Definition
Voice over IP (Internet Protocol) is the technology for transmission
of voice over packet switched networks. VoIP is also known as Internet
telephony, IP telephony, and packetized voice.
The technology is a real shift from using the traditional circuit
switched network, which has dedicated 64 Kbps of bandwidth reserved
end to end. The current circuit-switched system is connection oriented
in which the user picks up the phone. The dial tone indicates resources
are available in central office. After dialing the number, the signaling
system (SS7) allocates resources through network. One usually has
to wait for their party to answer. A fast busy signal indicates
congestion in the network.
VoIP Motivation
From a business perspective the trends show the integration of
voice, video and data in multiple applications. Also the amount
of bandwidth consumption is 8:1 in favor of packet-based networks.
Packet-based networks such as IP help reduce the rising communication
costs. Also, a single network is much easier to manage. Most of
all from a consumer perspective, making calls through packet networks
is much lower than circuit switched networks. . Better use of private
networks Statistical multiplexing Lower costs from long distance
carriers Avoid the costly tariffed PSTN over low-cost packet network.
Market Data
According to Cahners In-Stat Group the VoIP gateway market will
see exploding growth. From a US $61 million in the year 1998, the
worldwide VoIP gateway market will exceed US $3.8 billion. This
translates into a 280% CAGR (Compounded Annual Growth rate).
VoIP Technology, Types, Issues and Xilinx Solutions
VoIP is an emerging technology defined under the H.323 set of protocols.
It specifies components, protocols and procedures that provide multimedia
communication services such as real-time audio, video and data over
packet networks. Packet based networks include IP-based LANs, enterprise
networks, MANs, WANs. The protocols specified by H.323 are - audio
CODECs; video CODECs; H.225 registration, admission, and status
(RAS); H.225 call signaling, H.245 control signaling, real-time
transfer protocol (RTP), real-time control protocol (RTCP).
VoIP can be found in several flavors such as FoIP (Fax over Internet
Protocol), VoDSL (Voice over Digital Subscriber Line) and VoCable
(Voice over Cable).
VoIP faces issues such as delay, jitter and packet loss that need
to be addressed before the solution becomes a viable means for providing
voice communications over packet networks.
Xilinx's Spartan-II programmable logic solutions offer the flexibility
to build products that can be reprogrammed in the field at costs
unparalleled to any programmable solution. Please view the presentation
to see how Xilinx solutions can help you build products in this
fast evolving market place.
|