> What FunctionalityIs Gained, Degraded, or Enhanced on VoIP Networks?

What Functionality
Is Gained, Degraded, or
Enhanced on VoIP Networks?
With every introduction of a new technology come original and improved features
as well as untested problems. Several key differences in functionality are gained, lost,
and enhanced between IP-enabled voice networks and traditional PSTN networks.
Gained Functionality
Two of the biggest advantages of VoIP technology are reduced costs and increased
mobility.
Cost Savings
VoIP saves you money.VoIP reduces or in most cases eliminates your company’s toll
charges and government imposed taxes on your telephone companies that must be
paid with the use of traditional voice network. By using your existing data network
lines, which in most cases are underutilized by just carrying data for your voice
traffic, you eliminate most of your toll charges. Further, you eliminate expensive
hardware maintenance and the cable wiring charges of traditional phone equipment
by consolidating your data and voice networks.
Mobility
VoIP allows greater mobility. Routing your DID number to a dynamic IP address
allows you to take your phone number anywhere where you go. All your office phone
functionality, such as local extension calling, is transferred with your movement.
Wiring and Scalability
Traditional phones in your office require direct connection into the PBX system and
separate port allocation.With VoIP-enabled phones and PBX, you can plug into the
same data-jack port as your desktop-PC and begin communicating with your PBX
system. By using an already existing data port, you eliminate the need for extra
phone ports and increase scalability with inexpensive LAN switches.
Open Standards
Open standards and multivendor interoperability that exists in VoIP compared with
traditional proprietary phone companies’ technology allows businesses and service
providers to purchase hardware and phone services from multiple vendors without
being dependent on one platform, one company. Open standards allows technology
to grow and be developed by the community at large, leading to better functionality
in the overall product.
Rich-Media Conferencing
Rich-media conferencing combines voice, video, and data. By combining the three
together, participants can share presentation documents and observe each other’s facial
expressions, thus increasing productivity and the contribution of each participant.
Combined Functionality at Contact Centers
IP-based contact center solutions allow operators to support multiple integrated
ways of communication over a single physical connection. Inbound and outbound
calls can be integrated with live chat, web collaboration, and other applications,
increasing an agent’s productivity and caller support over single data line.


Degraded Functionality
With emerging technologies come new potential issues, which can be resolved only
over time by trial and error.VoIP introduces potential degraded functionality for voice
quality.The most important functionality in voice is the voice itself. It is important to
hear the other party on the other end loud and clear. By using a single network for
combined video, data, and voice communication, your core voice quality may be
degraded by competing resources. Unlike in traditional PSTN circuit-switched networks,
where dedicated channels are opened for each voice call,VoIP packet-routed
network shares its channel resources between multiple applications.
Coder-Decoder codec is used to digitize analog voice. Codec has many different
selections. Some codecs are highly rated such as the G.711 at 64Kbps for their
speech quality but pay for higher bandwidth usage. Other codecs such as G.729 at
8Kbps offer equally good speech quality at less bandwidth usage but require higher
processing power. Different codec samplers are used to encode signals into a more
efficient form of transmission and are key components for the quality of voice.
Quality of Service (QoS) is a major issue in VoIP networks. When using a publicly
available network such as the Internet to transfer calls, it is not easy to guarantee
QoS.Three major concerns to consider when using the Internet for voice calls and
QoS are:
■ Latency Delay for packet delivery, accepted latency for voice in IP networks
is less than 150ms (one way)
■ Jitter Variations in delay of voice packet delivered
■ Packet Loss Packets are dropped, most likely due to congestion in network
There is very little chance when you experience latency over the Internet
greater than 150ms unless your own private links are saturated or you are trying to
route overseas internationally or by satellite. Service level agreements (SLAs) can be
negotiated with service providers to ensure your latency, jitter, or packet loss does
not adversely affect your company’s voice calling.
911
Emergency 911 service has been built for traditional circuit switched networks and
does not integrate well with VoIP providers.VoIP providers implement E911
(Enhanced 911) that routes 911 calls over a user data link to PSTN 911 service.
FCC has mandated E911 for VoIP providers, but carriers are still struggling with
implementation and interconnection agreements.We discuss E911 service and its
details later in Chapter 15. If your data link is down, you will lose connectivity to
your 911 operator. Many VoIP service providers have agreements that each user
must sign prior to the initiation of service. Many traditional phones will still allow
you to call 911 even though your service has been disconnected. It is a good idea to
keep an old phone line around connected to PSTN for 911 service in case an emergency
occurs while your data link is down.


Enhanced Functionality
VoIP can provide redundancy to traditional PSTN networks.A company can have
all its calls routed using a cost-effective VoIP solution and still have the ability to
reroute calls over the PSTN during emergencies when the data network might
be down.
Security for IP-enabled networks is both enhanced and in some cases degraded
by VoIP. Making calls via VoIP allows you to encrypt each phone call, preventing
eavesdropping, unlike over PSTN where calls are usually made in the clear. On the
other hand, end-user phones and telephone equipment is now IP-enabled, which
allows connectivity and attacks to come over the Internet if not protected. Viruses
now have a way of connecting and potentially affecting your phone systems.