This document contains a summary of a presentation about protocols including TCP/IP, OSI, and SS7. The summary discusses the key differences between the TCP/IP and OSI models, including the number of layers and how connections are handled. It also provides an overview of the SS7 protocol layers and functions, describing how it is used for signaling in mobile networks and compares it to the OSI model. The document concludes with brief explanations of spectral efficiency and the difference between fading and attenuation in wireless channels.

1. function [op_seq] = pnseq (a, b, c)
Ashwini Patankar
% a : no of fliflops; b = tapp _ function starting c = initial stae
close all;
clc;
x = a;
tap_ff =b;
int_stat= c;
for i = 1:1: length(int_stat)
old_stat(i) = int_stat(i);
gen_pol(i) = tap_ff(i);
end
len = (2 ^x)-1;
gen_pol(i+1)= 1;
gen_l = length(gen_pol);
old_l = length(old_stat);
for i1 = 1: 1:len
% feed back input genration
CellTech V 09.0320
%defining variables
t = 1;
ll = input('lower limit');
for i2 = 1:old_l
if gen_pol(i2)==1 ul = input('upper limit');
stat_str(t) = old_stat(gen_l - i2); st= input('step size');
i2 = i2+1;
fr = ll: st: ul; about set of RULES !
It is all
t = t+1;
x = rand(size(fr)); %defining inpt
%correlation of output
Sequence
%corr_ip = xcorr[x]; % correlation of input
var_c = var(x); %variance of input
corr_op = ifft (psd_op);
%figure(2) trf_flt = 1 ./ (1 + j* 2*pi*fr); %transfer function of the given
subplot(2,2,3) filter
stem(fr,corr_op)
psd_ip = var_c; %power spectral density of input
subplot(2,2,4)
%power spectral density of output
plot(fr,corr_op)
psd_op = ((abs(trf_flt)).^2).*psd_ip; % power spectral density of
cen_op = size(corr_op)
output
mean_sqr = abs(corr_op(1,cen_oopp))
sprintf('E[Y^2 (t)] = %f',mean_sqr)
Friday, March 20, 2009 1
Can be downloaded from http://resources.ashwinipatankar.com/
©2009 Ashwini Patankar

2. Agenda
Protocols – Misconceptions and Reality
TCP/IP Vs OSI
SS7 (The GOD of mobile protocols)
Left Over topics from • (Spectral Efficiency, fading Vs
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3. Protocols
Protocols are a set a rules which define the complex
processes.
Protocol Models defines the services which should be
provided by the layers (TCP/IP model or OSI model)
Protocol Software is the implementation of the
Protocol Model.
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4. TCP/IP
Transmission Control Protocol / Internet Protocol
Story begins in late 1969
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5. TCP/IP Model
Application Layer
Transport Layer
Internet Layer
Network Access Layer
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6. Functions of Layers
•Application Layer Transport Layer
Network Trouble Shooting Flow Control
file transfer Error Control
Remote control
Acknowledgement services for the
internetwork
Internet activities
Interface for the internetwork
Supports APIs
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7. Functions of Layers
•Internet Layer Network Access Layer
Logical Addressing
Interface with the Physical Network
Routing
Formats the Data for transmission
medium
Relates physical address with the
logical address
Error control for data delivered on
physical network
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8. The Data Flow scenario….
Data
Application
Data Header
Transport
Data Header
Internet
Data Header
Network Access
Footer Data Header
1001 010111100001001……..
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9. OSI Model
Open System Interconnection Reference
Model
Development started in 1977 by International
Organization for Standardization
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10. OSI Model
Application
Presentation
Session
TCP IP
Transport
Application Layer
Network Transport Layer
Data Link Internet Layer
Physical Network Access Layer
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11. Functions of Layers
Application Layer
Network interface for applications
Supports application for file transfer , communications etc.
Presentation Layer
Translates data to standard format
Manages encryption and data compression
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12. Functions of Layers
Session Layer
Sessions between communication applications on the communicating
computers
Transport Layer
Error control and Flow control for the internetwork
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13. Functions of Layers
Network Layer
Supports Logical Addressing
Deals with routing related issues
Data Link Layer
Provide interface with the network adapter
Maintains logical links for the subnet
Physical Layer
Converts the data into electric signals
Transmits the data across the transmission medium
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14. TCP/IP vS OSI - Similarities
Share Same Characteristics
Similar Architecture
Share Common Application Layer
Comparable Transport and Network
Layer
Both Models assumed that packet s are
switched
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15. TCP/IP vS OSI – Differences !
OSI TCP/IP
Service, interface and protocol are Protocols in the OSI are
Service, interface
not clearly defined. hidden and can be replaced
and protocol
relatively easily
Because models were invented In this case, the protocols
before protocols, functionalities have been invented before
Functionalities
put in each layer are not very models
optimized.
Seven layers Only four layers.
Numbers of layers
Both are supported in the Only one mode in the
network layer, but only network layer
Connectionless/ connection-oriented (connectionless) but both
Connection-oriented communication in the transport modes in the transport
communication layer. layer are supported, giving
the users a choice.
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16. What is Signaling ?
Signaling refers to the exchange of information between call
components required to provide and maintain service
Out of Band Signaling that does not take place over the same
path as the conversation
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17. Signaling System No. 7 (SS7)
SS7 is used for common channel signaling between
interconnected network
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18. SS7 and OSI
OSI Model SS7 Protocol Model
OMAP ASEs
Application Layer
TCAP
Presentation Layer
ISDN User Part
Session Layer NULL
Transport Layer
SCCP
Network Layer
MTP Level 3
NSP
Data Link Layer MTP Level 2
Physical Layer MTP Level 1
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19. SS7 and OSI
OMAP ASEs
TCAP
OMAP: Operation Maintenance and
ISDN User
Administration Part
Part
ASE: Application Service Element
NULL
TCAP: Transaction Capabilities
Application Part
SCCP: Signaling Connection Control
SCCP
Part
MTP: Message Transfer Part
MTP Level 3 NSP: Network Service Part
NSP
MTP Level 2
MTP Level 1
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20. Functions of Each Part
Network Service Part NSP
Provides ISDN nodes with a highly reliable and efficient means of exchanging
signaling traffic using connection less service
It allows network nodes to communicate throughout the world without concern for
the application or context of the signaling traffic
NSP is made up of four different parts viz., MTP Level 1, 2, 3 and SCCP
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21. MTP
MTP (Message Transfer Part) : it ensures that signaling traffic can be
transferred and delivered between the end – users and the network.
MTP Level 1
MTP Level 2
MTP Level 3
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22. MTP Level 1
Also known as Signaling Data Link Functions
Provides an interface with the actual Physical Channel
# 64 kbps (CCITT)
# 56 kbps (ANSI)
Minimum data rate provided for telephony control operations is
4.8 kbps
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23. MTP Level 2
Also Known as Signaling Link Functions
Provides a reliable link
Message Signal Units (MSUs)
• Variable length packet messages
• Maximum length 272 Octets
• 16 bit cyclic redundancy checksum is included
Flow control, sensing link failure, timer
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24. MTP Level 3
Also known as Signaling Network Functions
• Provides procedures that transfer messages between signaling nodes.
Two types of MTP Level 3 functions
• Signaling message handling
• Signaling network management
Signaling Message Handling
• Routing, distribution and traffic discrimination
Signaling Network Management
• Allows network to reconfigure in case of node failure
• Alternate routing facilities in case of congestion or blocking
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25. SCCP
Signaling connection Control Part
enhancement to the addressing capabilities provided by MTP
• Sub System Numbers (SSNs) based local addressing
• Ability to address global title messages
4 class of services
• 2 connection less ( Class 0 Basic Connection Class and 1 Sequenced –
MTP- Connection Less Class)
• 2 connection oriented (Class 2 and 3)
Four Functional Blocks
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26. SCCP – Class of Services
2
2
Connection
Connection
Oriented
Less Class Class 0 Class 2
Class
Basic Connection Basic Connection
Class Oriented Class
Class 3
Class 1
Sequenced (MTP) Flow control
Connection connection
Oriented Class oriented class
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27. SS7 User Part
Provides call control and management functions
Call set up capabilities to the network
USER part includes:
ISDN User Part (ISUP) , Transaction Capabilities Application Part (TCAP) and
Operations Maintenance and Administration Part (OMAP)
ISUP includes Telephone User Part (TUP) and Data User Part (DUP)
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28. ISUP
Provides signaling functions for carrier
• Supplementary services for Voice, Data and Video in an ISDN environment
Transfer of messages between different exchanges by using MTP
• Routing label (source and destination) Circuit identification code,
• message code to define the format and fucntion of each message
• Have variable lengths , Maximum 272 Octets includes MTP level headers
Some more facilities along with basic bearer services
• User to user signaling, closed user groups, calling line identification, call
forwarding
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29. TCAP & OMAP
TCAP
Transaction Capabilities Application Part
• Refers to application layer
• Concerned with Remote Operations
OMAP
Operation Maintenance and Administration Part
• To ensure trouble free communication is possible
• Supports diagnostics
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30. Signaling traffic in SS7
Maximum Signaling traffic is generated
Call Set Ups
Inter MSCs Handoffs
Location Updates
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31. SS7 Services
TouchStar
• Also known as CLASS
• Switch controlled services (call management capabilities like call block, repeat
dialing, call block, call tracing etc.)
800 Services
• To provide toll free access to the calling party to the services and databases
• Two plans
• 800-NXX first six digits are used to select interexchange carrier (IXC)
• 800 Database Plan call is looked up in database
Alternate Billing and Line Information Database (ADB/LIDB)
• Used CCS network to enable the calling party to bill a call to personal number
from any number
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32. Performance of SS7
Performance of signaling system is studied by connection setup time or end to end
signaling information transfer time
Congestion Control in SS7 Network
Greater Trunking Information
Faster Call Setup
Efficiency Transfer
• High speed • Shorter calls • Additional
signaling setup time information
networks along with
• Less call
signaling traffic
• Smaller delays holding time
• Caller
identification
voice or data
identification
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33. Spectral Efficiency
• For cellular mobile system, Spectral Efficency is
defined as
SUE= (Traffic in Erlang) / (Amount of spectrum in MHz X Area in Sq.
Kms.)
•
•
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34. Fading Vs Attenuation
Fading is the characteristic of Attenuation means decrease
Channel in the strength of the signal
A signal is called as faded only A signal can get attenuated at
when it goes through a any point in the whole
channel transmission system
Fading can cause attenuation but attenuation can not
results in fading
Friday, March 20, 2009 34
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35. function [op_seq] = pnseq (a, b, c)
Ashwini Patankar
% a : no of fliflops; b = tapp _ function starting c = initial stae
close all;
clc;
x = a;
tap_ff =b;
int_stat= c;
for i = 1:1: length(int_stat)
old_stat(i) = int_stat(i);
gen_pol(i) = tap_ff(i);
end
len = (2 ^x)-1;
gen_pol(i+1)= 1;
gen_l = length(gen_pol);
old_l = length(old_stat);
for i1 = 1: 1:len
% feed back input genration
ThAnK YoU !
%defining variables
t = 1;
ll = input('lower limit');
for i2 = 1:old_l
if gen_pol(i2)==1 ul = input('upper limit');
stat_str(t) = old_stat(gen_l - i2); st= input('step size');
i2 = i2+1;
fr = ll: st: ul; QUERRIES ?
t = t+1;
x = rand(size(fr)); %defining inpt
%correlation of output
Sequence
%corr_ip = xcorr[x]; % correlation of input
var_c = var(x); %variance of input
corr_op = ifft (psd_op);
%figure(2) trf_flt = 1 ./ (1 + j* 2*pi*fr); %transfer function of the given
subplot(2,2,3) filter
stem(fr,corr_op)
psd_ip = var_c; %power spectral density of input
subplot(2,2,4)
%power spectral density of output
plot(fr,corr_op)
psd_op = ((abs(trf_flt)).^2).*psd_ip; % power spectral density of
cen_op = size(corr_op)
output
mean_sqr = abs(corr_op(1,cen_oopp))
sprintf('E[Y^2 (t)] = %f',mean_sqr)
Friday, March 20, 2009 35
Can be downloaded from http://resources.ashwinipatankar.com/
©2009 Ashwini Patankar

36. Friday, March 20, 2009 36

37. SCCP – Functional Blocks
Connection
Managemenmt
Oriented
Block
Control Block
Routing Block
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