© Ole Brun MadsenVANS1 VALUE Added Services Ole Brun Madsen Professor Department of Control...

© Ole Brun Madsen VANS 1

VALUE Added Services

Ole Brun MadsenProfessor

Department of Control EngineeringAalborg University

Integrated Services Digital Network, ISDN & SS7 Voice over IP, VoIP

VAS, VAN, VANS, EDI, EC, EFT


ISDN



Integrated Services Digital Network


Integrated Services Digital Network (ISDN)

Integrated Services Digital Network (ISDN) is comprised of digital telephony and data-transport services offered by regional telephone carriers.

ISDN involves the digitalisation of the telephone network, which permits voice, data, text, graphics, music, video, and other source material to be transmitted over existing telephone.

ISDN represents an effort to standardise subscriber services, user/network interfaces, network and internetwork capabilities.

ISDN applications include high-speed image applications (such as Group IV facsimile), additional telephone lines in homes, to serve the telecommuting industry, high-speed file transfer, and video conferencing. Voice service is also an application for ISDN.


CP CO

Access Network

ISDNSwitch

R

NT1NT2TA

NT1NT2

NT1NT2

S T U

ISDN Reference points


ISDN Reference points

ISDN specifies a number of Reference Points that define logical interfaces between functional groupings, such as Terminal adapters (TA) and Network Termination points (NTx).

ISDN reference points include the following:

• R—The reference point between non-ISDN equipment and a TA.• S—The reference point between user terminals and the NT2.• T—The reference point between NT1 and NT2 devices.• U—The reference point between the ISDN Switch and NT1 devices.


ISDN Interfaces

The ISDN Basic Rate Interface service (I.430) offers two B channels and one D channel (2B+D).

The Basic Rate B-channel service operates at 64 kbps and is meant to carry user data.

The Basic Rate D-channel service operates at 16 kbps and is meant to carry control and signalling information, although it can support user data transmission under certain circumstances. The D channel signalling protocol correspond to the OSI reference model Layers 1-3.

The Basic Rate Interface also provides for framing control and other overhead, bringing its total bit rate to 192 kbps.

The ISDN Primary Rate Interface service (I.431) offers 30 B channels plus one 64-Kbps D channel and a total interface rate of 2.048 Mbps. (30B+D)


ISDN User Signalling Protocols

The ISDN signalling protocols are used across the D channel to ensure the control and signalling information flow. A variety of call-establishment, call-termination, information, and miscellaneous messages are specified, including: SETUP, CONNECT, RELEASE, USER INFORMATION, CANCEL, STATUS, and DISCONNECT.

Standards:ISDN user-network interfaces (I.410 - I.414) Application of I-series Recommendations to ISDN user-network interfaces (I.420 - I.421) Layer 1 Recommendations (I.430 - I.432.5) Layer 2 Recommendations (I.440 - I.441) Layer 3 Recommendations (I.450 - I.452) Data link layer (Q.920 - Q.923) Network layer (Q.930 - Q.939) User-network management (Q.940 - Q.941)


ISDN services are divided into three groups:

A Bearer service, which describes the network transmission characteristics offered by the network operator at the interfaces between customer terminal and network.

A Teleservice, which defines the necessary characteristics of the terminals, above and beyond the transmission characteristics of the network, for compatibility checking when information is presented.

An ISDN Value Added Service, which is described as a Supplementary Service when it is invoked in conjunction with one of the two basic services.

A basic service is a combination of a bearer service and a teleservice.

A supplementary service is a service which provides additional features to a basic service and is always used in association with a basic service.

ISDN Services


ISDN Bearer services provide the user with the possibility of gaining access to various forms of communication offered by the network. They ensure the successful setting-up, selection, supervision and disconnection of a circuit between terminals.

Bearer service information sent by the Customer Premises Equipment (CPE), provides an indication by means of bearer capability, transfer mode, transfer rate and transfer capability information, to the routing features of the exchange as to what transmission medium or signalling method is required between exchanges when initialising a connection.

If additional information is required by CPE, to ensure compatibility between the calling and called terminals, the calling CPE includes the Low Layer Compatibility (LLC) information. LLC contains similar information and has the same coding as the bearer capability. The LLC is transferred transparently by the network to the called CPE for the terminal compatibility set-up, whereas bearer capability is used by the network for routing purposes.

ISDN Bearer Services


ISDN Bearer Services

ISDN offers bearer services in the following two modes:

Circuit switching

64 kbit/s unrestricted (which can be used for video telephony,video conference, fax Gr.4, text and data transfer, etc.)

speech (which can be used for high quality telephony);

3,1 kHz Audio (which can be used for normal telephony, fax Gr.3 and analogue modem calls).

Packet switching - For possible future release


ISDN Teleservices

ISDN Teleservices offer the user the option of accessing to various forms of applications. High layer Compatibility (HLC) information sent by CPE enables CPE to distinguish between various teleservices, namely -

• telephony• fax group 2/3• fax group 4• telefax• videotex • MHS (Message Handling System) • 7 kHz telephony • videotelephony.


ISDN Supplementary Services

The following ISDN supplementary services will be available in association with circuit-switched connections.

Calling line identification presentation (CLIP) - The CLIP service provides the called user with the possibility of receiving the identification of the calling user. The identification is not always possible, e.g. when the calling user does not allow the presentation of his number, or in case of interworking with other networks.

Calling line identification restriction (CLIR) - The CLIR service enables the calling user to restrict presentation of its ISDN number at the called user. The invocation of the restriction is done on a call-by-call basis. Permanent restriction is possible on a subscription basis.


Multiple subscriber numbers (MSN) - The MSN services provides the facility to assigning multiple numbers (not necessarily consecutive) to a single basic access (Basic Rate). This enables the selection of one or multiple distinct terminals attached to the same access. The MSN services is only possible on a Basic Access in a point-to-multipoint configuration (passive bus). A maximum of eight numbers is allowed on the same access. This feature is available to ISDN customers on Basic Rate only.

Direct dialling in (DDI) - The DDI service enables a user to call a user on a private ISDN directly via the public ISDN, by using a public ISDN numbering plan. The DDI number is used by the private ISDN to progress the call to the destination user

The DDI service is possible on Basic and Primary Rate accesses in a point-to-point configuration.

ISDN Supplementary Services (continued)


Terminal portability (TP) - The TP supplementary service provides users with the possibility of moving a CPE terminal from one S,-bus socket to another within one given Basic Access during the active state of a call, by suspending and resuming the call for a limited period of time. This feature is available to ISDN customers on Basic Rate only.

Advice of charge (AOC-E) - AOC-E provides the calling party with charging information. The tariff information presented will be the total charge at the end of the call.

Call waiting (CW) - The CW supplementary service provides an user with the option of being notified of another incoming call when all B-channels are in use. The user has the option to accept, reject or ignore the call within a limited period of time. This feature is available to ISDN customers on Basic Rate only.



Call hold (CH) - The CH supplementary service allows the user to put a call on hold ore to make or answer another call and at any stage resume the original call. This feature is available to ISDN customers on Basic Rate only.

Call forwarding, unconditional (CFU) - The CFU supplementary service permits the served user to have the exchange forward all incoming calls to the forwarded-to number.

Call forwarding, busy (CFB) - The CFB supplementary service permits the forwarding of incoming calls (all calls or specific calls only ) to another number if a busy condition is returned to the calling user. This feature is available to ISDN customers on Basic Rate only.

Call forwarding, no reply (CFNR) - The CFNR supplementary service permits the forwarding of incoming calls (all calls or specific calls only) to another number, if the incoming call is unanswered. This feature is available to ISDN customers on Basic Rate only.



Sub addressing (SUB) - The SUB supplementary service permits the called user to expand his addressing capacity beyond the one given by the ISDN number. The sub-addressing information is transparently transported by the network from the calling to the called user and can be used for multi-application selection on CPE.

Closed User Group (CUG) - The supplementary service CUG provides users with the possibility of forming groups, to and from access, which are restricted. A specific user may be a member of one or more CUG'S. Members of a specific CUG can communicate among themselves, but not, in general, with users outside the group. CUG members can have additional capabilities that allow them to originate calls outside the group, and/or to receive calls from outside the group.

User to user signalling 1 (UUS1) - The UUS1 supplementary service allows an ISDN user to send/receive a limited amount of information to/from another ISDN user over the signalling channel during the set-up and clearing phases of a call with the UUSl information embedded within the call control messages.



Common Channel Signalling System No. 7 SS7

ISDN/SS7




Common Channel Signalling System No. 7 (SS7)

SS7 is a global standard for telecommunications defined by ITU (ITU-T).

The standard defines the procedures and protocol by which network elements in the public switched telephone network (PSTN) exchange information over a digital signalling network to effect wireless (cellular) and wireline call set-up, routing and control.


SS7, Standards

General (Q.700 - Q.700) Message transfer part (MTP) (Q.701 - Q.709) Specifications of Signalling System No. 7 (Q.710 - Q.710) Signalling connection control part (SCCP) (Q.711 - Q.716) Telephone user part (TUP) (Q.721 - Q.725) ISDN supplementary services (Q.730 - Q.737.1) Data user part (Q.741 - Q.741) Signalling System No. 7 management (Q.750 - Q.756) ISDN user part (Q.761 - Q.768) Transaction capabilities application part (Q.771 - Q.775) Test specification (Q.780 - Q.788) Q3 interface (Q.811 - Q.835) General (Q.850 - Q.850) Data link layer (Q.920 - Q.923) Network layer (Q.930 - Q.939) User-network management (Q.940 - Q.941)

Intelligent Network (Q.1200 - Q.1711)


SS7

Signalling Links

SS7 messages are exchanged between network elements over 64 kbps bi-directional channels called signalling links. Signalling occurs out-of-band on dedicated channels rather than in-band on voice channels.

Signalling Points

Each signalling point in the SS7 network is uniquely identified by a numeric point code. Point codes are carried in signalling messages exchanged between signalling points to identify the source and destination of each message.

There are three kinds of signalling points in the SS7 network

• Service Switching Point (SSP) • Signal Transfer Point (STP) • Service Control Point (SCP)


SS7 Signalling Points

Service Switching Point (SSP) are switches that originate or terminate calls. An SSP sends signalling messages to other SSP's to set-up, manage, and release voice circuits required to complete a call. Network traffic between signalling points may be routed via a Signal Transfer Point (STP). An STP routes each incoming message to an outgoing signalling link based on routing information contained in the SS7 message.

An STP may perform global title translation, a procedure by which the destination signalling point is determined from digits present in the signalling message

An STP can also act as a "firewall" to screen SS7 messages exchanged with other networks.


An SSP may also send a query message to a Service Control Point (SCP) acting as a centralised database to determine how to route a call.

An SCP sends a response to the originating SSP containing the routing number(s) associated with the dialled number. An alternate routing number may be used by the SSP if the primary number is busy or the call is unanswered within a specified time. Actual call features vary from network to network and from service to service.

Because the SS7 network is critical to call processing, SCP's and STP's are usually deployed in mated pair configurations in separate physical locations to ensure network-wide service in the event of an failure. Links between signalling points are also provisioned in pairs. Traffic is shared across all links in the linkset. If one of the links fails, the signalling traffic is re-routed over another link in the linkset.

The SS7 protocol provides both error correction and retransmission capabilities to allow continued service in the event of signalling point or link failures.

SS7 Signalling Points


The SS7 protocol stack

ISUP

MTP Level 1

MTP Level 2

MTP Level 3

SSCP

TCAP

Application OMAP

TUP DUP

MAP

HLR VLR

EIR AUC

INAP

IN

OSI-level

Presentation

Session

Transport

Network

Link

Physical

ASE


The Message Transfer Part (MTP)

MTP Level 1 (Q.702) defines the physical, electrical, and functional characteristics of the digital signalling link. Physical interfaces defined includes single 64 kbps channels or 32*64 kbps channels.

MTP Level 2 (Q.703) ensures end-to-end transmission of a message across a signalling link, including flow control, message sequence validation, retransmission and error checking.

MTP Level 3 (Q.704) provides network wide message routing between signalling points in the SS7 network and is able to handle re-routing in case of link-failure and signalling points out of order.

ISUP

MTP Level 1

MTP Level 2

MTP Level 3

TCAP

OMAP

TUP DUP

MAPINAPASE

SSCP

The Message Transfer Part (MTP) is equivalent to the OSI Layer 1-3


The ISDN User Part (ISUP) (Q.763) defines the protocol used to set-up, manage, and release trunk circuits that carry voice and data between terminating line exchanges (e.g., between a calling party and a called party).

ISUP is used for both ISDN and non-ISDN calls. However, calls that originate and terminate at the same switch do not use ISUP signalling.

The Telephone User Part (TUP) (Q.723) handles analogue circuits only. ISUP has replaced TUP in most countries

ISUP, TUP

MTP Level 1

MTP Level 2

MTP Level 3

TCAP

OMAP

DUP

MAPINAPASE

ISUPTUP

SSCP


DUP

The Data User Part (DUP) (X.61, Q.741) defines the necessary call control, and facility registration and cancellation related elements for international common channel signalling by use of SS7 for circuit-switched data transmission services. The data signalling messages are divided into two categories:

Call and circuit related messages, used to set up and clear a call or control and supervise the circuit state.

Facility registration and cancellation related messages, used to exchange information between originating and destination exchanges to register and cancel information related to user facilities.

MTP Level 1

MTP Level 2

MTP Level 3

TCAP

OMAP MAPINAPASE

ISUPTUP

SSCP

DUP


SCCP

The Signalling Connection Control Part (SCCP) (Q.713) provides connectionless and connection-oriented network services and global title translation (GTT) capabilities.

A global title is an address which is translated by SCCP into a destination point code and subsystem number. A subsystem number uniquely identifies an application at the destination signalling point. SCCP is used as the transport layer for TCAP-based services.

MTP Level 1

MTP Level 2

MTP Level 3

TCAP

OMAP

DUP

MAPINAPASE

ISUPTUP

SSCP


Transaction Capabilities Applications Part (TCAP)

Queries and responses sent between SSP's and SCP's are carried in TCAP messages. For example, an SSP sends a TCAP query to determine the routing number associated with service 800 or service 900 numbers and to check the personal identification number (PIN) of a calling card user.

In mobile networks TCAP carries Mobile Application Part (MAP) messages sent between mobile switches and databases to support user authentication, equipment identification, and roaming.

MTP Level 1

MTP Level 2

MTP Level 3

OMAP

DUP

MAPINAPASE

ISUPTUP

SSCP

TCAP

The Transaction Capabilities Applications Part (TCAP) (Q.773) supports the exchange of non-circuit related data between applications across the SS7 network using the SCCP connectionless service.


Mobile Application Part (MAP)

In mobile networks (GSM) when a mobile subscriber roams into a new mobile switching centre (MSC) area, the integrated visitor location register requests service profile information from the subscriber's home location register (HLR) using MAP (mobile application part) information carried within TCAP messages.

ISUP

MTP Level 1

MTP Level 2

MTP Level 3

TCAP

OMAP

TUP DUP

MAP

HLR VLR

EIR AUC

INAP

IN

ASE

SSCP

The Mobile Application Part (MAP) handles messages sent between mobile switches and databases to support user authen-tication, equipment identification, and roaming are carried by TCAP.


INAP

The Intelligent Network Application Part (INAP) is the application protocol for IN services.

ISUP

MTP Level 1

MTP Level 2

MTP Level 3

TCAP

OMAP

TUP DUP

MAP

HLR VLR

EIR AUC

INAP

IN

ASE

SSCP


Voice over IP



VoIP


Voice over IP (VoIP)

IP telephony switches enable voice calls to be made within Internet Protocol (IP) networks, such as the public Internet or the private IP network of a large organisation, and between IP networks and the Public Switched Telephone Network (PSTN).

Calls can be made between IP network terminals, between PSTN telephones and IP terminals, or between PSTN telephones across an IP network.

To inter-operate with the PSTN, an IP telephony switch must support the Signalling System 7 (SS7) protocol, either on-board or via an off-board interworking device. SS7 is used to efficiently set up calls in the PSTN and to query PSTN database servers.

The support of SS7 by IP telephony switches represents an important step in the integration of the PSTN and IP data networks.


The IP-Telephony Switch

Internet PSTN

IP-TelephonySwitch

IP-Gate keeper

Telephony Gateway

IP-TelephonySwitch

IP-Gate keeper

Telephony GatewayPSTN


Voice over Internet Protocol (VoIP)

H.323 H.323

IP-TelephonySwitch

IP-TelephonySwitch

PSTN PSTN

Internet Internet



H.323 H.323

IP-TelephonySwitch

IP-TelephonySwitch

PSTN PSTN

Internet Internet


The TIPHON projet, ETSI work on Voice over IP

Recognizing the urgent need for common solutions, ETSI, has established the project TIPHON (Telecommunications and Internet Protocol Harmonization Over Networks).

The project's objective is to support the market for voice communication and related voiceband communication (such as facsimile) between users. It will ensure that users connected to IP based networks can intercommunicate with users in Switched Circuit Networks (SCN - such as PSTN, ISDN and GSM.

The support comes in the production of appropriate ETSI technical specifications and reports. In addition, the activity will include validation and demonstrations, in order to confirm the appropriateness of the solutions proposed.

Given the universal nature of IP networks, the prime goal is to produce global standards. As ETSI is essentially a European body, it recognizes that co-operation with relevant groupings in ITU-T and IETF is essential.


The TIPHON project, ETSI work on Voice over IP

Home GatekeeperIP-addr: 172.27.0.1

IP-terminal:phone-#:+999-123456789012IP-address: 172.27.4.134

phoneswitch

Gateway

Router

Gatekeeper

dial: +999-123456789012

“Black Box”: E.164 / IP Resolution

123456789012 - 172.27.0.1 … ...

Phone Network IP-network

1)2)

3)

4)


H.323

In 1996, ITU ratified the H.323 specification which defines how delay-sensitive voice and video traffic is transported over local area networks. In 1998 ITU approved the H.323 Revision 2 for use in wide area networks.

Operating H.323 terminals over a wide area network may result in poor performance due to the lack of quality-of-service (QoS) guarantees in e.q. IP networks.

In the Internet, congestion due to inadequate bandwidth often leads to long delays in the delivery of time-sensitive packets. For voice data packets which are lost or discarded result in gaps, silence, and clipping in real-time audio playback.

To support a real-time QoS, the Internet Engineering Task Force (IETF) has proposed a new IP-based protocol called the Resource Reservation Protocol (RSVP). Using RSVP, both real time and non-real time applications can specify an appropriate QoS over the shared bandwidth of the Internet. (For more information, refer to RFC 1633.)


ITU Series H: Audiovisual and multimedia systems

Systems and terminal equipment for audiovisual services

H.310 (11/96) Broadband audiovisual communication systems and terminalsH.310 Corr.1 (2/98)

H.320 (7/97) Narrow-band visual telephone systems and terminal equipment

H.321 (2/98) Adaptation of H.320 visual telephone terminals to B-ISDN environments

H.322 (3/96) Visual telephone systems and terminal equipment for local area networkswhich provide a guaranteed quality of service

H.323 (2/98) Packet based multimedia communications systems

H.324 (2/98) Terminal for low bit-rate multimedia communication


H.323

H.323 entities may be used in point-to-point, multipoint, or broadcast (as described in Recommendation H.332) configurations. They may interwork with H.310 terminals on B-ISDN, H.320 terminals on N-ISDN, H.321 terminals on B-ISDN, H.322 terminals on Guaranteed Quality of Service LANs, H.324 terminals on GSTN and wireless networks, V.70 terminals on GSTN, and voice terminals on GSTN or ISDN through the use of Gateways.

H.323 entities may be integrated into personal computers or implemented in stand-alone devices such as videotelephones.


VoIP

ISDN 30B+D

IP Router

IP RAS

PSTNswitch

IP DAS

SDHDXC

ATMSwitch

IP Tlf

Acc

ess

Net

wor

k

Tra

nsp

ort

Net

wor

k

IN

IP-IN


VAS, VAN, VANS, EDI, EC, EFT



Value Added Services


A Value Added Network (VAN) provides a set of Value Added Network Services (VANS) on top of ordinary telecommunication network to facilitate the interconnection and interworking in electronic based trade.

The term has mostly been connected with Electronic Mail (EM),Information Databases (IDB), Electronic Data Interchange (EDI), Electronic Commerce (EC) and Electronic Funds Transfer (EFT).

Part of the work taken care of by the VAN providers is becoming standard services in the global telecommunication networks.

The role of the VAN providers is an important element in the Global Information Infrastructure (GII)

VAN, VANS


VANS, Network Features

The roles of a VAN can be outlined as follows:

End-to-end Communications capability round the clock across one or more telecommunication networks. Communications management

Password managementAccess managementStatus monitoring, BroadcastAccountingetc.

Clearing house for EC and EFT.Translation capabilities from one EDI format to another;Host of complementary services, such as Mailbox services, EM, EFT, IDB etcTechnical support in EDI, EC and EFT applications.


Electronic Data Interchange (EDI)

EDI is the application to application transfer of business documents between computers. The transfer requires that the sender and receiver agree upon a standard document format for the document to be transmitted.

EDI is a new fast, inexpensive, and safe method of doing business by sending purchase orders, invoices, shipping notices, receiving advises, and other frequently used business documents.

EDI EDI


Electronic Funds Transfer (EFT)

EDI can also be used to transmit financial information and payment in electronic form referred to as Financial EDI or Electronic Funds Transfer (EFT).

The label EFT encompasses any monetary transaction that is completed by electronic means like Automated Teller Machine (ATM) transactions, wire transfers, point of sale (POS) transactions, tape exchange of financial data and computer- to-computer electronic exchange of business documents such as purchase orders and shipping notices between business partners, in a computer readable format (EDI).


EDI, EFT

The buyer sends their EDI Purchase Orders to a VANS provider, who proceeds to route the orders to the appropriate suppliers electronic mailbox. The supplier connects to the VAN and to their mailbox, and receive the orders from their buyers.

The same scenario is followed when the supplier sends an EDI Invoice to the retailer. VANs also provide verification and confirmation of the transaction, ensuring security and quality control of the data processed.

EDI/EFT EDI/EFTEDI/EFT

VAN

In a typical EDI scenario, suppliers and retailers exchange purchase orders and invoices electronically from computer to computer through a VANS provider.

© Ole Brun MadsenVANS1 VALUE Added Services Ole Brun Madsen Professor Department of Control...

Documents

Transcript of © Ole Brun MadsenVANS1 VALUE Added Services Ole Brun Madsen Professor Department of Control...