|
n a traditional PSTN,
the quality of service of the calls and continuous connection are very
dependable; so, in order for people to switch to IP telephony, the same
quality considerations must be maintained or excelled. With IP telephony
consisting of distributed elements, the entire architecture has to be
strategically managed to provide good service while at the same time
reducing the overload and maintenance costs.
Voice over Internet Protocol, or VoIP, solutions include
components such as end-user devices, PBX, gateways and gatekeepers, IP
network and several protocols that take care of the issues and
operations of a transaction. When a call is initiated, there are
distributed arrays of routers, which manage the call functions such as
identification of the destination, maintenance of the connection between
the IP and PSTN, billing management, and alerts about the incoming
transaction.
In this competitive VoIP market, VoIP solutions must be
able to meet needs such as high-speed interface, predictable
performance, quality of service and security. These factors drive
application development and infrastructure deployment. The routers
should be able to handle thousands of calls through increased bandwidth,
and they should also match the interface speeds in order to forward the
IP packets. The quality of service is maintained in the router by
addressing concerns such as exact sequencing of the packets so that the
call is clear and meaningful. Security features are to be implemented to
prevent hackers from accessing the infrastructure. This is managed by
enumerating the routers, which function as gateways and controllers as
private addresses, so they are not accessed through the public Internet.
A robust infrastructure deployment is complemented by application
development that adheres to various protocols that are mostly governed
by International Transmission Union (ITU) and Internet Engineering Task
Force (IETF). Several protocols are available, and the necessity of the
implementation depends upon the product groups. Signaling System Seven
(SS7) is a protocol that manages the establishment and termination of
calls. H.323 is a product-based communication protocol that signals the
call to the IP network and the end user.
RTP protocols address the concerns of real-time receipt of calls so that
the calls arrive in the same sequence. Media Gateway Control protocol
coordinates the actions of gateways. Session Initiation Protocol (SIP)
handles the setup and tear down of multimedia sessions between speakers.
With a combination of infrastructure and protocol, VoIP solutions
enable the customer to establish calls at a fraction of the rate of PSTN
lines, while at the same time maintaining quality.
Article Information
by Steve
Valentino, www.e-ipphones.com
source: goarticles.com
|
