line is required, a DSP resource is needed. If
while on a peer-to-peer call, DSP resources are not used and the MG16 port is not accessed, only Media
Gateway Controller processing is used. If, while on a peer-to-peer call, a conference call is formed, the
peer-to-peer connection is released and a new non peer-to-peer connection is created using the MG16
DSP resources – two ports are used on the MG16 ETU. If the third party drops out of the conversation,
the call reverts to a peer-to-peer call.
A maximum of 16 PVA(X)-U( ) ETUs can be installed supporting the maximum of 256 IP stations (refer
to Table 2-44 KSU Power-Based Calculator Chart on page 2-1044
The MG supports only those vocoders that are approved to provide toll-quality speech path. The
following voice compression methods are supported for the IP Station (MEGACO) application:
G.711 Law – Highest Bandwidth

G.729 – Mid-Range Bandwidth

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Electra Elite IPK II
in the Universal Slots
IP Station (MEGACO) – MG 16
feature).