Local Number Portability
Traffic Analysis Calculations
ENGR 475 – Telecommunications
October 19, 2006
Harding University
Jonathan White
Outline - LNP
 Definition

of Local Number Portability
Required by Law
 New
components in the network
 Why have LNP
 Wireless and LNP
 911 and LNP
Outline – Traffic Analysis
 What
Traffic Engineering is used for
 Busy Hour traffic
 A.K. Erlang’s Distributions
 Examples of board
Local Number Portability
 LNP


–
Mandated by the Telecommunications Act of
1996.
Telcos had until 2002 to completely comply.
 What


it is:
Consumers can keep their telephone number
and have any provider that will serve them.
Consumers can also keep their telephone
number when they move to a new location.
Benefits of LNP
 More
competition drives lower prices and
better service.

Telecommunications biggest enemies:
• Churn
• Fraud
 Most
people want to keep their telephone
numbers.

Why would this be true?
 The
LNP act gives these people the ability
to have competition for their dollars.
Wireless LNP
 Because
of LNP, you can get a local
telephone number any where in the US,
no matter where you live.

For example, I bought my phone in
Bentonville, Arkansas, but I was able to get a
local Searcy number.
 However,
having wireless LNP makes
billing even more complex.
Additional Network Objects

On the SS7 network, a new database is required
to support LNP so that the call is routed across
the correct network.

Providers can actually pay to have access to updated
LNP databases.
• GTE and Cincinnati Bell Information Services

This adds cost and delay to the system.
 This database is called the local service
management system.

Local SMS.
911 and LNP
 The
911 system used to derive location
information based on your telephone
number.

No longer directly possible.
 Your
location information is now passed to
911 through database access.
 This makes the 911 system less reliable.
911 and Wireless
 Cell
phone towers are no equipped with
GPS units so that they can calculate
where your call came from.

If 3 or more towers are within your signal
range, they can triangulate your exact
location.
 But
again, LNP means 1 more database
dip.

Also, the databases must be maintained.
Who Pays
 We
ultimately pay for local number
portability.
 Is it worth it?
Traffic Analysis
 Method
for determining the cost
effectiveness of various sizes and
configurations of networks.
 Helps us to decide how many telephone
trunks we should use to service
organizations.
 Formulas were used; now, computer
modeling is almost exclusively used.
Uses of Traffic Engineering
 Utilizing
the correct number of links at the
best price point.

Cost versus effectiveness
 What



do you engineer to?
The busiest hour?
The average amount of traffic?
The minimum required that will still retain
customers?
 How
are our road systems engineered?
Agner Krarup Erlang


Danish mathematician and engineer.

1878 – 1929
Worked for the telephone
company in Copenhagen from
1908 to 1929.
 Applied math to calculating
how many circuits and
telephone operators were
needed.
 His formulas were incredibly
good for the time period, and
they were used until very
recently.
Grade of Service
– How many callers will be refused
service.
 GOS

This could be a busy tone or a redirection to
voice mail.
 Telephone
companies have designed their
networks so that the probability that a
circuit will be blocked must be between 1
and 5 percent.

To get a lower blocking percentage than 1
percent gets exponentially more difficult.
Traffic Analysis
 Erlang’s





ideas are used extensively in:
Data networks
Voice networks
Busy hour traffic on interstates
Banking/Supermarket queuing theory.
General max/min optimization problems
Traffic Analysis
 The
rest is on the board