NOL Voice Over IP (VOIP)

Nile Online “NOL” is the first company to be granted a Voice over IP over VPN (VOIP/VPN) license in Egypt. The license allows NOL to offer voice services to its corporate customers provided that the given connectivity service is VPN (Frame Relay or MPLS). The voice service is carried in the form of IP packets and over NOL VPN network. NOL has developed the necessary platform to be able to provide such service. The platform includes SIP proxy server and voice gateways to convert the analog voice into IP packet stream.

Why VOIP ?
The emergence of VOIP is fundamentally changing the way voice services are delivered today. It is transforming the telephony market, as well as business models for telephony services. Today fixed & mobile voice operators deploy IP network to carry the voice traffic, which is known as NGN (Next Generation Network). There are many advantages of carrying the voice over IP network instead of the regular PSTN:
   Convergence between Voice & Data ensures better utilization of  the VPN bandwidth.
   Voice calls cost reduction.
   All traditional as well as new voices features are available.

VOIP@NOL
A corporate with multi branches can use the existing VPN network to carry its phone calls. A voice gateway is needed at each branch, which connects the voice devices (phone sets or PBX) to NOL VPN network. NOL has wide range of voice gateways that support from 1 to 30 voice channels. A SIP server allows each corporate to have its own dialup plan so that all branches can call each other.
VOIP Components
Different ports capacity can be provided starting from 2 ports and up to 30 ports. Each call requires minimum of 8 Kb/sec and could go up to 32Kb/sec depending on the used compression codec. For two concurrent Connections a 2-port VOIP gateway is required and 16Kb/sec clear bandwidth to the destination. Optionally uncompressed VOIP can be used, and in this case each channel will require 32Kb/sec.

Voice Gateway
Usually the voice gateway has two different types of interface: one of them is IP (Ethernet) and the other interface is voice. The voice gateway can provide connection to analog voice phone or digital PBX.

Soft Phones
Software Applications that come with computers are also good example of VOIP application. PC with soft phone application can connect to SIP proxy in order to get dial tone.
In all cases, the last mile can be either xDSL connection over Local Loop or ADSL over splitted line.

SIP Proxy
SIP proxy in VOIP network is like PBX or switch in the PSTN. The SIP proxy simply converts the phone number into IP. The SIP proxy must contain all the phone numbers & IPs of all the voice gateway devices.

IP Phones
IP phone is a phone set that connects to IP network rather than PSTN switch or PBX. The IP phone connects to SIP server in order to have the dial tone and does the necessary dialing plan.

VOIP over Local Loop
 This is a typical xDSL connection connecting to xDSL DSLAM and MPLS VPN with minimum of 64Kb/sec capacity.
This setup requires VOIP Gateway, xDSL modem and available DSL port on NOL POP side.

VOIP over ADSL
The only difference between this setup and the local loop setup is that, the used line is normal telephone line splitter (Data & Voice), and ADSL CPE connecting to IP-ADSL- DSLAM at NOL POP. The setup requires VOIP gateway, ADSL modem, and available ADSL port on IP-ADSL DSLAM.