basic wan technology

8/12/2019 Basic WAN Technology

1/27

Basic WAN Technology

Priya G


2/27

WAN (Wide Area Network)

A Wide Area Network(WAN) is a computer

network covering multiple distance areas,

which may spread across the entire world.

WANs often connect multiple smaller

networks, such as local area networks (LANs)

or metro area networks (MANs).


3/27

WAN Terms

Customer Premise EquipmentThese

Equipments should be managed by

customer.


4/27

WAN terms continued

A CSU/DSU(Channel Service Unit/Data Service Unit) is

a digital-interface device used to connect a DTE, such

as a router, to a digital circuit, such as a T1 line.

The CSU/DSU implements twodifferent functions.

The Channel Service Unit (CSU)

receives and transmits signals from

and to the WAN line and provides a

barrier for electrical interference from

either side of the unit.

CSU provides echo signal from

telephone company for testing

purposes.

The DSU manages timing errors and

signal regeneration


5/27

WAN terms continued Fig: Outdoor Demarcation Point

Demarcationrefers to the point of lastresponsibility for the service provider.

The modern demarcation point is

the network interface device (NID).

A two-port or four-port patch-panel

will be used as a physical Demarc.

Fig: Indoor Demarcation Point


6/27

WAN Terms continued

The Smart Jack physically terminates the T1 line. If there is a connectivity

issue, the provider will perform a ping test to thesmart jack.

If communication to the smart jack is successful, the provider will assume

the issue resides on the customersside of responsibility.

The smart jack is often locked in a glass enclosure, and labeled with the

T1scircuit number.

In telephony, the local loop (also referred to as a subscriber line) is the

physical link or circuit that connects from the demarcation point of

the customer premises to the edge of the common

carrier or telecommunications service provider's network.


7/27

WAN connection types

Point-to-Point Technologies

Circuit Switched Technologies

Packet Switched Technologies


8/27

Leased Line Technology

Point-to-Point connection between two computers or Local

Area Networks (LANs).

Advantage:

Most Secure

Guaranteed bandwidth

Disadvantage:

Expensive

Eg: PPP, HDLC


9/27

Circuit-Switched Technology

A connection between 2 stations is a dedicated path made of

one or more links.

Three phases:

Setup phase Data Transfer phase

Teardown phase


10/27

Circuit Switching


11/27

Advantages:

less expensive

DrawbackLack of efficiency in using resources

Eg: ISDN, Dial-up


12/27

Packet-Switched Technology

Devices transport packets via a shared single point-to-point or

point-to-multipoint link across a carrier internetwork. Before

information can be exchanged between two end points, they

first establish a Virtual Circuit.

Advantage:

Better EfficiencyDisadvantage:

delay

shared media across link

Eg: X.25, Frame-relay, ATM,


13/27

Packet Switching


14/27

WAN Link Options


15/27


16/27

Analog Dialup


17/27

ISDN


18/27

ISDN

Router with

standard serial

interface,

connected to a

terminal adapter

Router with native

ISDN BRI U or S/Tinterface or PRI


19/27

Leased Line

Leased lines are not only used to provide direct point-to-point connections between Enterprise LANS, they can

also be used to connect individual branches to a packet

switched network.


20/27

WAN with X.25

X.25 provides a low bit rate,shared-variable capacity that may

either be switched or permanent


21/27

Frame Relay

Most Frame Relay connections are based on PVCs rather thanSVCs.

It implements no error or flow control. This leads to reducedlatency.

Frame Relay provides permanent shared medium bandwidth

connectivity that carries both voice and data traffic.


22/27

ATM

Asynchronous Transfer Mode (ATM) is a technologycapable of transferring voice, video, and data throughprivate and public networks.

It is built on a cell based architecture rather than on aframe-based architecture.


23/27

DSL

DSL uses existing twisted-pair telephone lines to

transport high-bandwidth data DSL service is considered broadband, as it uses

multiple frequencies within the same physicalmedium to transmit data


24/27

ADSL Technology

Splitter

The local loop connects the splitter to the DSLAM

DSLAM connected to ISP using ATM technology

Voice and data use separate frequency ranges (voice

0-4Khz, data 20Khx 1Mhz)


25/27

Cable Modem

Enhanced Cable Modems enable two-way.

High speed data transmissions using the same

coaxial lines that transmit cable television.


26/27

Cable Data Network Architecture


27/27

Modern WAN

basic wan technology

Documents