Vodavi Discovery Ip Techical Guide

							viiiContents
Discovery IP Technical ManualAugust 1999 
						

							Discovery IP Technical Manual August 1999
1 Product Description/Overview
IP TELEPHONY
The Discovery IP, Vodavi’s IP telephony solution, supports communication between 
conventional telephony devices such as key systems and PBX using an Internet Protocol (IP) 
data network.  The Discovery IP enables the use of an IP path as the connection between distant 
telephone systems. A traditional telephone connection consists of a constant connection between 
two phones for the duration of a telephone call.  On a Public Switched Telephone Network 
(PSTN) or trunk circuit, the call occupies 64,000 bits/second (64 kbps) of bandwidth between 
the two ends, whether anyone is talking or not.  IP telephony technology compresses the voice-
data or fax-data stream by a factor determined by the algorithm used.  Compression may in some 
cases exceed a 10:1 compression ratio. A benefit of the compression is that it provides a 
conventional 64 kbps circuit to handle multiple calls.
The prevalence and existing infrastructure of IP connections make it a logical and economical 
medium for transporting voice and fax data.  IP is used worldwide for private and public 
networks.  The global Internet consists entirely of IP connections between millions of systems.
IP is a packet protocol, communicating through the use of data packets which can be interleaved 
with other packets on the same circuit.  IP is independent of the underlying transmission 
technology – it works equally well on a Local Area Network (LAN), frame relay, and dedicated 
private lines.  Its advantages include:
†connectionless per-packet routing so that intermediate failures of circuits or routers will 
efficiently and automatically be avoided without failure of the link between two endpoints 
(as long as an alternate path is available).
†multiple session support, so that more than one communication can be carried on the 
circuit at the same time.
IP has predominantly been a data protocol used for sending files and messages between 
computers. IP telephony has the additional advantage of permitting data and voice packets to be 
interleaved on the same circuits.  The global Internet now carries voice/fax as well as email and 
web pages, without any concern for the type of data in each packet. 
						

							1-2 DISCOVERY IP NETWORK COMPONENTS
Product Description/Overview August 1999
DISCOVERY IP NETWORK COMPONENTS
A Discovery IP network consists of an IP network between at least two endpoints, and devices 
to convert standard voice signals into IP data packets for transmission on the packet network.  
The devices known as gateways are the DISCOVERY IP units.  Each Discovery IP connects to 
loop start CO line interfaces on a key system or PBX and to an IP LAN.  A conventional router 
connects the LAN to a Wide Area Network (WAN) with connections to other DISCOVERY IPs.  
Multiple DISCOVERY IPs can be stackable-mounted to support many simultaneous phone 
calls.
Additional optional components include the following:
†Components used for remote management of the processes and configurations of 
DISCOVERY IPs.
†An optional Gatekeeper software module to provide H.323 compliance when integrating 
the Discovery IP with other gateway manufacturers products. The gatekeeper module 
installs on a separate Microsoft Windows NT based operating system PC located on the 
same network as the gateways.
IP TELEPHONY STANDARDS
The Discovery IP uses conventional telephony standards for connecting to the telephone 
network.  Foreign eXchange (FX) 2-wire circuits are the predominant types in the USA.  
Foreign Exchange Station (FXS) emulates a Central Office (CO) and is used to connect to the 
trunk side of a PBX or keyset.
The compression/decompression algorithms (codecs) used are G.723 for voice, and G.711 for 
fax.  G.723 coding uses 5.3 kbps, with a compression ratio of approximately 12 to 1, G.711 
coding uses 64 kbps, with a compression ratio of 1 to 1.  Digital Signal Processors (DSP) that are 
used run at 33 MIPs.
It should be noted that the Internet is not the ideal mechanism for 
telephone calls.  Most data communication between computers is 
not sensitive to small traffic delays between sender and receiver.  
Voice is very sensitive, in that users prefer a natural-sounding 
conversation.  This requires a minimum of delay, and interference 
in regard to the transmission of the voice packets.  Unfortunately, 
the Internet is growing rapidly and exhibits random areas of delay 
and congestion, so it is not a stable medium.  Voice conversation 
can be acceptable or not acceptable when using the internet as the 
transport medium. A privately-managed intranet will provide the 
best IP telephony voice quality. 
						

							DISCOVERY IP NETWORK APPLICATIONS 1-3
August 1999 Product Description/Overview
The industry-standard Ethernet 10/100BaseT LAN port provides connection to the data network 
infrastructure.  The voice/fax data packets may be routed, bridged or tunneled through another 
network to a remote Discovery IP where the voice/fax traffic is sent to a station (phone), CO, or 
PBX.
DISCOVERY IP NETWORK APPLICATIONS
The Discovery IP has several applications.  It is used as a connection between distant telephone 
circuits, which may be local telephone lines or connections to a company’s private phone 
system.  The major ones include:
†Telephone service between two or more locales
†Long-distance circuit replacement
†International connections between overseas countries and the US. 
						

							1-4 DISCOVERY IP NETWORK APPLICATIONS
Product Description/Overview August 1999 
						

							Discovery IP Technical Manual August 1999
2 Operational Modes
CALLING FROM POINT A TO POINT B
The Discovery IP is a conversion node where traditional voice telephone circuits are converted 
or packetized into digital information (IP packets) which are transmitted across a data network.  
At the other end of the connection, another Discovery IP converts the packetized voice back to 
analog information for the telephone network.  
The Discovery IP typically connects telephone systems together using the data network as the 
transport medium. The interconnection between the Discovery IP and the telephone system is 
done through loop start trunks.  The interconnection between the Discovery IP and the data 
network is typically with a Router over a Local Area Network (LAN) to the leased data line or 
Internet access line. Each Discovery IP has a unique IP address and can be grouped into a large 
network, dispersed geographically around the world, or simply placed between two 
geographically remote locations.
Discovery IP supports two (2) methods of call routing. The first is multiple unit or MAP, and the 
second is point-to point, or NOMAP. With multiple unit operation, the user accesses a CO-line 
connected to the Discovery IP. The Discovery IP then prompts the user for a phone number 
(programmable) for their desired destination. The user enters a phone number corresponding to 
the desired Discovery IP destination. The number dialed by the user is compared to a routing 
table in the Discovery IP. The table maps phone numbers to IP addresses of all the Discovery IP 
units in the network. The call then routes to the destination Discovery IP unit and rings the 
phone system as an incoming call on a specific CO line. With point-to-point (NOMAP), the user 
accesses a CO-line connected to the Discovery IP. The Discovery IP unit then accesses a distant 
Discovery IP unit programmed in the unit. No prompting is given to the user with this option.
Voice data traverses between the originating Discovery IP and destination Discovery IP in a 
manner determined by the voice compression/decompression algorithm (codec) used. The 
algorithms used are G.723 for voice and G.711 for fax. G.723 coding uses 5.3 kbps, with a 
compression ratio of approximately 12 to 1, G.711 coding uses 64 kbps, with a compression 
ratio of 1 to 1. 
At the end of the call, a Call Detail Record (CDR) may be generated.
ROUTING TELEPHONE/FAX CALLS
Multiple Unit Routing
The Discovery IP can route by prefix, area code, and default mappings when connecting 
multiple Discovery IP units to the network.  CDRs used for billing are written to a text file at the 
configuration-specified Discovery IP.  
						

							2-2 ROUTING TELEPHONE/FAX CALLS
Operational ModesAugust 1999
This mapping method is used when it is specified in the configuration wizard that more than two 
Discovery IP gateways are in this application (refer to Figure 1).
Figure 1: Internal Multiple Routing (MAP), and Point-to-Point (NOMAP) Diagrams
Point-to-Point (NOMAP) Routing
The AutoDial option enables all calls made through this Discovery IP to bypass any prefix and 
authentication dialing and be placed out of the NOMAP-specified destination Discovery IP.  The 
destination Discovery IP automatically calls the number, or goes off-hook to connect to the 
attached phone line(s) or switch.  NOMAP routes all calls originating at a Discovery IP point-to-
point to the Discovery IP at the configuration-specified IP address. The specified Discovery IP is 
the destination Discovery IP for all calls originating from the first Discovery IP.
This method will allow users to access a line or group of lines connected to the Discovery IP and 
place a connection to another Discovery IP without dialing any digits. This mapping method is 
used when it is specified in the configuration wizard that only two Discovery IP gateways are in 
this application (refer to Figure 1).
KSUIP
IPKSU212
Area Code
IPKSU770
Area Code
IP
KSU
512
Area Code
602
Area Code
Multiple Routing Diagram
Internet
KSUIPIPKSU
NOMAP Diagram
Internet 
						

							CALL DETAIL RECORDING 2-3
August 1999Operational Modes
CALL DETAIL RECORDING
Information collected in Call Detail Recording (CDR) includes the user identification number, 
number dialed, time of call, duration of call, type of call, IP address of originating Discovery IP, 
IP address of destination Discovery IP, and port used on each Discovery IP.
ACCESSING CDR
For internal Gatekeeper/billing, the CDRs are located in the file found in: tempest/billing/
 
directory called bills. The format of a CDR is:
,
						

							2-4 CALL DETAIL RECORDING
Operational ModesAugust 1999 
						

							Discovery IP Technical Manual August 1999
3 Prerequisites for Installation
PHYSICAL ENVIRONMENT 
NETWORK INFORMATION
The network configurations must be entered into the Discovery IP configuration program in 
order for proper communication to occur.  The following information is required for Discovery 
IP network configuration:
†Full hostname of the Discovery IP, including domain name
†IP address of the Discovery IP
†Subnet mask of the Discovery IP
†IP address of the default router/gateway for the Discovery IP
†Timezone of the Discovery IP unit 
Table 1: Physical Environment
Operating Temperature 5 to 45 °C
Operating Temperature Gradient 10 °C/hr maximum
Operating Humidity 20 to 80 %, non-condensing
Input Voltage, AC Power Supply 115 VAC (90-132 Vms) or 230 VAC (180-264 Vms)
Frequency 50-60 Hz
Maximum Input Current 6.0 A (115 Vms, 60 Hz), 3.0 A (230 Vms, 50 Hz)
Protection Overvoltage, overcurrent, short-current
Typical Output Power 250 W
Console and Auxiliary Ports Asynchronous serial, VGA, PS2 keyboard
Internet Access Dedicated internet connection (not DialUp)
Dimensions 3.5 x 19 x 20.7 in.
We i g h t 2 5  l b .