Ip Station (Megaco) - Iad (Integrated Access Device) - NEC Electra Elite IPK II System User Manual

Document Revision 4C
NAT Beater – Network Address Translation

For this feature, the IAD(8)-U( ) ETU is installed and assigned as an ESI(8)-U( ) ETU. Each IAD(8)-U( )
ETU supports up to eight IP Phones and reduces the maximum capacity of stations in the system by
eight.
A maximum of 14 IAD(8)-U( ) ETUs can be installed supporting the maximum of 112 stations (refer to
Table 2-44 KSU Power-Based Calculator Chart on page 2-1044
The IAD(8)-U( ) 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

Each voice call requires at least the specifications listed in the following table. This includes all the
overheads of VoIP communication, including signaling).
Transmit
Codec
Data Rate

G711 Law 90 Kbps
G729 34 Kbps
When an IP Soft Phone is connected, set Time Between Packets to 100 ms.

The IAD(8)-U( ) ETU contains a regular TCP/RTP/IP stack that can handle real time media. The

IAD ETU is an end-point on the IP network from the network administration perspective.
The IAD(8)-U( ) ETU uses MEGACO (H.248) Protocol to provide telephony services between

remote stations through the IP Network. This is an IETF/ITU standards-based protocol. Currently,
this protocol does not natively allow communications across networks where Network Address
Translation (NAT) is performed.
Speech-connection audio quality depends greatly on the available bandwidth between the stations

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.
When any network where the IAD(8)-U( ) ETU or any of its IP terminals is connected uses NAT for

connecting the voice calls (including firewall), consulting your network provider/administrator to
specifically request service for VoIP or real-time media support on your networks is recommended.
A static IP Address is required for each IAD(8)-U( ) ETU in the network.

2 - 532
Time
Receive
Between
Data Rate
Packets
90 Kbps 20 ms

34 Kbps 20 ms

IP Station (MEGACO) – IAD (Integrated Access Device)
in the Universal Slots
Packetization Default Jitter
Delay Buffer Delay
1.5 ms 2 datagrams
(40 ms)
15.0 ms 2 datagrams
(40 ms)
Electra Elite IPK II
feature).
Theoretical
Maximum
MOS
4.4
4.07