Avaya IP Office 8.1 Product Description page 255

IP Office and IP Telephony
In order to make use of VoIP, IP Office uses signaling protocols called H.323 , and Session Initiation Protocol
(SIP) which allow IP Office to establish end-to-end connections for the voice path through the IP network. It
ensures each end of the connection is able to transmit and receive voice and provides the network addressing
for end to end packet transmission. IP Office also allows for connecting between the different technologies by
translating the signals they use, for example an analog telephone may wish to connect to a VoIP destination.
This requires both the signaling and voice transmission to be translated – IP Office does this easily as it
contains technology elements called gateways and gatekeepers that enable translations to happen.
With a conventional telephone system you plug your analog or digital TDM telephone into an extension socket
connected to your PBX or Key System. With IP Telephony you connect your IP telephone to your IP PBX via the
LAN. There are two basic types of IP telephones:
· A physical telephone, which looks very similar to a standard telephone (IP Hard Phone)
· A software application (IP Office Video Softphone) which runs on the user's PC, allowing them to use
either a headset/microphone to make/receive calls anywhere they have IP connection
IP telephony has the advantage of allowing extensions to be deployed both locally and remotely through the
use of IP routing and IP VPN services.
When making use of IP telephony, there are a number of data centric considerations such as which data types
have priority on the IP network when there is contention. This is set with IP/TCP "quality of service" and should
not be ignored. In situations where LAN Bandwidth is limited, a quality of service capable LAN switch should be
used to ensure voice packets are transmitted with the required priority on the network. If not, the conversation
carried over IP appears as broken up (due to delays) or has unacceptable delays introduced in the conversation
(latency and jitter). With IP hardphones there is need for Power over Ethernet (PoE), or local phone power
supplies to be provided to the telephones as the IP telephones are no longer powered by IP Office – a list of
Avaya approved PoE options is available at the end of this section.
Product Description
IP Office 8.1
© 2012 AVAYA All rights reserved.
Page 255
Issue 26.k.- (16 August 2012)