Comparative analysis of traditional telephone and voice over-internet protocol
1. Comparative Analysis of Traditional
Telephone and Voice-over-Internet
Protocol (VoIP) Systems
Prepared by : Omaima Ismail
2. Introduction
This paper discuss issues should be
taken in consideration when
implementing VoIP.
This study deployed on Carnegie
Mellon University
3. MANAGEMENT ISSUES
This paper explained what is VoIP and
the advantages of using VoIP.
Management issues that concern VoIP
deployment
4. MANAGEMENT ISSUES
Performance (Quality of Service)
Reliability and availability
Scalability
Obsolescence and service life
Regulatory Issues
Electricity Consumption of VoIP Network
Equipment
Backup Equipment, Backup Power and Backup
Phones
Network Traffic and Bandwidth
5. CASE STUDY OF VOIP DEPLOYMENT
Carnegie Mellon University’s (CMU) Computing
Services began investigating IP telephony products
for campus use in Fall 2001, with a goal of utilizing
the existing data network to carry telephone traffic
as well as data.
The study divided into two phases :
first phase was an investigation of the state of IP
telephony technologies and products.
The second phase :starting a trial IP telephony
deployment throughout the Computing Services
division. The majority of the division’s telephones
(90 out of 150 lines) were converted to use the
campus IP network. Fifty lines utilized IP
telephone sets.
6. Network Architecture and
Equipment
Two Cisco CallManager servers operating in a cluster
configuration, one primary server running all services
and one backup.
One Cisco 6509 VoIP Gateway for PSTN connectivity,
with 2 Primary Rate Interfaces (PRIs) – one DID/DOD
PRI, and one Centrex intercom PRI.
VG248 analog gateways are used for connecting Non-
IP telephone users and other analog devices (fax
machines, modems, etc.) to the IP network.
Cisco 7960 IP telephone sets.
Cisco 7940 IP telephone sets.
Existing analog telephone set.
Cisco Catalyst 3524 closet switches
9. Equipment Power
Brand Electronics Model 21-1850/CI power meter
used to measure the electricity consumption of
VoIP network.
The Cisco Catalyst 3524 was metered to be 46 W
with no IP-telephones attached to its ports.
When all 24 ports of the Catalyst 3524 are
connected to IP-telephones, the maximum power
consumed is 325 W.
each additional IP-telephone would cause a linear
increase in power consumption of the Cisco
Catalyst 3524.
11. Estimation of Electricity
Requirements
First scenario assumes a mix of IP
telephones and traditional analog
telephones.
Second scenario assumes a mix of IP-
telephones and existing Meridian digital
telephone sets.
Third scenario presumes that Category 5
cabling has been laid out in all buildings
and all telephones are IP-telephone sets.
12. Estimation of Electricity
Requirements
All the network equipment is assumed to be in
operation 8,760 hours per year and the cost of
electricity is based on an average cost of 5.6 cents
per kWh.
13. Estimation of Electricity
Requirements
Scenarios 1 and 2 require much less
electricity (about 50% less) than scenario 3.
scenarios 1 and 2 do not take into account
the electricity consumption of the Centrex
system at the Verizon Central Office.
Based on current data, the power
consumption of a campus-wide Centrex or
PBX is assumed (constant) at 3 kW.
Adding the electricity consumption of the
Centrex system would increase the total
electricity consumed in scenarios 1 and 2 by
only about $1500 annually.
14. Estimation of Electricity
Requirements
The cost of purchasing new IP-telephones
$300-$400 each.
The cost of installing Category 5 cabling to
enable IP-telephones to be installed in all
offices and buildings are also very high
estimated to be over $10 million over a 2-3
year period.
15. Estimation of Electricity
Requirements
The network backbone electricity
consumption:
VoIP trial of 90 users, the average
instantaneous VoIP traffic based on monthly
traffic, around 0.085 (Mbps)
instantaneous VoIP traffic for the estimated
6,000 users on campus would be estimated
to be around 5.7 Mbps.
This is around 2.6% of the total Internet
network instantaneous traffic on campus,
which is about 220 Mbps.
16. Estimation of Electricity
Requirements
An earlier study on the electricity
consumption of the Internet network
backbone of Carnegie Mellon estimated
that the network backbone at (Cyert Hall)
consumes about 4.2 million kWh annually
Using the VoIP traffic proportion of 2.6%,
the VoIP network would consume about
110,000 kWh of electricity at the Internet
network backbone annually.
17. Backup power
$350,000 was allocated for VoIP backup
power, adopted from a study done by the
University of Oregon for, which was about
the same size as Carnegie Mellon’s.
One Uninterruptible Power Supply (UPS)
per building wiring closet (BWC), so that if
there were a power failure, the UPS would
be able to power the Cisco Catalyst 3524
switches, which in turn power the IP
phones.
19. Outcome of the Trial
Trial was terminated for many reasons:
1. The industry and technology is not yet at the
appropriate standard to compete with the existing
Centrex network.
2. There is not a huge financial win by moving totally
to VoIP.
3. Video-over-IP might be a more convincing reason to
adopt IP technology, but the technology is still in its
infancy.
4. For the case of electricity, deploying VoIP requires
much more electricity than the current Centrex
system due to the additional networking and
telecommunication equipment required for VoIP.
