Download ISDN

VALUE Added Services
Integrated Services Digital Network, ISDN & SS7
Voice over IP, VoIP
VAS, VAN, VANS, EDI, EC, EFT
Ole Brun Madsen
Professor
Department of Control Engineering
Aalborg University
© Ole Brun Madsen
VANS
1
ISDN
Integrated Services Digital Network
Ole Brun Madsen
Professor
Department of Control Engineering
Aalborg University
© Ole Brun Madsen
VANS
2
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.
© Ole Brun Madsen
VANS
3
ISDN Reference points
CP
CO
R
S
TA
© Ole Brun Madsen
T
U
NT2
NT1
NT2
NT1
NT2
NT1
VANS
Access
Network
ISDN
Switch
4
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.
© Ole Brun Madsen
VANS
5
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)
© Ole Brun Madsen
VANS
6
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, calltermination, 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)
© Ole Brun Madsen
VANS
7
ISDN Services
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.
© Ole Brun Madsen
VANS
8
ISDN Bearer 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.
© Ole Brun Madsen
VANS
9
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
© Ole Brun Madsen
VANS
10
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.
© Ole Brun Madsen
VANS
11
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.
© Ole Brun Madsen
VANS
12
ISDN Supplementary Services (continued)
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-topoint configuration.
© Ole Brun Madsen
VANS
13
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.
© Ole Brun Madsen
VANS
14
ISDN Supplementary Services (continued)
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.
© Ole Brun Madsen
VANS
15
ISDN Supplementary Services (continued)
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.
© Ole Brun Madsen
VANS
16
ISDN/SS7
Common Channel Signalling System No. 7
SS7
Ole Brun Madsen
Professor
Department of Control Engineering
Aalborg University
© Ole Brun Madsen
VANS
17
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 setup, routing and control.
© Ole Brun Madsen
VANS
18
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)
© Ole Brun Madsen
VANS
19
SS7
Signalling Links
SS7 messages are exchanged between network elements over 64 kbps bidirectional 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)
© Ole Brun Madsen
VANS
20
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.
© Ole Brun Madsen
VANS
21
SS7 Signalling Points
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.
© Ole Brun Madsen
VANS
22
The SS7 protocol stack
IN
HLR
VLR
EIR
AUC
OSI-level
OMAP
Application
ASE
INAP
MAP
Presentation
ISUP
TUP
DUP
TCAP
Session
SSCP
Transport
Network
MTP Level 3
Link
MTP Level 2
Physical
MTP Level 1
© Ole Brun Madsen
VANS
23
The Message Transfer Part (MTP)
OMAP
ISUP
TUP
ASE
INAP
MAP
TCAP
DUP
SSCP
The Message Transfer Part (MTP) is
equivalent to the OSI Layer 1-3
MTP Level 3
MTP Level 2
MTP Level 1
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.
© Ole Brun Madsen
VANS
24
ISUP, TUP
OMAP
DUP
TUP
ASE
INAP
MAP
TCAP
ISUP
SSCP
MTP Level 3
MTP Level 2
MTP Level 1
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
© Ole Brun Madsen
VANS
25
DUP
OMAP
DUP
TUP
ASE
INAP
MAP
TCAP
ISUP
SSCP
MTP Level 3
MTP Level 2
MTP Level 1
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.
© Ole Brun Madsen
VANS
26
SCCP
OMAP
DUP
TUP
ASE
INAP
MAP
TCAP
ISUP
SSCP
MTP Level 3
MTP Level 2
MTP Level 1
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.
© Ole Brun Madsen
VANS
27
Transaction Capabilities Applications Part (TCAP)
OMAP
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.
DUP
TUP
ASE
INAP
MAP
TCAP
ISUP
SSCP
MTP Level 3
MTP Level 2
MTP Level 1
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.
© Ole Brun Madsen
VANS
28
Mobile Application Part (MAP)
IN
The Mobile Application Part
(MAP) handles messages sent
between mobile switches and
databases to support user authentication, equipment identification,
and roaming are carried by TCAP.
OMAP
ISUP
TUP
ASE
DUP
INAP
HLR
VLR
EIR
AUC
MAP
TCAP
SSCP
MTP Level 3
MTP Level 2
MTP Level 1
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.
© Ole Brun Madsen
VANS
29
INAP
IN
OMAP
ISUP
TUP
ASE
DUP
INAP
HLR
VLR
EIR
AUC
MAP
TCAP
SSCP
MTP Level 3
MTP Level 2
MTP Level 1
The Intelligent Network Application Part (INAP) is the application protocol
for IN services.
© Ole Brun Madsen
VANS
30
VoIP
Voice over IP
Ole Brun Madsen
Professor
Department of Control Engineering
Aalborg University
© Ole Brun Madsen
VANS
31
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.
© Ole Brun Madsen
VANS
32
The IP-Telephony Switch
PSTN
© Ole Brun Madsen
IP-Telephony
Switch
IP-Telephony
Switch
IP-Gate keeper
IP-Gate keeper
Telephony
Gateway
Internet
VANS
Telephony
Gateway
PSTN
33
Voice over Internet Protocol (VoIP)
H.323
H.323
Internet
© Ole Brun Madsen
Internet
IP-Telephony
Switch
IP-Telephony
Switch
PSTN
PSTN
VANS
34
Voice over Internet Protocol (VoIP)
H.323
H.323
Internet
© Ole Brun Madsen
Internet
IP-Telephony
Switch
IP-Telephony
Switch
PSTN
PSTN
VANS
35
Voice over Internet Protocol (VoIP)
H.323
H.323
Internet
© Ole Brun Madsen
Internet
IP-Telephony
Switch
IP-Telephony
Switch
PSTN
PSTN
VANS
36
Voice over Internet Protocol (VoIP)
H.323
H.323
Internet
© Ole Brun Madsen
Internet
IP-Telephony
Switch
IP-Telephony
Switch
PSTN
PSTN
VANS
37
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 cooperation with relevant groupings in ITU-T and IETF is essential.
© Ole Brun Madsen
VANS
38
The TIPHON project, ETSI work on Voice over IP
“Black Box”: E.164 / IP Resolution
123456789012 - 172.27.0.1
…
...
1)
dial: +999123456789012
2)
3)
Gateway
Home Gatekeeper
IP-addr: 172.27.0.1
4)
Gatekeeper
phone
switch
IP-terminal:
phone-#:+999-123456789012
IP-address: 172.27.4.134
Router
Phone Network
© Ole Brun Madsen
IP-network
VANS
39
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.)
© Ole Brun Madsen
VANS
40
ITU Series H: Audiovisual and multimedia systems
Systems and terminal equipment for audiovisual services
H.310 (11/96) Broadband audiovisual communication systems and terminals
H.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
networks
which 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
© Ole Brun Madsen
VANS
41
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 BISDN, 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.
© Ole Brun Madsen
VANS
42
VoIP
PSTN
switch
IN
IP DAS
IP RAS
IP Tlf
IP-IN
Transport Network
Access Network
ISDN 30B+D
IP
Router
ATM
Switch
SDH
DXC
© Ole Brun Madsen
VANS
43
Value Added Services
VAS, VAN, VANS, EDI, EC, EFT
Ole Brun Madsen
Professor
Department of Control Engineering
Aalborg University
© Ole Brun Madsen
VANS
44
VAN, VANS
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)
© Ole Brun Madsen
VANS
45
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 management
Access management
Status monitoring,
Broadcast
Accounting
etc.
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 etc
Technical support in EDI, EC and EFT applications.
© Ole Brun Madsen
VANS
46
Electronic Data Interchange (EDI)
EDI
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.
© Ole Brun Madsen
VANS
47
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).
© Ole Brun Madsen
VANS
48
EDI, EFT
VAN
In a typical EDI scenario,
suppliers and retailers
exchange purchase orders and
invoices electronically from
computer to computer through
a VANS provider.
EDI/EFT
EDI/EFT
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.
© Ole Brun Madsen
VANS
49