Transcript IN (2)

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-based 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
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
MGCP (Media Gateway Control Protocol)
Services & Networks
Dr. Amr Talaa
 MGCP is media gateway control protocol, defined by the IE
TF for controlling Telephony Gateways from external call c
ontrol elements called media gateway controllers or call a
gents.
 It allows a media gateway controller or call agent (MGC or
CA) to instruct a media gateway (MG), which converts circu
it switched voice to packet-based traffic, to connect strea
ms coming from outside a packet or cell data network to a
packet or cell stream such as the Real-Time Transport Prot
ocol.
 MGCP is a complementary protocol for both H.323 and SIP,
which was designed as an internal protocol between the Me
dia Gateway Controller and the Media Gateway.
Netw 903 Lecture 2
CS 150 - Fall 2000 - Combinational Logic - 27
MGCP cont’d
Services & Networks
The Call Agent uses MGCP to tell the Media Gateway:
1.
2.
3.
4.
what events should be reported to the Call Agent
how endpoints should be connected together
what signals should be played on endpoints.
MGCP also allows the Call Agent to audit the current
state of endpoints on a Media Gateway.
 The Media Gateway uses MGCP to report events (such
as off-hook, or dialed digits) to the Call Agent.
Dr. Amr Talaa
Netw 903 Lecture 2
28/80
MGCP Connections
Services & Networks
MGCP connections can be point to point or multipoint.
 Point to point connection can be a connection between two
endpoints for transmitting data between these endpoints.
Once the connection is done between two endpoints, data transfer
takes place between the endpoints.
Dr. Amr Talaa
 In a multipoint connection, the connection is set up between an end
point and a multipoint session. In a multipoint connection, connections
can be created over various types of bearer networks.
Netw 903 Lecture 2
29/80
Services & Networks
Dr. Amr Talaa
30/80
Netw 903 Lecture 2
MGCP cont’d
Services & Networks
The MGCP assumes that these call control elements, or Call
Agents, will synchronize with each other to send coherent com
mands to the gateways under their control.
 MGCP does not define a mechanism for synchronizing Call
Agents. MGCP is, in essence, a master/slave protocol, where
the gateways are expected to execute commands sent by the
Call Agents.
Dr. Amr Talaa
Netw 903 Lecture 2
31/80
Softswitch services
Services & Networks
Dr. Amr Talaa
1. Call Waiting
2. Do Not Disturb
3. Call Forwarding (No Answer, Busy Number, Unconditional)
4. Call back
16. Music on Hold
5. Call Hunting
17. Wake-up Call
6. Call forking
18. Message Waiting Indication
7. Voice Mail
19. Anonymous Call Rejection
8. Voicemail 2 Email
20. Access Control Lists - for Inbound a
9. Absent Subscriber
nd Outbound
10. Abbreviated Dialing
21. Call Baring Incoming/Outgoing
11.Dial Emergency
22. Authentication Suspend Subscribe
12.Multiple Subscriber Aliases
r
13.Change of number message
23. ISDN and PSTN test call
14.Feature Activation Prompt
15.Music on Call Waiting
Netw 903 Lecture 2
SoftSwitch Applications
Services & Networks
 Service providers are turning to IP infrastructures to pro
vide practical services to customers while reducing operati
onal costs
 These services can be provided efficiently and cost-eff
ectively using softswitch functionality
• Internet Offload Signaling
• Toll By Bass
• Call centers
Dr. Amr Talaa
 Class4 and Class 5 Services:
Click-to-Dial, Messaging Services, e-Business communi
cation services, value-added services like voice activated
calling, personal directory services.
Netw 903 Lecture 2
Internet Offload Signaling
Services & Networks
 Many LECs (local exchange companies) and ISPs
(Internet service providers) are carrying Internet traffic
over Primary Rate Interface (PRI), or basic subscriber
loops, to gain access to the PSTN and hence their ISP
subscriber.
Dr. Amr Talaa
Netw 903 Lecture 2
Internet Offload Signaling
Services & Networks
 By connecting their Remote Access Server (RAS) to the softswitch,
service providers make use of IMTs, thereby diverting traffic from PRIs
and significantly reducing their access costs.
Dr. Amr Talaa
Netw 903 Lecture 2
Internet Offload Signaling
Services & Networks
 Additionally, facilities-based service providers hosting di
al-up Internet sessions may be experiencing congestion of
switch equipment that was designed for relatively short dur
ation voice calls (average of three minutes), versus the len
gthy sessions of an Internet call (average of 30+ minutes).
 This congestion may result in the need to augment th
e traditional switch with additional port capacity that can
be very costly.
Dr. Amr Talaa
By diverting or offloading the Internet traffic from the traditio
nal switch to the softswitch, the service provider frees up th
e traditional switch to handle more profitable voice traffic.
Netw 903 Lecture 2
Toll By pass
Services & Networks
Toll by pass is the method of using an IP network to ter
minate domestic and international long distance traffic.
Dr. Amr Talaa
 Many Interexchange Carriers (IXCs) are turning to resellers
or service providers of wholesale minutes with private IP netw
orks to terminate these toll calls using the more cost-effectiv
e IP network backbone.
 This application not only reduces the operating costs for t
he IXC but also offers a new stream of revenue for resellers a
nd service providers of IP networks.
 The service provider only needs to connect their RAS or M
G device to the softswitch, to enable terminating traffic to by
pass the PSTN and thereby reduce the cost of terminating th
e calls.
Netw 903 Lecture 2
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
Toll by pass call flow
Services & Networks
Dr. Amr Talaa
1. The individual making a long distance call dials 1+, and the call i
s received by the local LEC’s SSP or Central Office.
2. The switch receiving the call routes it via SS7 to the IXC that wa
s chosen by the end-user customer.
3. The IXC receives the call and launches a call set-up request via
the SS7 network to the reseller that will move the minutes to less ex
pensive IP network.
4. The SS7 network makes the call set-up request: STP to the soft
switch where it is converted to an IP protocol.
5. The softswitch sends a create connection message to the custo
mer’s MG, informing it that there is a call request on a specific trun
k group from the IXC.
6. The MG sends an acknowledgement back to the softswitch to sa
y that everything is okay and it is ready to accept the call.
Netw 903 Lecture 2
CALL Centers
Services & Networks
Dr. Amr Talaa
 call center is a centralized office used for the purpose of r
eceiving and transmitting a large volume of requests by telep
hone.
Automatic Call Distribution systems (ACDs) and Private Bra
nch Exchanges (PBXs) were the main components of call
centers
 Call center systems have progressed to the point that eve
n small companies with as few as 10 agents can get the sam
e powerful call management features as the big players.
 Call centers now are increasingly called " contact centers
" as they incorporate inquires from web and email sources in
addition to phone calls.
 New IP-based call centers depend on Softswitches as swi
tching points and make use of their services
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
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
CTI message exchange
Services & Networks
Dr. Amr Talaa
Netw 903 Lecture 2
NGN call centers services
Services & Networks
Dr. Amr Talaa
FOR THE CUSTOMER
• Call Greeting : System can play recorded voice for greetings to all calls
• Interactive Voice Response : IVR is an interactive answering machine which c
onnects caller with the computer database. IVR gives questions and requests a
nswers. Input data is then processed to provide further information to the caller
. Voice Mail Routed to Agents : Call Centers can give voice mail left by the calle
r to the agent.
• Voice Mail Routed as E-mail : Call Center can send voice mail to the agent lef
t by the caller (it is an IVR advantage). Each agent in charge will get a notificati
on e-mail.
• Web Chat : Customer can get chatting facility. Customer can activate this feat
ure on web page from call center.
• Web Call Back : Customer can contact call center via web to ask an agent to
serve or send information to a telephone number on the web page. System will
then connect an agent and the customer number.
Netw 903 Lecture 2
NGN CALL CENTERS SERVICES
Services & Networks
FOR THE AGENT
• Agent Mobility : Agents don’t have to be concentrated in one room to serve C
ostumer’s need. Agents can be anywhere as long as they are connected with t
elephony devices that have IP Address and connected to the Internet.
• Desktop Statistic Display : Statistic window can be displayed on the agent co
mputer to show information that is shown on the call center display.
• Audio Setting : Each agent has its own audio setting. This audio setting is use
d to distinguish callers that used internet and the caller that use telephone.
Dr. Amr Talaa
• Do Not Disturb : Agent can choose ‘Do Not disturb’ status if he is not availabl
e.
• Audible / Visual Ringing : There is an alert, ring or visual for incoming calls.
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