Transcript PowerPoint 프레젠테이션 - German University in Cairo

Intelligent Networks
Dr. Eng. Amr T. Abdel-Hamid
Winter 2007
Networks & Services
NETW 903
Intelligent Networks
Services & Networks
SSP
Query
SCP
Response
Dr. Amr Talaa
 a SSP communicating with an SCP to retrieve information
about processing a phone call.
 triggered in different ways, but most often occurs in respo
nse to dialing phone numbers that have special significan
ce; such as:1-800, 19000,…
 The communication between the SSP and the SCP takes p
lace over the SS7 network using the TCAP layer of SS7.
 does not happen for every call but only for those that requ
ire IN services.
Netw 903 Lecture 2
Intelligent Networks
Services & Networks
Dr. Amr Talaa
 The early implementations of IN were based on a databas
e performing number translation
 IN implementations cover a more extensive set of services
from time of day routing plans, follow-me services, pre-p
aid mobile services (wireless intelligent
 networks), calling card services, to advanced network-ba
sed call centre.
 The basic aim of IN is to decouple the service logic from t
he control of the switch fabric. Defined in Q.1201 as ‘‘inte
grated service creation and implementation by means of t
he modularized reusable network functions’’.
 The business aim of IN is the removal of a dependency on
switch manufacturers for the provision of new services.
Netw 903 Lecture 2
Service Data and Logic
Services & Networks
 Service data is the information needed to process a call or
a requested feature. Information such as Called Party Num
ber, Routing Number, and Carrier are examples of service
data.
 Service logic is the decision-making algorithms implement
ed in software that determine how a service is processed.
The service logic acts on service data in making these dec
isions and directing call processing to create the proper c
onnections, perform billing, provide interaction to the subs
criber, and so forth.
Dr. Amr Talaa
Netw 903 Lecture 2
Service Data and Logic
Services & Networks
Dr. Amr Talaa
 Until IN capabilities were introduced in the 1980s, the serv
ice data for the PSTN resided within the telephone switche
s throughout the network.
 The expansion of telecom services created several issues
with this architecture, including the following:
 Increased storage demands
 Maintaining synchronization of replicated data
 Administrative overhead
 One of the benefits of the IN is centralizing service data in
a small number of nodes.
 This alleviates the overhead of administering data at each
switching node and reduces the problem of data synchron
ization to a much smaller number of nodes.
Netw 903 Lecture 2
Service Distribution and Centralization
Services & Networks
SSP
Query
SCP
Response
Query
Dr. Amr Talaa
Response
Adjunct
Netw 903 Lecture 2
Service Distribution and Centralization
Services & Networks
Dr. Amr Talaa
 IN redistributes the service data and logic to other platfor
ms outside of the switch, leaving the switch to perform ba
sic call processing. The SCP and Adjunct are two new no
des that IN has introduced for hosting service data and lo
gic.
 The SCP usually serves a large number of SSPs and maint
ains a large amount of data. It is typically implemented on
larger-scale hardware to meet these needs.
 The Adjunct is a much smaller platform that normally serve
s one or possibly a few local offices and is often co-locat
ed with the switch.
 Adjuncts characteristically use generic hardware platforms
, such as a network server or even personal computers eq
uipped with an Ethernet interface card or SS7 interface ca
rds.
Netw 903 Lecture 2
IN Services
Services & Networks
Dr. Amr Talaa
 There have been two primary drivers
for IN services: regulatory mandates
and revenue-generating features.
 LNP is an example of regulatory ma
ndates that have greatly expanded t
he use of IN.
 Time Of Day (TOD) Routing, and Pri
vate Virtual (PVN) Networking provid
e solutions for everyday business n
eeds are revenue generating service
s providers.
 In Europe, Intelligent Network Applic
ation Part (INAP), developed by the
ETSI standards body, interfaces wit
h ITU TCAP for delivering IN informa
tion between nodes.
 In North America, IN/1 and AIN, dev
eloped by Telcordia, interface with
ANSI TCAP to deliver the equivalent
information.
Netw 903 Lecture 2
AIN
Services & Networks
 A part of the evolution of the original IN concept. AIN is a
term that is primarily used in North America to describe th
e evolution of the IN beyond the IN/1 phase.
 AIN defines a Basic Call State Model (BCSM), which identi
fies the various states of call processing and the points at
which IN processing can occur, Points In Call (PIC) and D
etection Points (DP), respectively.
Dr. Amr Talaa
Netw 903 Lecture 2
Detection Point (DP)
Services & Networks
Dr. Amr Talaa
 DPs between the various PICs represent points at which IN proc
essing can occur. The DP detects that the call has reached a pa
rticular state,
 DP is a generic term that identifies the insertion point for IN pro
cessing. More specifically, each DP is either a Trigger Detection
Point (TDP) or an Event Detection Point (EDP).
 Trigger Detection Point (TDP): TDP is a point at which the SSP c
an set triggers that execute when the TDP is encountered. The tr
igger represents an invocation point for an IN service. When a tri
gger has been subscribed for a particular TDP and the TDP is e
ncountered, the SSP software launches a query to the SCP.
 Event Detection Point (EDP): An EDP is a point at which the SCP
"arms" an event at the SSP. The event is armed to request that t
he SCP be notified when the particular EDP is reached during ca
ll processing. The SCP can then determine how the call should
be further directed. For example, the SCP might want to be notif
ied before a user is connected to a "busy" treatment so that a c
all attempt can be made to another number without the phone u
ser being aware that a busy signal has been encountered.
Netw 903 Lecture 2
Services & Networks
Detection Point (DP)
 PIC is defined as call processing state.
 A set of entry events define the transitional actions that constitute
entering into a PIC.
 Exit events mark the completion of processing by the current PIC.
 Within each PIC, the switch software performs call processing for
that stage of the call in the same processing procedure that exist
ed before the introduction of IN.
PIC
Dr. Amr Talaa
DP
Netw 903 Lecture 2
PIC
Detection Point (DP)
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
Detection Point (DP)
Services & Networks
 Wireline networks have agreed on the IN/AIN triggers for q
uerying databases.
 wireless networks do not necessarily support IN/AIN.
 The industry is looking at IS-41 and GSM protocols for que
rying the LNP database.
 Both the IS-41 and GSM protocols are being modified to s
upport additional parameters for LNP.
 LNP has required new parameters to the ISDN User Part (IS
UP).
Dr. Amr Talaa
Netw 903 Lecture 2
Network Architecture
Services & Networks
Dr. Amr Talaa
 Service Switching Point (SSP): The SSP performs basic call proces
sing and provides trigger and event detection points for IN proces
sing.
 Service Control Point (SCP)/ Adjunct: The SCP stores service data
and executes service logic for incoming messages.
 Intelligent Peripheral (IP): The Intelligent Peripheral (IP) provides sp
ecialized functions for call processing, including speech recogniti
on, prompting for user information, and playing custom announce
ments.
 Service Management System (SMS): Most of the IN services requir
e the management of a significant amount of data. The SMS gene
rally consists of databases that can communicate with IN nodes t
o provide initial data loading and updates.
 Service Creation Environment (SCE): The SCE allows service provi
ders and third-party vendors to create IN services.
Netw 903 Lecture 2
Network Architecture
Services & Networks
Service Creation E
nvironment
Adjunct
SSP
Dr. Amr Talaa
Intelligent
Peripher
Netw 903 Lecture 2
al
SCP
Services & Networks
Intelligent Network Conceptual Model
 The ITU Intelligent Network Conceptual Model (INCM) divide
s the network into different "planes." Each plane shows a p
articular view of the components that make up the IN. The
model is an abstract representation that provides a commo
n framework for vendors and service providers, thereby givi
ng IN architects and implementers a common terminology
base for discussion and allowing the development of modul
ar network components.
Dr. Amr Talaa
Netw 903 Lecture 2
Network Architecture
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
Intelligent Network Conceptual Model
Services & Networks
Dr. Amr Talaa
 Service Plane: Represents a view of the network strictly from the v
iew of the service. The underlying implementation is not visible.
 Global Functional Plane: A view of the common building blocks ac
ross the network that comprise service functions and how they int
eract with Basic Call Processing.
 Distributed Functional Plane: A view of the Functional Entities (FE)
that compose the IN network structure. The DFP is where the coll
ection of SIB implementations represent real actions in the course
of processing actual service functions. The formal term used to d
escribe these functions is Functional Entity Actions (FEA). For ex
ample, this plane describes BCSM within the CCF.
 Physical Plane: Represents the physical view of the equipment an
d protocols that implement the FE that are described in the DFP.
Netw 903 Lecture 2
Intelligent Network Conceptual Model
Services & Networks
Dr. Amr Talaa
 SSP
 Call Control Function (CCF): Provides call processing and swit
ch-based feature control. This includes the setup, maintenanc
e, and takedown of calls in the switching matrix and the local f
eatures that are associated with those calls.
 Call Control Agent Function (CCAF): Provides users with acces
s to the network.
 Service Switching Function (SSF): Provides cross-functional pr
ocessing between the CCF and SCF, such as the detection of t
rigger points for IN processing.
 SCP
 Service Control Function (SCF): Directs call processing based
on Service Logic Programs.
 Service Data Function (SDF): Provides service-related custome
r and network data for access by the SCF during the execution
of service logic.
Netw 903 Lecture 2
Intelligent Network Conceptual Model
Services & Networks
 SMS
 Service Management Function (SMF): Manages the
provisioning and deployment of IN services and se
rvice-related data.
 Service Management Access Function (SMAF): Pro
vides the interface for accessing the SMF.
 SCE
 Service Creation Environment Function (SCEF): Pr
ovides for the creation and validation of new servi
ces. Generates the logic used by the SCF.
 IP
Dr. Amr Talaa
 Specialized Resource Function (SRF): Provides res
ources for end-user interactions, such as recorde
d announcements and user input via keypads, voic
e recognition, and so forth.
Netw 903 Lecture 2
SS7 in the Converged World
Services & Networks
Dr. Amr Talaa
 The "Converged World" of Next Generation Networks (NGN
s) brings with it the promise of voice, video, and data over
a single broadband network.
 This transition from the traditional circuit-switched networ
ks to packet-switched networks has been underway for m
any years, and Voice over IP (VoIP) is now leading the tra
nsition.
 The immediate benefits of NGNs are decreased cost of inf
rastructure and improved ease of management. Longer-te
rm benefits include the ability to rapidly deploy new servic
es.
 Switched Circuit Network (SCN)
Netw 903 Lecture 2
NGN Architecture
Services & Networks
Dr. Amr Talaa
 Media Gateway (MG) handles the media, or bearer, interface. It co
nverts media from the format used in one network to the format re
quired in another network. For example, it can terminate the TDM t
runks from the PSTN, packetize and optionally compress the audi
o signals, and then deliver the packets to the IP network using the
Real Time Protocol (RTP).
 Media Gateway controller (MGC) (also known as a Call Agent) con
tains the call processing. In addition, it manages the resources of
the MGs that it controls.
 Signaling Gateway (SG) sits at the edge of an IP network and term
inates circuit-switched network signaling, such as SS7 or ISDN, fr
om the circuit-switched network. It transports, or backhauls, this
signaling to the MGC or other IP-based application endpoint.
Netw 903 Lecture 2
NGN Architecture
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
Services & Networks
Signaling Transport (SigTran) protocol
Dr. Amr Talaa
 Signaling Transport (SigTran) protocol
defined by RFC 2719 in the 90’s
 The protocol framework identified thre
e necessary components for the SigTr
an protocol stack:
 A set of adaptation layers that supp
ort the primitives of telephony signa
ling protocols
 A common signaling transport proto
col that meets the requirements of t
ransporting telephony signaling
 IP network protocol
Netw 903 Lecture 2
SCTP
Services & Networks
Dr. Amr Talaa
 The Working Group began evaluating the two commonly used tr
ansport protocols, User Datagram Protocol (UDP) and Transport
Control Protocol (TCP) against these requirements.
 UDP was quickly ruled out because it did not meet the basic req
uirements for reliable, in-order transport.
 TCP met the basic requirements, it was found to have several li
mitations, such as:
 Head-of-line blocking: Because TCP delivery is strictly sequ
ential, a single packet loss can cause subsequent packets to
also be delayed. The analysis showed that a 1% packet loss
would cause 9% of the packets being delayed greater than t
he one-way delay time.
 Timer granularity: The retransmission timer is often large (typ
ically one second) and is not tunable.
Netw 903 Lecture 2
SCTP
Services & Networks
 TCP further limitations:
 Also, because of a timer granularity issue and the lack of a
built-in heartbeat mechanism, it takes a long time to detect
failure (such as a network failure) in a TCP connection.
 A new transport protocol, Stream Control Transmission Prot
ocol (SCTP) was developed for transporting SCN signaling.
Note that SCTP is a generic transport that can be used for
other applications equally well.
Dr. Amr Talaa
Netw 903 Lecture 2
SCTP

Services & Networks

RFC 3309 is the most updated version that describes this protoc
ol.
SCTP provides the following features:
Dr. Amr Talaa
Acknowledged error-free, nonduplicated transfer of user data
Data segmentation to conform to path MTU size (dynamically assigned)
Ordered (sequential) delivery of user messages on a per "stream" basis
Option for unordered delivery of user messages
Network-level fault tolerance through the support of multihoming
Explicit indications of application protocol in the user message
Congestion avoidance behavior, similar to TCP
Bundling and fragmenting of user data
Protection against blind denial of service and blind masquerade attacks
Graceful termination of association
Heartbeat mechanism, which provides continuous monitoring of reacha
bility
Netw 903 Lecture 2
SCTP
Services & Networks
 SCTP is a connection-oriented protocol.
 Each end of the connection is a SCTP endpoint. An endp
oint is defined by the SCTP transport address, which cons
ists of one or more IP addresses and an SCTP port. The t
wo endpoints pass state information in an initialization pro
cedure to create an SCTP association.
Dr. Amr Talaa
Netw 903 Lecture 2
SCTP
Services & Networks
 SCTP uses streams as a means of decreasing the impact of hea
d-of-line blocking.
 Streams provide the ability to send separate sequences of order
ed messages that are independent of one another.
Dr. Amr Talaa
Netw 903 Lecture 2
Services & Networks
SCTP
 SCTP provides the ability to have multiple streams within an
association. Each stream provides reliable delivery of order
ed messages that are independent of other streams.
 Packet 2 is dropped again. However, because packets 3, 4,
and 5 belong to a different stream, they can be delivered to
the application without delay.
Dr. Amr Talaa
Netw 903 Lecture 2
User Adaptation (UA) Layers
Services & Networks
 The User Adaptation (UA) layers encapsulate different SC
N signaling protocols for transport over an IP network usin
g SCTP.
 UA layer is unique in terms of the encapsulation because
of the differences of the signaling protocols themselves, f
ollowing are some common features among all UA layers:
Dr. Amr Talaa
 Support for seamless operation of the UA layer peers over an
IP network.
 Support for the primitive interface boundary of the SCN lower
layer, which the UA layer replaces. For example, M2UA supp
orts the primitive interface boundary that MTP Level 2 suppor
ts.
 Support for the management of SCTP associations.
 Support for asynchronous reporting of status changes to lay
er management.
Netw 903 Lecture 2
User Adaptation (UA) Layers
Services & Networks
Dr. Amr Talaa
 MTP Level 3 User Adaptation (M3UA) layer is defined for the t
ransport of SS7 User Part messages (such as ISUP, SCCP, a
nd TUP).
 SCCP User Adaptation (SUA) layer is defined for the transport
of SCCP User Part messages (such as TCAP)
 MTP Level 2 User Adaptation (M2UA) layer is defined for the t
ransport of MTP Level 3 messages.
 MTP Level 2 Peer Adaptation (M2PA) layer is defined for the tr
ansport of MTP Level 3 data messages over SCTP. M2PA effe
ctively replaces MTP Level 2. It provides the ability to create a
n IP-based SS7 link.
 The ISDN User Adaptation (IUA) layer is defined for the transp
ort of Q.931 between an ISDN SG and a MGC.
Netw 903 Lecture 2
UA Common Terminology
Services & Networks

Dr. Amr Talaa
The UAs introduce some new terminology that did not exist i
n the SS7 world.:
 Application Server (AS): A logical entity that serves a spec
ific Routing Key. An example of an Application Server is a
virtual switch element that handles all call processing for
a unique range of PSTN trunks. Another example is a virtu
al database element, handling all HLR transactions for a p
articular SS7 combination. The AS contains a set of one
or more unique ASPs, of which one or more is normally a
ctively processing traffic.
 Application Server Process (ASP): A process instance of a
n Application Server. An ASP serves as an active or backu
p process of an Application Server (for example, part of a
distributed virtual switch or database).
Netw 903 Lecture 2
UA Example
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
Services & Networks
MTP Level 3 User Adaptation
Dr. Amr Talaa
Netw 903 Lecture 2
Services & Networks
SCCP User Adaptation
Dr. Amr Talaa
Netw 903 Lecture 2
Services & Networks
MTP Level 2 User Adaptation

The M2UA protocol defines the layer split between MTP Leve
l 2 and MTP Level 3. M2UA is defined by RFC 3331.
Dr. Amr Talaa
Netw 903 Lecture 2
Services & Networks
MTP Level 2 Peer Adaptation
Dr. Amr Talaa
Netw 903 Lecture 2
Switches and Softswitches
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
Decomposing SSL
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
Call Flow
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
COMPUTER TELEPHONY INTEGRATION
Services & Networks
 Computer telephony integration (CTI) is technology that allows interactio
ns on a telephone and a computer to be integrated or coordinated
 CTI provides the ability to integrate multiple call centers in different physi
cal locations into a single entity
 Functions provided:
Dr. Amr Talaa
• Call information display (caller's number (ANI), number dialed (DNIS), an
d Screen population on answer, with or without using calling line data
• Automatic dialing and computer controlled dialing (fast dial, preview, an
d predictive dial)
• Phone control. (answer, hang up, hold, conference, etc.)
• Coordinated phone and data transfers between two parties (i.e pass on
the Screen pop with the call)
• Call center phone control. (logging on; after-call work notification)
• Advanced functions such as call routing, reporting functions, automatio
n of desktop activities, and multi-channel blending of phone, e-mail, and
web requests
Netw 903 Lecture 2
COMPUTER TELEPHONY INTEGRATION
Services & Networks
 First-Party call control :
• First party call control operates as if there is a direct connection between t
he user's computer and the phone set.
• An example of this would be a modem card in a desktop computer, or a ph
one plugged directly into the computer.
• Only the computer associated with the phone can control the all functions,
by sending command directly to the phone.
Dr. Amr Talaa
 Third-Party call control ( Used in call centers) :
• requires a dedicated telephony server to interface between the telephone n
etwork and the computer network.
• works by sending commands from a user's computer to a telephony server,
which in turn controls the phone centrally.
• Information about a phone call can be displayed on the corresponding co
mputer workstation's screen while instructions to control the phone can be s
ent from the computer to the telephone network
• The user's computer has no direct connection to the phone set and control
led by an external device.
Netw 903 Lecture 2
Softswitches in call centers
Services & Networks
 The combination of CTI and intelligent network services has cre
ated the ability for call centers to route calls across national and in
ternational boundaries transparent to the caller
 In Call centers, CTI and Database Servers are used in addition t
o PBX/ACD
 ACDS communicate with softswtiches to enhance call routing fr
om callers
outside the IP network
Dr. Amr Talaa
 The use of CTI(Computer Telephone Integration) will allow the IV
R system to look up the CLI (Calling Line ID) on a network databas
e and identify the caller and provide the required service
Netw 903 Lecture 2
Presence center architecture
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
interactive voice response
Services & Networks
Dr. Amr Talaa
Interactive voice response, or IVR, is a phone technology that al
lows a computer to detect voice and touch tones using a norm
al phone call.
• Call centers use IVR systems to identify and segment callers.
• The ability to identify customers allows the ability to tailor serv
ices according to the customer profile.
• It also allows the option of choosing automated services.
• Information can be fed to the caller allowing choices such as:
wait in the queue, choose an automated service, or request a c
allback.
• The use of CTI(Computer Telephone Integration) will allow the
IVR system to look up the CLI (Calling Line ID) on a network dat
abase and identify the caller.
Netw 903 Lecture 2
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
CTI message exchange
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2