PPt_4face_021208.jpg © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Presentation_ID ‹#› Cisco_NewLogo Cisco Chapter 1: Introduction to Switched Networks Routing and Switching Cisco Networking Academy program Routing & Switching Chapter 1: Introduction to Switched Networks Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Chapter 1 §1.0 Introduction §1.1 LAN Design §1.2 Switched Environment §1.3 Summary Chapter 1 Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Chapter 1: Objectives §Upon completion of this chapter, you will be able to: §Describe convergence of data, voice, and video in the context of switched networks. §Describe a switched network in a small-to-medium-sized business. §Explain the process of frame forwarding in a switched network. §Compare a collision domain to a broadcast domain. 1. Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Converged Networks Growing Complexity of Networks §Our digital world is changing. §Information must be accessed from anywhere in the world. §Networks must be secure, reliable, and highly available. § 1.1.1.1 Growing Complexity of Networks Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Converged Networks Elements of a Converged Network §Collaboration is a requirement. §To support collaboration, networks employ converged solutions. §Data services include voice systems, IP phones, voice gateways, video support, and video conferencing. §Call control, voice messaging, mobility, and automated attendant are also common features. 1.1.1.2 Elements Of A Converged Network Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Converged Networks Benefits of a Converged Network §Multiple types of traffic; only one network to manage. §Substantial savings over installation and management of separate voice, video, and data networks. §Integrates IT management. § 1.1.1.2 Elements Of A Converged Network Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Converged Networks Borderless Switched Networks §The Cisco Borderless Network is a network architecture that allows organizations to connect anyone, anywhere, anytime, and on any device securely, reliably, and seamlessly. §Cisco Borderless Network is designed to address IT and business challenges, such as supporting the converged network and changing work patterns. 1.1.1.3 Borderless Switched Networks Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Converged Networks Hierarchy in the Borderless Switched Network §Borderless switched network design guidelines are built upon the following principles: §Hierarchical §Modularity §Resiliency §Flexibility § 1.1.1.4 Hierarchy in the Borderless Switched Network Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Converged Networks Core, Distribution, Access 1.1.1.5 Core, Distribution, Access Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Switched Networks Role of Switched Networks §Switching technologies are crucial to network design. §Switching allow traffic to be sent only where it is needed in most cases, using fast methods. §A switched LAN: §Allows more flexibility §Allows more traffic management §Supports quality of service, additional security, wireless, IP telephony, and mobility services § 1.1.2.1 Role of Switched Networks Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Switched Networks Form Factor §Fixed Platform 1.1.2.2 Form Factor Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Switched Networks Form Factor (cont.) §Modular Platform 1.1.2.2 Form Factor Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Switched Networks Form Factor (cont.) §Stackable Platform 1.1.2.2 Form Factor Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Frame Forwarding Switching as a General Concept §A switch makes a decision based on ingress and a destination port. §A LAN switch keeps a table that it uses to determine how to forward traffic through the switch. §Cisco LAN switches forward Ethernet frames based on the destination MAC address of the frames. § § 1.2.1.1 Switching as a General Concept in Networking and Telecommunications Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Frame Forwarding Dynamically Populating a Switch MAC Address Table §A switch must first learn which devices exist on each port before it can transmit a frame. §It builds a table called a MAC address or content addressable memory (CAM) table. §The mapping device <-> port is stored in the CAM table. §CAM is a special type of memory used in high-speed searching applications. §The information in the MAC address table used to send frames. §When a switch receives an incoming frame with a MAC address that is not found in the CAM table, it floods it to all ports, but the one that received the frame. 1.2.1.2 Dynamically Populating a Switch MAC Address Table Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Frame Forwarding Switch Forwarding Methods Add a header 1.2.1.3 Switch Forwarding Methods Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Frame Forwarding Store-and-Forward Switching §Allows the switch to: §Check for errors (via FCS check) §Perform automatic buffering §Slower forwarding process 1.2.1.4 Store-and-Forward Switching Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Frame Forwarding Store-and-Forward Switching (cont.) 1.2.1.4 Store-and-Forward Switching Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Frame Forwarding Cut-Through Switching §Allows the switch to start forwarding in about 10 microseconds §No FCS check §No automatic buffering 1.2.1.5 Cut-Through Switching Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Frame Forwarding Cut-Through Switching (cont.) 1.2.1.5 Cut-Through Switching Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Switching Domains Collision Domains §A collision domain is the segment where devices must compete to communicate. §All ports of a hub belong to the same collision domain. §Every port of a switch is a collision domain on its own. §A switch break the segment into smaller collision domains, easing device competition. § 1.2.2.1 Collision Domains Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Switching Domains Broadcast Domains §A broadcast domain is the extend of the network where a broadcast frame can be heard. §Switches forward broadcast frames to all ports; therefore, switches do not break broadcast domains. §All ports of a switch, with its default configuration, belong to the same broadcast domain. §If two or more switches are connected, broadcasts are forwarded to all ports of all switches, except for the port that originally received the broadcast. § 1.2.2.2 Broadcast Domains Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Switching Domains Alleviating Network Congestion §Switches help alleviating network congestion by: §Facilitating the segmentation of a LAN into separate collision domains §Providing full-duplex communication between devices §Taking advantage of their high-port density §Buffering large frames §Employing high-speed ports §Taking advantage of their fast internal switching process §Having a low, per-port cost 1.2.2.4 Alleviating Network Congestion Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Chapter 1: Summary §In this chapter, you learned: §The trend in networks is towards convergence using a single set of wires and devices to handle voice, video, and data transmission. §There has been a dramatic shift in the way businesses operate. §There are no physical offices or geographic boundaries constraints. Resources must now be seamlessly available anytime and anywhere. §The Cisco Borderless Network architecture enables different elements, from access switches to wireless access points, to work together and allow users to access resources from any place at any time. Chapter 1 Summary Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png Chapter 1: Summary (cont.) §The traditional, three-layer hierarchical design model divides the network into core, distribution, and access layers, and allows each portion of the network to be optimized for specific functionality. §It provides modularity, resiliency, and flexibility, which provides a foundation that allows network designers to overlay security, mobility, and unified communication features. §Switches use either store-and-forward or cut-through switching. §Every port on a switch forms a separate collision domain allowing for extremely high-speed, full-duplex communication. §Switch ports do not block broadcasts and connecting switches can extend the size of the broadcast domain, often resulting in degraded network performance. § Chapter 1 Summary Presentation_ID ‹#› © 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential Rev08_Cisco_BrandBar10_060408.png CNA_largo-onwhite