思科认证5A.pptVIP

Chapter 5:Provision Hardware and Media for the LAN Objectives Upon completion of this chapter, you will be able to: Recognize scalability constraints and issues for standard LAN technologies Recommend Cisco products and LAN technologies that will meet the customer’s requirements for performance, capacity, and scalability in small- to medium-sized networks Identify how to revise a high-level network topology drawing to include hardware and media Evolution of Layer 2 and Layer 3 Services Layer 2 (data link layer) operates within a specific LAN or WAN segment LANs are being revolutionized by use of switching at Layer 2 Layer 3 (network layer) operates between and across segments Includes IP, IPX, and Apple DDP Implemented with routing to interconnect switched workgroups and provide security, QoS options, and traffic management Evolution of Layer 2 and Layer 3 Services (cont.) Networking functions are being integrated into common platforms Reduces the number of networking devices to be purchased, installed, supported, and serviced Problems Solved with Internetworking Media problems Caused by too many devices Solved by dividing networks into separate segments using switches Protocol problems Caused by protocols that do not scale well Solved by dividing networks into segments using routers Need to transport large payloads Need to offer voice and video Solved by using high-bandwidth technologies Switching versus Routing in Network Design The decision to use switching or routing depends on the problem: When to Use Switching Use switches in network designs to provide: High bandwidth in growing networks Low cost per port to increase bandwidth to support applications Easy configuration and administration Minimizes collisions When to Use Routing Use routers in network design to: Segment the network into individual broadcast domains Supply intelligent packet forwarding Support redundant network paths Provide security, policy, and network management Offer manageability, co