Transcript Lecture 18 - Electrical and Computer Engineering

Telecommunications Networking
I
Lecture 18
Telecommunications Network
Management
Copyright 1998, S.D. Personick. All Rights Reserved.
Telecommunications Network
Management
• Some questions to ask if you are thinking of
becoming the owner/operator of a large
telecommunications network:
-How do I characterize the quality of service I will
provide in a way that can be measured and
engineered into my networks; and in a way that
my customers will find useful
Copyright 1998, S.D. Personick. All Rights Reserved.
Telecommunications Network
Management
• Some questions to ask if you are thinking of
becoming the owner/operator of a large
telecommunications network:
-How will I ensure that I have enough network
capacity to provide my customers with a specified,
quantifiable quality of service…but not more
network capacity than what is required to do so
Copyright 1998, S.D. Personick. All Rights Reserved.
Telecommunications Network
Management
• Some questions to ask if you are thinking of
becoming the owner/operator of a large
telecommunications network:
-How do I activate services for customers without
having to send technicians out to the customers’
premises (service activation)
-How do I monitor each customer’s quality of
service (service assurance)
Copyright 1998, S.D. Personick. All Rights Reserved.
Telecommunications Network
Management
• Some questions to ask if you are thinking of
becoming the owner/operator of a large
telecommunications network:
-How to I monitor the current state (configuration,
alarm conditions, and usage measurement data) of
my network equipment; and how can my network
automatically recover from various fault
conditions
Copyright 1998, S.D. Personick. All Rights Reserved.
Operations Support Systems
(OSS’s)
• Operations Support Systems (OSS’s), not to be
confused with operating systems, are complex
computer applications which are used to automate
many of the tasks that were done manually, in
telecommunications systems, a few decades ago.
• The objectives are to increase responsiveness to
customers needs, and to reduce cost
• Similar to networked information systems in other
industries
Copyright 1998, S.D. Personick. All Rights Reserved.
Telecommunications
Management Networks (TMN)
Enterprise Management Systems
Service Management Systems
Network Management Systems
Element Management Systems
Security
Billing
Traffic Mgmt/QOS
Connectivity
Redundancy
Routing
...
Network Elements
Copyright 1998, S.D. Personick. All Rights Reserved.
A Classic Traffic Engineering
Problem
Concentrator
1
1
Lines
N
Trunks
M<N
Erlang’s formulas (queuing theory)
Copyright 1998, S.D. Personick. All Rights Reserved.
The Poisson (Random) Process
Events
x
x
Time
x x
x
x
The probability of an “event” in any small
interval of length dt (seconds) is  dt, where “  ” is called
the intensity of the Poisson random process. The occurrence
of “events” in any interval is statistically independent
of the occurrence of “events” in any other disjoint
interval
Copyright 1998, S.D. Personick. All Rights Reserved.
The Poisson (Random) Process
Events
x
x
x x
x
x
The probability of N “events” in an interval of length
T seconds is
 e
N
Where

is

/ N!
T
Copyright 1998, S.D. Personick. All Rights Reserved.
Example
Suppose there are 100 telephone lines connected to a
concentrator with M outgoing trunks. Each telephone
line generates calls (events) approximately as a Poisson
process, at an intensity of 3 calls per hour; and each call
lasts exactly 3 minutes. (Clearly a simplification)
How many outgoing trunks, N, do we need to ensure
the probability of “all trunks busy” at any given time
is less than .01?
“All trunks busy” would occur if we had M or more
“events” in the last 3 minutes
Copyright 1998, S.D. Personick. All Rights Reserved.
Example (Cont’d)
Probability of “all trunks busy” =


M
Where
N 
 e
/ N!
< .01
 =300 x 3/60 = 15
Answer M = 26
Copyright 1998, S.D. Personick. All Rights Reserved.
Service Creation Environment
Non-real-time download
SCE
STP
ISCP (data + call
processing)
Switch
Intelligent Peripheral (IP)
Copyright 1998, S.D. Personick. All Rights Reserved.
Service Creation Example
• Customer
Switch
SCP
IP
off-hook
Prov inst Play announcement # 1
“Please enter you access pin number”
Collect 5 digits
54321#
Authenticate OK
Play announcement # 2
“Please enter the number you are calling, now”
1 215 895 6208
Process call
Call processing
Copyright 1998, S.D. Personick. All Rights Reserved.