Product Description
IP Office 8.1
© 2012 AVAYA All rights reserved.
Page 254
Issue 26.k.- (16 August 2012)
8.
IP Telephony
Technological innovation is changing the way we communicate. This time it is coming in the form of changing
the way telephone calls are transmitted. It brings with it several new capabilities that change the meaning of
the phrase telephone call through the use of Voice over Internet Protocol (VoIP). Basically, VoIP means "voice
transmitted over a packet data network." VoIP is often referred to as IP Telephony because it uses the IP
protocols to make possible enhanced voice communications throughout the world, wherever IP connections
have been delivered. IP Telephony unites a company’s many locations- including mobile workers- into a single
converged communications network. Telephony calls using VoIP go above and beyond what’s been possible in
the past. When it comes to placing telephone calls, VoIP provides a range of support services and features
unequalled in the world of telephony, but above all delivers them at low cost.
How Does VoIP Work?
Voice over Internet Protocol means basically what the acronym states: Voice travels over an Internet Protocol.
Internet Protocol refers to the type of rules that the network uses to send and receive signals. IP Telephony
works by converting voice communications into data packets. Conveniently, it runs on the popular Ethernet LAN
(local area network) technology, which currently supports over 96 percent of the worlds companies’ LANs.
Circuit-switched or Time-Division Multiplexed Telephony
Before digital networking with the Internet took off, everyone had to use the "Plain Old Telephone
Services" (POTS). These run over a network called the Public Switched Telephone Network (PSTN). The PSTN
has been around since the telephone was invented in either analog or digital form using circuit switched
technology where the telephone call gets exclusive bi-directional use of a wire – or circuit – while the call is in
progress. Because the circuit is exclusive to each conversation, PSTN and private branch exchanges (PBXs)
must be sized to cope with peak demand and have enough circuits available for all expected conversations. This
is not a flexible approach and results in a lot of infrastructure investment that the telephone companies need to
recoup, via the cost of access charges and calls. The Internet has changed this – where data services have
driven down access charges and allowed voice to "travel for free" over a multipurpose data network.
Packet-Switched Telephony
Unlike circuit-switched connections, which always require use of dedicated bi-directional circuit for the duration
of a call, VoIP technology has enabled telephony and other new and novel features and services to run over
fixed and wireless networks including private local area networks. These newer network types use packet-
switched protocols. Packet-switched VoIP puts voice signals into packets. Along with the voice signals, VoIP
packets include both the sender’s and receiver’s network addresses. VoIP packets can traverse any VoIP-
compatible network. Along the way, they can choose alternate, shared paths because the destination address is
included in the packet. The routing of the packets is not dependent on any particular network route which
means the network provides can provide a reliable service at a fraction of the cost of circuit switched providers.
What Advantage Does IP Office Have?
IP Office can provide support of PSTN, SIP, POTs, digital time division multiplexed telephones AND digital IP
telephones all on the same system. This means you don’t have to abandon the past to embrace the future, IP
Office allows all the technologies to co-exist. IP Office connects to the PSTN and to IP trunks (the VoIP
equivalent) so providing a "Hybrid" PBX function – where both legacy and future technologies can be used
together to minimize operating costs and optimize business communications through both voice and data.
IP Office has digital telephones built on both TDM and IP technology that provide the same user interface
offering a flexible choice of solution that can mix, for example TDM telephones in the office and IP telephones at
a remote site of at home. With the choice of IP telephones including real and virtual (software) telephones, IP
Office can take communications to a new level.
Buying IP Office allows you choice – you can use the pure POTs or the pure VoIP capabilities of IP Office, or use
both at the same time to allow seamless technology transition of your business without the disruption of having
to choose between them now.
