The Wild Area Network technologies


In the world popular word is WAN (Wild Area Network) and as well the world's most popular WAN is the Internet. This may spread across the entire world. Most of the users using internet in the modern world. The reason is most of information's can get from the internet. I am writing a project about WAN Technologies. My main Aims and Objectives are Investigation on different types of WAN Technologies, Analyzing them in term of Costs, Reliability, Performance, Capability, Coverage and Proposal of good design of WAN network based on evidence obtained during the term of research. I try to explain to every reader easy to understand my topic step by step. Because of the reason some projects not clearly explain to readers or users. If it not clearly, readers can not get any information's from the project. That is not useful. In my project I used to some pictures, Bullets point system and break down some of the section step by step for understand all readers.

Introduction to Wide Area Network

A Wide Area Network (WAN) is a computer network and data communications network covering multiple distance areas and that often uses transmission facilities provided by common carriers, such as telephone companies. This may spread across the entire world. WANs connecting multiple smaller networks, such as Local Area Networks (LANs) and Metro Area Networks (MANs). The world's most popular WAN is the Internet. The key difference between WAN and LAN technologies are scalability WAN must be able to grow as needed to cover multiple cities and countries. A number of switches and routers are interconnected to form a Wide Area Network. The set of switches can be connected in different topologies. That means full mesh and half mesh. WAN technologies generally function at the lower three layers of the OSI reference model ...

  • physical layer
  • data link layer
  • Network layer

Both packages that turn and circulation control technologies are used in the WAN. Package control permits consumers to divide public carrier resources so that the messenger can make use of more effective its infrastructure. In a package control assembly, networks connections have into the network of the messenger, and many customers divide the network of the messenger.

The messenger network can create then actual circulation between the places of customers, through which packages of data are delivered of one to the other by the network.

Aims and Objectives


  • To Investigation on different types of WAN Technologies and analyzing them in term of Costs, Reliability, Performance, Capability and Coverage.
  • To Proposal of good design of WAN network based on evidence obtained during the term of research.


  • To learn different types of WAN Technologies and familiar with them.
  • To analyzing and compare WAN Technologies behaviors for the term of Costs, Reliability, Performance, Capability and Coverage.
  • To choosing best WAN connection with in this term and conditions.
  • To design good WAN network based on evidence and information's obtained during the research.
  • To using and learn WAN devices such as Router and Switches. Because of the reason I have to do the proposal WAN designing.

Approach and Methodology

What you are planning to do?

Initially I am planning to learn WAN, types of WAN, WAN technologies and WAN devices as well. Then describe or explain WAN, types of WAN, WAN technologies and compare them evidence from my researching result. Just learn WAN devices and why these important in WAN. How they are participate in WAN networks. Simply plan to design WAN network. Then Design of a Good WAN network on proof during the research.

Why you have chosen to do it?

Already I have little bit knowledge about WAN technology. But I am familiar with networking field. This is very important chapter in the feature. Because of the reason internet is most popular in the world. If I did best, I can easy to get job in my field.

Literature Review

WAN Protocols

A Virtual Private Network (VPN) taking on the Switched Data Network (PSDN) often is used by the organizations for their private and obtained communications. The Virtual Private Network uses encrypting and the technical others to do it appears that the organization has a devoted network while to use divided infrastructure of the Wide area Network. WANs generally utilize different networking technologies and equipment than do LANs. Key technologies often found in WANs include SONET, Frame Relay, X.25, ATM, and PPP.

The wide Area Network technologies and the protocols are mostly data link layer (the layer - 2) the protocols that are defined from a lot of organizations above the time. The main organizations in this space I am IETF for PPP, ITU-T for ATM, Frame Relay, and ISO for X. 25 and SONET etc. [2]

WAN protocols are listed as follows:

  1. Asynchronous Transfer Mode - ATM
    • Multi Protocol over ATM - MPOA
    • Private Network to Network Interface - PNNI
    • User Network Interface - UNI
  2. Synchronous Optical Networks - SONET
    • Ethernet over SONET/SDH
  3. Frame Relay
    • Link Access Procedure/Protocol - LAPF
  4. Point to Point - PPP
    • PPP Bandwidth Allocation Protocol
    • PPP Bandwidth Allocation Control Protocol
    • PPP Bridging Control Protocol
    • Challenge Handshake Authentication Protocol
    • PPP Link Control Protocol
    • Multilink PPP
    • Packet over SONET/SDH
    • PPP over Ethernet
  5. X.25
    • High Level Data Link Control Protocol
    • Link Access Procedure Balanced for X.25
    • ITU -T WAN communication Protocol
    • Signaling System used to connect packet switched networks
  6. Broadband Access
    • Data over Cable Service Interface Specification - DOCSIS
    • Integrated Services Digital Network - ISDN
    • ISDN network layer interface protocol
    • ISDN Link Access Protocol Channel D - LAPD
    • Digital Subscriber Line Technologies - DSL, ISDL, ADSL, HDSL, SDSL, VSDL

WAN including

Wide Area Network including types of WAN, types of WAN technologies and types of WAN devices also. If any one imagines about Wide area network should consider each of them. If select one of the types WANS, that WAN including at least one of the WAN technology and as well some of the important WAN devices such as WAN switches, Routers, etc.

Types of WAN

  • Leased Line
  • Circuit Switching
  • Packet Switching
  • Virtual Circuits
  • Dial-Up Services
  • Cell Relay

Types of WAN Technologies

  • Frame relay
  • X.25
  • ATM
  • PPP

WAN Devices

  • WAN switches
  • ATM switches
  • Routers
  • Access server
  • Modem
  • ISDN terminal adepter
  • Multiplexers


Asynchronous Transfer Mode (ATM) is an electronic digital data transmission technology. ATM is implemented as a network protocol and was first developed in the 1980 series. The goal was to design a single networking strategy that could transport real time video and audio conference as well as image files, text and mails. Two groups the International telecommunication union and the ATM both firm were involved in the creation of the standards.

ATM is a Packets oriented transfer method that uses asynchronous time over multiplex technique. It encodes data into small fixed sized cells and provides data link layer services that run over OSI Layer 1 physical links. This differs from other technologies based on packet switched networks, in which variable sized packets are used. ATM exposes properties from both circuit switched and small packet switched networking, making it suitable for wide area data networking as well as real time media transport (video, audio and images). ATM uses a connection orientated model and establishes a virtual circuit between two end points before the actual data exchange begins. ATM is a core protocol used in the SONET / SDH backbone of the public telephone networks. [4]


ATM is based Integrated on the efforts of the ITU-T Broadband Services Digital Network (B-ISDN) standard. It became originally as a fast transfer technology for voice, video and data over public networks considered. The ATM Forum extended the vision of ATM of the ITU-T for use over public and private networks.

The ATM Forum released work on the following specifications

  • User-to-Network Interface (UNI) 2.0
  • UNI 3.0
  • UNI 3.1
  • UNI 4.0
  • Public-Network Node Interface (P-NNI)
  • LAN Emulation (LANE)
  • Multiprotocol over ATM

ATM Devices and the Network Environment

ATM is a cell switching and technology of multiplexing that combines the advantages of circuit switching (guaranteed the capacity and the delay of constant transmission) with those of commutation of package (flexibility and the effectiveness for the intermittent circulation). It furnishes the width of band of scalable of some millions of bits by the second (Mbps) to a lot of gigabits by the second (Gbps). Because of his asynchronous nature, ATM is the than synchronous more effective technologies, as multiplexing of time division (TDM).

With TDM, every user is assigned to a time slash, and no other station can send this time slot. If a station has of a lot of data to send, it can send only when his slot of time climbs, even if all others slot time are empty. Nevertheless, if a station has nothing to transmit when his slot of time climbs, the time slot is sent empties and is wasted. Because the ATM is asynchronous, the time slashes are available on asks with the news identifying the source of the contained transmission in the heading of every cell of ATM.

ATM Devices

A network of ATM is composed from a switch of ATM and those final points of ATM. A switch of ATM is responsible of the crossing of cell by a network of ATM. The work of a switch of ATM is well defined: It accepts the cell received of a final point of ATM or another switch of ATM. It reads then and updates the news heading of cell and changes quickly the cell to a production interface towards his destination. A final point of ATM (or the end system) contains an adapter of interface of network of ATM. The examples of final points of ATM are locations, the routers, the unities of numerical service (DSUs), the switches of local network, and the video coder-decoders (CODECs). The illustrious figure 27-3 a network of ATM composed from the switches of ATM and those final points of ATM.

ATM Network Interfaces

A network of ATM consists in a series of switches of ATM connected by the links of ATM of race of obstacles in exterior or the interfaces. THE ATM changes the support two primary types of interfaces: UNI and NNI. The UNI one connects the systems of end of ATM (as the hosts and as the routers) to a switch of ATM. The NNI connects two switches of ATM. Depend on if the switch is possessed and is localized to the premises of the customer or publicly is possessed and is worked by the telephone, UNI business and NNI can be more under divided in the public and UNI and private NNIs. An UNI private one connects a final point of ATM and a private ATM changes. His public counterpart connects a final point of ATM or the private switch to a public switch. A private NNI connects two switches of ATM in the same private organization. A public the one connects two switches of ATM in the same public organization. An additional specification, the interface of high-speed intermarried (B-ICI) connects two public switches of the suppliers of different service. The illustrious figure 27-4 the specifications of interface of ATM for the private and public networks.

ATM Services

Three types of services of ATM exist, the permanent true circuits (PVC). Switched true circuits (SVC), and the service of connectionless (that is similar to SMDS). PVC allows direct connectivity between the sites. Of this manner, PVC is similar to a rented line. Among its advantages, PVC guarantees the availability of a connection and does not demand the procedures of organization of call between the switches.

The disabilities of PVCs include static connectivity and the organization manually. Every piece of equipment between the source and the destination must be manually provisioned for the PVC. Of more, no network resiliency is available with PVC. A SVC is created and dynamically is relaxed and remains in uses only provided that the data are transferred. In this direction, the it is similar to a telephone call. The dynamic check of call demands a protocol signalling between the final point of ATM and the ATM switch. The advantages of SVCs include the flexibility of connection and the call organization that automatically can be checked by a device of management of network. Disabilities include the additional time and demanded to establish above the connection.

ATM Switching Operations

The basic operation of a switch of ATM is straightforward. One the cell is received through a link on a VCI known or the value of VPI. The switch looks for the connection value in a table of local translation to determine the harbour going out (or the harbours) connection and the new value of VPI/VCI of the connection on this link. The switch broadcasts then the cell on this link going out with the identifying ones of fitting connection. Because all VCIs and VPIs have the only local meaning through a special link, these values are remapped, as necessary, to every switch.

ATM Addressing

The ITU-T norm is based on the usage of E.164 addresses (similar to telephone numbers) for public ATM (B-ISDN) the networks. The Forum of ATM spread to address ATM to include private networks. It chose the work of subnet or the model of superimposed drawing to address, in which puts to bed it ATM is responsible to do the card of the addresses of layer of network to the addresses of ATM. This model of work of subnet is an alternate one to the addresses of protocol of layer of network of usage (as IP and as IPX) and exist directs protocols (as IGRP and RIP). The Forum of ATM defined an address format base on the structure of the service of network of OSI it no access (NSAP) the addresses.

ATM Connections

The ATM supports two types of connections, Point to Point and Point-to-multipoint. The Point to Point connects two systems of end of ATM and can be one-way (the single way communication) or bidirectional (the two way communication). The point-to-multipoint connects a system of end of single source (known as the basic knot) to the systems of end of multiple destinations (known as the leaves). Such connections are one-way only. The basic knots can transmit to the leaves, but the leaves cannot transmit to the root or to every other on the same connection. The cell replication is done in the ATM by the switches of ATM where the connection splits in two or more of branches.

The it would be desirable in the networks of ATM to have multipoint bidirectional-to-multipoint the connections. Such connections are analogous to the capacities of broadcasting or multicast of local networks of division media, as Ethernet and the Symbolic Ring. A broadcasting capacity is easy to execute in local networks of division media, where all knots on a network segment local single must treat all sharp packages on this segment. Unfortunately, a multipoint-to-multipoint the capacity cannot be executed while using AAL5, which is THE AAL more common to transmit data through a network of ATM. In contrast to AAL3/4, with his Identifying one of Message (MID) the field, AAL5 does not provide way within its cell format to intervals different AAL5 packages on an only connection. This means that all AAL5 sharp packages to a special destination through a special connection must be received in the sequence; otherwise, the destination climbs back up the process will be incapable to rebuild the packages.

This is why AAL5 not at all-to-multipoint the connections can be only one-way. If a leaf knot should transmit an AAL5 package on the connection, for example, it would be received by the basic knot and all other knots of leaf. To these knots, the package sharp by the leaf could be inserted with the packages sharp by the root and the probably other knots of leaf, excluding to climb back up it of any one of the packages inserted.


SONET or synchronous optical network are ANSI standard for the transmission of several types information such as data, voice, and video concerning the optical cables which are widely used by long distance carries. With standard interface devised for communication designed to provide for linking optical networks, SONET by an organization it was formulated as the Exchange Carriers Standards Association (ECSA) and which is later incorporated in ITU recommendation which is confessed as synchronous digital hierarchy, or SDH

Today except comparatively small differences SONET and SDH equivalent. SONET in North America, Japan and SDH in Europe. Together they represent a global standard for digital networks that enable transmission systems around the world, to connect through optical media. [4]

SONET Basics

SONET defines optical signals and one traffic digital same running frame structure for multiplexed. A sentence of standards, that defines the rates and the formats for optical networks, is has it, pacified in ANSI T1.105, ANSI T1.106, and ANSI T1.117. a similar standard, same running digital hierarchy (SDH) become in Europe through the international telecommunication union telecommunication standardization sector uses (ITU-T). SONET equipment is used in general in North America, and SDH equipment is supposed in general everywhere otherwise in the world. Both SONET and SDH is been based on a structure, that has a basic frame format and speed. The framework format used by SONET is the Signal of Synchronous Transportation (STS), with STS-1 as l it equal signal to 51.84 Mbps. A STS-1 framework can be carried an OC-1 signal. The framework format used by SDH is the Unit of Synchronous Transportation (STM), with STM-1 as l it equal signal to 155.52Mbps. A STM-1 framework can be carried an OC-3 signals. SONET and SDH have a hierarchy to signal speeds. The multiple lower those equal signals can be multiplexed to form higher them equal signals. For example, three STS-1 signals can be together multiplexed to form a STS-3 signals, and four STM-1 signals multiplexed together to form a STM-4 signals. SONET and SDH are norms technically of the comparable ones. The term SONET often is used to refer itself to or.

How SONET works

SONET works while dividing a way of transmission of the logical channels called tributaries. A basic unity of the tributary of transmission is STS-1 (the signal of synchronous transportation, level 1) or OC-1 (the carrier view, level 1) the signals. STS describe a transmission signals when they are in an electric state, while OC describes the same circulation after it was transformed in signals views. STS-1 and OC-1 the two works to 51.84 Mbps. (OC- 2 are two times as quickly, OC-3 are three times as quickly, and so on). SONET is based on direct synchronous multiplexing, where to separate signals are directly multiplexed in the quick signals. For example, OC-12 circuits could carry the circulation of four OC-3 links. The rates of line of SONET currently are defined in top to OC-192 (9,953 Gbps), with OC-768 (39.813-Gbps) the capacity foresaw next year. This is strongly quicker than automatic window current rate maximum of 622 Ethernet of Mbps or Gigabit 1 Gbps.


However, the favouring fact directly the card of IP on SONET says that ATM is inefficient because its general expenses are high. The news heading of an ATM of treatment impose a "the cell tax" of almost 60 Mbps on an OC-12 the width of band of the circuit of 622 Mbps. The width of total bandwidth more is reduced further - up to a total of 30 percent - par the network interface had above need to do the card of IP in the frameworks of ATM. An IP-sure - SONET the circuit, on the other hand, uses almost all width of available band. According to Trillium the Numerical Systems, a communications a salesman of software, a test of effectiveness of transmission showed IP directly on SONET attained 95.4 percent of rate of available line but IP on ATM on SONET attained only 79.6 percent. This is illustrated in more of detail in the face on this page. Of more, the supporters say that SONET would be notably useful because most of circulation of IP consists in data that the technology checks notably well, instead of voice or the video. "We think ip-faisant THE CARD OF the load of SONET is the manner more effective of transportation of the data," said Cisco Sharif. The networks using this technology would be thus more profitable, it said, that would help small ISPs and the local telephone carriers do the competition to the big service and the big telecommunications suppliers.

SONET Framing

A standard STS-1 framework is nine rows by 90 8-bit bytes. The first one three 8-bit bytes of every row represents the Section and the Line above. These bits of general expenses understand bits and timekeepers supervision to the different parties of the framework of SONET. There is a column of 8-bit bytes in the load that represents the STS way above. This column "floats" frequently through the framework. His location in the framework is determined by a timekeeper in the Section and the Line above. The combination of the Section and of Line understands above the transportation above, and the remainder is the SPE. For STS-1, a framework of only SONET is transmitted in 125 microseconds, or 8000 frameworks by the second. 8000 fps * 810 B/FRAMEWORKS = 51.84 Mbs, of which loads it is almost 49.5 Mbs, enough to encapsulate 28 DS-1s, a full DS-3, or 21 CEPT-1s. A STS-3 is very similar to STS-3c. The framework is nine rows by 270 8-bit bytes. The first one nine columns to contain the transport the overhead section, and the remainder are SPE. For the two STS-3 and STS-3c, the transportation above (the Line and the Section) is the same. For STS-3 frameworks, the SPE contains three separated loads and three separated ways above fields. In the gasoline, this is the SPE of three separated packed together, the one after the other. In STS-3c, there is only a way an above field for the entire SPE. The SPE for one is a lot of bigger version of an only STS-1 SPE.STM-1 is the SDH (non-d' North America) the equivalent one of a SONET (of North America) STS-3 frameworks (STS-3c to be exact).

For STM-1, an only framework of SDH also is transmitted in 125 microseconds, but the framework is 270 8-bit bytes long by nine wide rows, or 155.52 Mbs, with a nine-byte header of 8-bit byte for every row. The nine-byte header of 8-bit byte contains the more Multiplex and general fresh of Regenerative one. This is almost the same as the Line and to the Section above. Indeed, this is where the norms of SDH and SONET differ.

SDH and SONET are not directly compatible, but only to differ in the 8-bit bytes of some general expenses. This is very not very probable that Cisco never will use an encoder that does not support the two. SONET widely is much deployed in the space of Telco, and frequently is used in a ring configuration. The devices as ADMs itself on the ring and behave as LTE layer devices; these devices remove individual chains and the pass side issue to the layer of PTE. All current cards of line of Cisco and Transports Adapters (the STEP) uses PTE THEM layer devices; these devices finish the meeting of full SONET and L2 encapsulation. They are Package on SONET (POS) the cards that indicate the mass transmission of data on the frameworks of SONET. There are two RFCs that describe the process of POS: RFC 1619, PPP on SONET/SDH, and RFC 1662, and PPP in HDLC-come the Supervision. These products of Cisco cannot sit directly on a ring of SONET or SDH. One of the most hangs of some LTE-l apparels of layer, as ADM. The equipment as a SONET Router Integrated (ISR) has the functional character of PTE and LTE; therefore it can finish and can go through the data.

Configuration Issues

These parameters affect the configuration of devices of SONET

  • Clocking
  • Clock Source Internal
  • Loopback
  • Framing
  • Payload Scrambling
  • S1S0 Flag
  • J0 Flag - 0-255
  • C2 Flag - 0-255
  • Flag
  • Alarm Reporting
  • Pos Report
  • Alarm Thresholds
  • Pos Threshold

Frame Relay

Frame Relay is a networking protocol and a high-performance. It is a telecommunication service designed for cost efficient data transmission for internet traffic between local area networks and between end points in a wide area network. That is work at the bottom two levels of the OSI model layers. Such as physical layer and data link layer. It is an example of packet switching technology, which enables end stations to dynamically share network resources. Frame relay puts data in a variable size unit called a frame and leaves any some need error correction up to the end points, which speeds up full data transmission. Frame relay is often used to connect local area networks with bigger backbones as well as on public wide area networks and also in private network environments with leased lines over T-1 lines.

Frame relay was conceived at first for the usage through the Integrated Services Network (ISDN) the interfaces. Today, it is used on a selection of other interfaces of network also. Framework relay is an example of a technology of changed package. The networks of changed package render capable the end stations dynamically to divide the means of network and the width of available band. To follow it two techniques are used in the technology package changing...

  • Variable-length packets
  • Statistical multiplexing

The packages of variable length are used for the transfers of more effective data and flexible. These packages are changed between the various segments in the network until the destination is reached. The technical statistics of multiplexing check the network access in a network package changed. The advantage of this technique is that it suits more flexibility and the more effective usage of width of band. Most of popular local networks of today, as Ethernet and the Symbolic Ring, are networks packages changed.

Framework relay often is described as a streamlined version of X. 25, offering less than the sturdy capacities, as windowing and as rebroadcast of last data that are offered in X. 25. This is because Frames Relay typically works on the opportunities WAN that offer the services of more reliable connection and a higher degree of reliability than the available opportunities during the last years 70 and the last beginning of the years 80 that used the common platforms for X. 25 WAN. As preceding mentioned, Relay of Framework strictly is a Layer 2 continuations of protocol, while X. 25 furnish services to Puts to bed 3 (the network layer) also. This renders capable Relay of Framework to offer the effectiveness of transmission of superior quality and bigger than X. 25, and mark Frame suitable Relay for the applications LAN current, as the interconnection of local network.

Frame Relay Devices

The attached devices to a WAN of Frame Relay belong to the to follow two general categories...

  • Data terminal equipment (DTE)
  • Data circuit-terminating equipment (DCE)

DTEs are considered to finish generally equipment for a specific network and typically are localized on the premises of a customer. Indeed, they could be possessed by the customer. The examples of devices of DTE are final, the personal computers, the routers, and the bridges. DC is the devices of internetworking carrier possessed. The goal of Equipment of DCE is to furnish measures the time and the commutation services in a network that are the devices that transmit in data fact by the WAN. In most of the cases, these are the package switches.

The connection between a device of DTE and a device of DCE consists in a layer a physical component and a link dispose put to bed the component. The physical component defines the specifications more mechanical, more electric, more functional and of procedure for the connection between the devices. One of the specifications of interface of physical layer the most ordinarily used are recommended it standard (RS)-232 specifications. The component of layer of link defines the protocol that establishes the connection between the device of DTE, as a router, and the device of DCE, as a switch. This chapter examines a protocol ordinarily used specification used in the management of network of WAN the protocol of Relay of Framework.

Frame Relay Error Checking

Frame relay uses a mechanism error verifying common known as the cyclic check of redundancy (CRC). The CRC compares two premeditated values to determine if the errors arrived during the source transmission to the destination. Frame relay reduces the network above while executing to verify error instead of the error correction. Frame relay typically is executed on the media of reliable network; therefore data integrity is not sacrificed because the error correction can have left for the haut-couched protocols running on frame relay.

Frame Relay Network Implementation

An implementation of network of Relay of private Frame town is to equip a T1 more multiplex with Relay of Frame and the interfaces of Relay non-framework. The circulation of Relay of frame out is dispatched the interface of Relay of Frame and on the data forms a network. The circulation non-frame of Relay is dispatched to the application or to the fitting service, as an exchange of private branch (PBX) for the service of the telephones or to an application of video teleconference. A typical network of Relay of Frame consists in a number of DTE devices, as the routers, connected to the remote port on the equipment more multiplex through the services of race of obstacles in traditional exterior as T1, fractionalise T1, or the circuits of 56 Kb.

Frame Relay Frame Formats

To understand a good part of the functional character of Relay of Frame, the is servable to understand the structure of the frame of Relay of Frame. The figure 10-4 comb the basic format of the frame of Relay of Frame, and Figure 10-5 illustrates the version of LMI of the frame of Relay of Frame. The flags indicate the beginning and the frame end. Three primary components form the frame of Relay of Frame. The sector heading and addresses, the portion of given users, and the sequence of check of frame (FCS). The address sector, that is 2 8-bit bytes in the length, is understood of 10 bits representing the true identifying one of circuit and 6 bits of fields linked to the congestion direction. This identifying one ordinarily is referred to as the identifying one of connection of data link (DLCI).

Point to Point - PPP

In networking Point to Point protocol is a data link layer protocol. It's commonly used to establish a direct connection with in a two networking nodes. Point to Point Protocol can provide

  • Connection authentication
  • Transmission encryption privacy
  • Compression

Point to Point Protocol is used over many types of Physical layer networks including

  • Serial cable
  • Phone line
  • Trunk line
  • Cellular telephone
  • Specialized radio links
  • Fiber optic links (SONET)

Most of the internet Service providers (ISP) use Point to Point Protocol for user dial up access to the internet. Point-to-Point Protocol (PPP) originally emerged as an encapsulation protocol for transporting IP traffic over point to point links. Two encapsulation forms of PPP, Point to Point protocol over Ethernet and Point to Point protocol over ATM are used by ISP to connect Digital Subscriber Line (DSL) internet service. Point to Point Protocol also established a standard for the assignment and management of

  • IP addresses
  • Asynchronous (start/stop) and bit oriented synchronous encapsulation
  • Network protocol multiplexing
  • Link configuration
  • Link quality testing
  • Error checking
  • Option negotiation for such capabilities as network layer address negotiation and data compression negotiation.

Point to Point Protocol supports these functions by providing an extensible Link Control Protocol (LCP) and a family of Network Control Protocols to negotiate optional configuration parameters and facilities. PPP was designed to work with numerous network layer protocols, including internet protocols, Novell's internet work packet Exchange such as NBF and Apple talk. [4]

PPP Components

PPP provides a method to transmit datagram on the links of race of obstacles in mass exterior. PPP contains three principal components...

  • A method to encapsulate datagram on the mass links. PPP uses the High Data Link up the Check (HDLC) the protocol as a basis to encapsulate datagram on the links of race of obstacles in exterior. (To see Chapter 16, "the Synchronous Data Link up the Check and the Drifts," for more of information on HDLC).
  • An extensible LCP to establish, configure, and try the connection of link of data.
  • A family of NCPs to establish and configure different form a network the protocols of layer. PPP is conceived to allow the simultaneous usage of protocols of layer of multiple networks.

General Operation

To establish communications on a link of race of obstacles in exterior, the PPP originating sends first the frameworks of LCP to configure and (optionally) tries the data link. After the link was established of the and the optional opportunities were negotiated as necessary by the LCP, the PPP originating sends the frameworks of NCP to choose and configure one or the protocols of layer of more of network. When each of the protocols chooses layer of network were configured, the packages of every protocol of layer of network can be sent the link. The link will remain configured for the communications until LCP or explicit NCP frame near the link, or until some external event arrives (for example, an inactivity minute expires or a user intervenes).

Flag - Single 8-bit byte only that indicates the beginning or the end of a framework. The flag field consists in the binary sequence 01111110.

Address - Single 8-bit byte only that contains the binary sequence 11111111, the address of standard transmission. PPP does not assign the addresses of individual station.

Control - Single 8-bit byte only that contains the binary sequence 00000011 that calls the transmission of data of user in an unsequenced framework. A service of link of similar connectionless thereto of Check of Logical Link (LLC) Types 1 is provided.

Protocol - two 8-bit bytes that identify the encapsulated protocol in the field of information of the framework. The values the more today of the field of protocol are specified in the Assigned Numbers the most recent Request for the Commentaries (RFC).

Data - Zero or more of 8-bit bytes that contains the datagram for the specified protocol in the protocol field. The end of the field of information is found while localizing the sequence of flag of closing and allow 2 8-bit bytes for the field of FCS. The length maximum implicit of the field of information is 1,500 8-bit bytes. By the previous agreement, consenting the implementations of PPP can use other values for the news maxima receive the length.

Frame check sequence (FCS) - normally 16 bits (2 8-bit bytes). By the previous agreement, consenting the implementations of PPP can use one of 32 little (4-byte) FCS for the detection of improved error. The LCP can negotiate modifications to the structure of framework of standard PPP. The modified frameworks always will be nevertheless clearly distinguishable of the standard frameworks.

Physical Layer Requirements

PPP is capable through any operation interface of DTE/DCE. The examples include EIA/TIA-232-C (recently RS-232-C), EIA/TIA-422 (recently RS-422), EIA/TIA-423 (recently RS-423), and Sector of Normalization of Telecommunications of Union of International Telecommunications (ITU-T) (recently CCITT) V. 35. The only absolute condition taxed by PPP is the provision of a circuit duplex, devoted or changed, that can work in an asynchronous or synchronous method not very mass, transparent to the frameworks of layer of link of PPP. PPP does not impose restrictions as for the transmission rate otherwise that these taxed one by the interface of special DTE/DCE in the usage.

PPP Link-Control Protocol

The PPP LCP provides a method of the arranging, shapes, maintenance, and finishing the point-to-point connection. LCP goes through four distinct phases. First connection arrangement and configuration negotiation take place. Before any network datagram (for example, IP) can be exchanged puts in layers, must open LCP first the connection and must negotiate configuration parameter. This phase is completely if configuration recognition frames both, was sent and was received. This is followed of connection quality decision. LCP permits that an optional connection quality decision phase the connection arrangement and the configuration the negotiation phase following. In this phase, the connection is tested to determination whether the connection quality is sufficient, to propose network layer protocols. This phase is optional.

LCP can delay the transmission of information of protocol of layer of network until this phase is complete. To this point, form a network the negotiation of configuration of protocol of layer arrives. After LCP finished the phase of determination of quality of link, form a network the protocols of layer separately can be configured by the fitting NCP and can be brings and brought down at any moment. If LCP closes the link, it informs the protocols of layer of network for that they can take the fitting action. At last, the link conclusion arrives. LCP can finish the link at any moment. This is of ordinary one does to the request of a user but can arrive because of a physical event, as the loss of carrier or the expiration of a minute of unoccupied period. Three classes of frameworks of LCP exist. The frameworks of link establishment are used to establish and configure a link. The frameworks of link conclusion are used to finish a link, and frameworks of link discussion are used to manage and debug a link. These frameworks are used to accomplish the work of each of the phases of LCP.


X.25 is an International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) protocol. This is standard for the WAN communications that explains how WAN connections between the devices of customer and the network devices are established and are maintained that the connection. X. 25 are conceived to work efficiently without taking account of the system type connected to the network. X. 25 devices include DTEs, DC, and PSNs. It typically is used in the networks packages changed (PSNs) of businesses of public transportation, as the telephone businesses. The subscribers are loaded based on their network usage.

The development of the X. 25 norms was inaugurated by the businesses of public transportation. It was a need for WAN protocols capable of providing connectivity through the networks of public data (PDNs). X.25 is now administered as an international standard by the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T). X.25 connections contain both SVCs and PVCs within the physical circuit. X.25 uses the following three protocols, which map to the bottom three layers of the OSI reference model...

  • PLP - which maps to the network layer
  • LAPB - which maps to the data link layer
  • X.21bis, EIA/TIA-232, EIA/TIA-449, EIA-530, and G.703, which map to the physical layer.

X.25 Devices and Protocol Operation

X. 25 devices of network belong to three general categories, data terminal equipment (DTE), data circuit-terminating equipment (DCE), and packet-switching exchange (PSE). The devices of final equipment of data are the end systems that communicate through the X. 25 networks. They are of ordinary one of the final, the personal computers, or the network hosts, and are localized on the premises of individual subscribers. The devices of DCE are devices of communications, as the switches of modems and package that furnish the interface between the devices of DTE and a PSE, and generally are localized in the carrier opportunities. PSE is switches that compose the mass of the network of the carrier. They transfer data of a device of DTE to another by the X. 25 PSN. The illustrious figure 17-1 the relations among the three types of X. 25 devices of network.

Determining the WAN Types to Use

When designing or planning a wide area network (WAN), one of the most challenging issues is choosing the correct WAN connection type. You need to consider several factors before implementation can begin and a solid understanding about all of the connection types is critical to making the right choice. Most carriers offer three connection types.

  1. Leased Line
  2. Circuit switched connections
  3. Packet switched or cell switched connections
  4. Dedicated connections
  5. Broadband Access

Every type of connection has its advantages and its disadvantages. That it has to every type of connection of to offer with the given consideration to...

  • Bandwidth
  • Availability
  • Cost
  • Ease of management
  • Application Traffic
  • Access Control

Leased lines

Leased lines, as the name suggests, are lines of telephone communications that you rent for your private usage. The Leased lines provide constant (as opposed to dial-up) the numerical connections between two sites on the copper wire. You can leased lines to a lot of different speeds of 56 Kbps to 274 Mbps with the connections the more towns to be T1 (1,544 Mbps) and fractional T1 (the various speeds that are all the multiples of 64 Kbps). Recently, the telecommunications suppliers Began offering burs table T1 (the speeds that change according to the ask momentary of your network, until 1.544 Mbps). For the rates of 128 Kbps and above, you can update your service comparatively easily. To increase your transmission rate you simply new provisions services of the supplier of telecommunications, and you must not change your equipment of connection network. T1 services furnish the very good rates of response for the hundreds of simultaneous users. Of all the technologies of local network in this chapter, T1 lines constitute the most common technology for connecting branches to the Internet.

Leased line communications are defined by a series of standards. Common standards include, Standard Transmission rate

DS-0 (digital signal level 0) 64 Kbps
DS-1 (digital signal level 1) 1.544 Mbps
DS-3 (digital signal level 3) 44.736 Mbps

The telephone circuits execute these standards. For example, the telephone lines called T1 lines are in accordance with DS-1 norms, while T3 lines are in accordance with DS-3 norms. You can use these circuits of carrier of T to transmit/receives data, voice, and the video simultaneously (the signals Are Combined, or multiplexed, on the line).

Implementing leased lines

The leased line consists in of ordinary two twisted pairs of drivers of copper. These sons finish at your site in a taken one. The taken is connected, in the bend, to a unity of service of chain / them given maintain unity (union of officials / DSU) that furnishes the numerical services of similar connection to these furnished one by a modem for the analog connections. Generally, the union of officials / DSU receives signals entering office of the telephone central business through the one- or the two pairs of son treats the signals and the pass on a router on your network of local sector. For the signals going out, the union of officials / DSU receives the news of the router, the code for the trip on the line of telephone business, and the envoy on his destination.

To the provision a leased line, you must call your business or your telecommunications your local telephone carriers. For every pair of buildings that you wish to connect, you must install a rented line and a union of officials / DSU to every location. The union of officials / DSUs must be compatible itself, and with the equipment to the business the telephone central office (for example, they must use the same arrangements encoding when the news of envoy / reception). There is not restriction on the distance between the two points connected by a rented line. However, the leased line charges vary directly with the distance between the connected points just like with the speed of the line.

DSL, the modem cable, and the waves radio is the technologies of competitor to the rented lines. They can carry data, the video, and the news of voice on the long distances to the reasonable rates. Frame the relay services are so competing to T1 rented lines in the matter of the data, but the framework relay cannot carry the video with equivalent reliability. The other technologies of competitor include the method of asynchronous transfer (ATM) and the technologies by low satellites.

Circuit switched connections

Circuit switched connections are currently the most popular type of Wide Area Network connection. Circuit switching transmits data streams and datagram's across dedicated physical circuits. To provide asynchronous dial - in and ISDN services, most of the telephone companies use circuit switching.

Packet-switched or cell-switched connections

Packet-switched and cell-switched networks are point-to-point - PPP connections that travel across a public carrier's network. While these types of connections are more expensive than asynchronous dial-in and ISDN connections, packet-switched and cell-switched services can provide very high bandwidth solutions at a lower cost than dedicated connections.

Examples of packet-switched and cell-switched networks

  • Frame Relay (packet-switched)
  • X.25 (packet-switched)
  • Asynchronous Transfer Mode or ATM (cell-switched).

As a general rule, packet-switched connections are most cost-effective in the following


  1. Long connect times
  2. Large geographic distances
  3. High link utilization
  4. High peaks of critical traffic

Dedicated connections

Dedicated connections are point-to-point - PPP serial connections that offer fixed, permanent connections to remote networks. Dedicated links can provide up to 44.736 Mbps speeds over a public carrier's network. Since dedicated connections are fixed, permanent connections there are less overhead required to establish communication between two sites. And because dedicated connections offer low overhead and high-speed transmissions, they're excellent solutions for companies requiring high-bandwidth, 24/7 WAN connections. However, the carrier fees and support costs for dedicated connections are on the high side.

Broadband Access

The access to Internet moves itself dial-up modems and slows down connections to the high-speed access that uses a technology selection that take advantage of current telephone and the infrastructures of distribution of cabled television to furnish the high-speed access to the Internet, according to the Figure 6. The examples of this include DSL and the cable of quick speed high-speed technologies. The high-speed one generally is defined as the data rate supported above 128 kbps. The high-speed one can allow the personnel of removed office and the small office / the offices to residence (SOHOs) to connect to the central site to the highest rates of data than the technologies on traditional request.

The high-speed access of quick speed to the Internet by a high-speed point of presence (POP) and then to the business networks that use private potential assured networks (VPN) is a reality for a lot of users in the today world-wide one in network. This high-speed access has the potential one directly to improve the productivity of employee and to provide a foundation for the new voice and the services to the video businesses on the Internet.

A lot of commercial corporations and the educational institutions executed solutions of high-speed access for the access by the suppliers, the customers, and the personnel. The usage of the Internet for the Site-to-site connectivity using VPNs is increasing, especially for these types of connections and of subsequent circulation. The technology options, of access and high-speed include modems cables and the various forms of technology of DLS including Asymmetrical DSL (ADSL), ISDN DSL (IDSL), Symmetrical DSL (SDSL), and DSL of Data of High Rate (HDSL). The problem more common in to offer these services of high-speed one to the removed users are the lack of availability of the modem cable and/or the services of DSL in the sector of the local user because of the infrastructure lacks.

Project Plan

Work Breakdown Structure


I am going to study about the investigating and designing WAN technologies terms of their functionality and limitations. This will provide me a very good idea and knowledge of their characteristics and how each of them is applicable to a WAN network in terms of their performance and reliability. I am planning to setup a network which basically will consist of access points, routers and WAN some other WAN devices. The WAN network will be consistently monitored. I am doing in the questions about my goal for easy to approach it or easy to get it. If I find out that answers for the questions that goal should done. Because of all the questions make it step by step and as well break down part by part. The reason is easy to get information's from source such as Internet, Books, Magazines and some academic papers.

  • Understand different types of WAN technologies
  • How are them working?
  • What are the basic equipments needs to operate or configure?
  • Who is control WAN? Or who Administrator to WAN?
  • How is control WAN?
  • Who are the users WAN?
  • What type of users using WAN?
  • Analyzing type of WAN technologies
  • Get result to analyzing
  • Select best WAN technology during my research periapt
  • Give the reason for it. (Why chosen that type of WAN?)
  • How to plan to design WAN?
  • What is the main think to design WAN?


1. This is main scoping area to WAN technologies. I have to explain about different type of WAN technologies and as well understand about them. Each technology has different types of behavior and compares them behaviors to each other WAN technology types. These are some important WAN technologies...

  • ATM
  • Frame Relay
  • Point to Point - PPP
  • X.25

2. This is a second scoping area for this project. This provides Proposal of good design of WAN network. Based on evidence and as well information's for the design WAN network obtained during the term of project scheduling time and research.

Practical / Simulation

Planning the network

To begin the planning process, you should draw a sketch of the buildings you wish to connect. For each building, draw a line to all the other buildings with which it must share information, and label each line with the following information,

  • The distance between buildings
  • The kinds of information that will be exchanged. For example, if School Building A must exchange email with School Building B, then draw a line between these two buildings and label the line email. If School Building a must also receive cable TV transmissions, draw a line labeled TV to the cable provider. Be sure to plan for kinds of information you'll use in the future as well as the kinds you exchange today.
  • The number of computers in each building
  • The number of people who will use those computers at various times of day
  • The tasks that will engage these people at various times of day.

For example, will your staff and students primarily use electronic mail? Will they use the World Wide Web and do so more at some times of day than others? Do you have a student learning system in one building which must accommodate 30 simultaneous logins at the beginning of class periods during the day? Will your classrooms collaborate on building Web pages, including large graphics? Do you need to share video or voice transmissions? There are many such questions, and it is critically important that you think carefully through them. You should describe every action that will take place, including its duration and number of participants.

Once you've developed your drawing, you should work with a wide area network integrator to convert this functional description into a technical specification. Remember that your integrator's network plan is only as good as your description. If you omit services or misjudge its usage, then your network may not deliver reliable or sufficient services.

The final network map created by your integrator may not look exactly like the map you drew. For example, imagine a wide area network that includes four school buildings. You may have connected each building with all others. However, your network integrator may link each of these buildings to a central one (instead of each to the other). In many ways, the physical shape of the network is less important than its performance. Your job as technology leader requires not so much that you understand the physical design of your WAN as that you verify its capabilities. You should discuss with your integrator the details of each service as well as the performance levels that you expect from the network.

A candidate following a programmed of learning leading to this unit will be able to:

  • Demonstrate understanding of scaling IP addresses
  • Identify the differences between WAN services
  • Demonstrate PPP operation to encapsulate WAN data on routers
  • Demonstrate understanding and knowledge of Integrated Services Digital Network (ISDN) and Dial-on-Demand (DDR)
  • Demonstrate understanding and knowledge of Frame Relay
  • Demonstrate awareness of network management
  • Demonstrate awareness of optical networking
  • NB Before starting this unit please refer to the Vendor website for up-to-date specifications, Examination objectives and availability.

WAN Design Requirements

  • WAN communication is often called a service because the network provider often charges users for the WAN services it provides.
  • All technologies and features used in WANs are developed to meet the following design requirements:
    1. Optimize WAN bandwidth.
    2. Minimize cost.
    3. Maximize the effective service to the end users.
  • Traditional shared-media networks are now being overtaxed because of the following:
    1. Network usage has increased.
    2. Application software evolution is continually more demanding.
    3. Applications increasingly require distinct network qualities of service.
    4. An unprecedented number of connections are being established.
    5. The explosive growth of corporate intranets and extranets has created a greater demand for bandwidth.
    6. The increased use of enterprise servers continues to grow to serve the business needs of organizations
  • New WAN infrastructures must be
    1. More complex.
    2. Based on new technologies.
    3. Able to handle an ever-increasing (and rapidly changing) application mix with required and guaranteed service levels.
  • Within the next five years, there's an expected 300% traffic increase.

Factors Affecting Design

Environmental Variables

Where are all the nodes?

Performance Constraints

What level of reliability? Host / client speeds? Traffic throughput?

Networking variables

What is the topology? What are the traffic's characteristics?

Factors that affect Availability


Response time

Access to Services

WAN Design Models

* Network designs tend to follow one of two general design strategies:

  • Mesh
    • The network topology is flat.
    • All routers perform essentially the same functions, and there is usually no clear definition of where specific functions are performed.
    • Expansion of the network tends to proceed in a haphazard, arbitrary manner.
  • Hierarchical
    • The structure the network is organized in layers, each of which has one or more specific functions.
    • Data traffic flows based on source / destination addressing.

Hierarchical WAN Design Model

* Benefits to using a hierarchical model include the following:

  • Easier to implement.
  • Easier to manage.
  • Easier to troubleshoot.
  • Improved scalability.
  • Predictability.
  • Protocol support.

Three Hierarchical WAN Design Layers

* A hierarchical network design includes the following three layers:

  • The CORE layer:
    • Provides optimal transport between sites.
  • The DISTRIBUTION layer:
    • Provides policy-based connectivity.
  • The ACCESS layer:
    • Provides workgroup and user access to the network.

* Could also be called the 3 levels of a router hierarchy.

WAN Connection Speed Comparison

Figure 1-9 illustrates the WAN speeds for typical technologies. In this example, a network Administrator must select a WAN option, based on the amount of required bandwidth. The speeds, costs, and availability of WANs vary internationally. For example, in North America, high-bandwidth speeds such as T1 are readily available at reasonable prices. Europe offers comparable speeds such as E1, but the prices tend to be higher. Other parts of the world offer limited WAN services with lower bandwidth speeds, typically up to 64kbps, and the costs are higher. Broadband options include DSL and high-speed cable modems. Broadband is generally defined as any sustained speed above 128 kbps, but that might soon be changing. Broadband can allow remote office staff and SOHOs to connect to the central office LAN at high speeds. A cable modem can provide up to 90 times the speed (4 Mbps) of a dialup connection for remote access. DSL is a technology that enables the use of unused bandwidth that already exists on a regular phone line to deliver fast digital data transmission up to 25 times the speed (approximately 1 Mbps) of a dialup connection without affecting the analog telephone service used.

Investigating WAN technologies

Besides discussing your network's functional requirements, you should also raise the following questions with your wide area network integrator.

What technologies are available in your geographic area?

To make wide area connections, you will use the services of local telephone companies and other communications vendors such as MCI, Sprint, or AT&T. Different vendors offer different technologies. When you plan your WAN, you should check with you local telephone company and other communications providers to see what they support.

What are the installation and recurring costs for each technology?

WAN technologies vary in their start up and recurring costs. Starts up costs include installation fees and equipment to be purchased. Recurring costs include service contracts for the equipment and connections as well as communications line charges and per-call connection charges. Some technologies cost more as the distance between connections increases (just as long-distance telephone calls cost more than local calls), while others are distance insensitive. Some technologies cost more as the amount of data you send increases, while others charge a flat rate regardless of the amount of data. You'll need to think carefully about the placement, frequency, and duration of your connections and choose a technology that gives you a good balance of cost and performance.

What kinds of data does each technology carry?

Some technologies are suited best to carrying data like electronic mail and documents you create. More powerful technologies carry both data and video or voice transmissions. You should determine what kinds of data you need to exchange and select an appropriate technology.

How fast is the connection?

WAN technologies vary significantly in their transmission rates. The slowest technologies run at about the same speed as fast modems 56 Kbps and can provide connections for just a few simultaneous users to exchange data (not voice or video). The fastest technologies run many times faster than Ethernet and can service hundreds of simultaneous users exchanging any kind of information. Some WAN technologies carry data at two different transmission rates they send downstream (to the user) faster than they send upstream (from the user). You must make sure that the transmission rates accommodate the kinds of information you wish to share and the number of users you support.

Are there distance limitations for the technology?

Some WAN technologies impose limits on the distances that they can carry data. Make sure that the WAN technology you choose can negotiate the distances between your sites.

Does the technology support dial-up connections or permanent connections?

Permanent connections between sites are preferable to dial-up connections because they are easier to manage and provide more durable service. In addition, dial-up connections may be inadequate for video, voice, and other kinds of data that must travel in continuous streams. However, dial-up connections may be substantially less expensive than permanent connections. You should confer with your wide area network integrator to determine whether the price of permanent connections is worth the benefit they bring for your particular situation.


In my point of view, I hope this project should be using full all computer networking fielders in the world. This is just initializing about of the WAN Technologies and as well this part is only how can I approach my aim and targets. After that I am going to write and explain to deeply about WAN technologies in next semester. It means introduction of WAN, what are the WAN types, what are the WAN technologies and what are the WAN protocols. Because of the reason I explained step by step for the readers. If compare, the readers should know knowledge about WAN, before reading and after reading this project. I hope after reading gets more knowledge.

Source of information's obtained by some other resources, and fully understand me and applied to them easy words in my view for the readers. Those words are not belongs to me. I note it in the reference section where I from get it this notes.

I have to honestly thank full Mrs. Jorce WO and Dr. Nic as well. Because of them guiding and co-operate to me about that project topic start to end. They spent them valuable time for me and my project.


  1. WAN -
  2. Protocols -
  3. McQuerry, Steve (November 19, 2003). 'CCNA Self-Study: Interconnecting Cisco Network Devices (ICND), Second Edition'. Cisco Press. ISBN 1-58705-142-7.
  5. Amos E. Joel, Jr., Asynchronous Transfer Mode (IEEE Press, 1993)
  6. Approach:-

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