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Introduction to WAN Technologies

الكلية كلية تكنولوجيا المعلومات     القسم قسم شبكات المعلومات     المرحلة 4
أستاذ المادة وسام سمير عبد علي بهيه       12/10/2012 10:56:18
Introduction to WAN Technologies

This chapter introduces the various protocols and technologies used in wide- area network (WAN)
environments. Topics summarized here include point-to-point links, circuit switching, packet
switching, virtual circuits, dialup services, and WAN devices.

What is a WAN?

A WAN is a data communications network that covers a relatively broad geographic area and often
uses transmission facilities provided by common carriers, such as telephone companies. WAN
technologies function at the lower three layers of the OSI reference model: the physical layer, the
data link layer, and the network layer.

Point-to-Point Links

A point-to-point link provides a single, preestablished WAN communications path from the
customer premises through a carrier network, such as a telephone company, to a remote network.

Circuit Switching

Circuit switching is a WAN switching method in which a dedicated physical circuit is established,
maintained, and terminated through a carrier network for each communication session.

Packet Switching

Packet switching is aWAN switchingmethod in which network devices share a single point-to-point
link to transport packets from a source to a destination across a carrier network.

WAN Virtual Circuits

A virtual circuit is a logical circuit created to ensure reliable communication between two network
devices.

WAN Dialup Services

Dialup services offer cost-effective methods for connectivity across WANs. Two popular dialup
implementations are dial-on-demand routing (DDR) and dial backup.



WAN Devices

WAN Switch.
Access Server.
Modem.
CSU/DSU
ISDN Terminal Adapter

More in the PDF file.

المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .