ch.1 – wans and routers
DESCRIPTION
Ch.1 – WANs and Routers. CCNA 2 version 3.0 Rick Graziani Cabrillo College. Note to instructors. If you have downloaded this presentation from the Cisco Networking Academy Community FTP Center, this may not be my latest version of this PowerPoint. - PowerPoint PPT PresentationTRANSCRIPT
Ch.1 – WANs and Routers
CCNA 2 version 3.0
Rick Graziani
Cabrillo College
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Note to instructors
• If you have downloaded this presentation from the Cisco Networking Academy Community FTP Center, this may not be my latest version of this PowerPoint.
• For the latest PowerPoints for all my CCNA, CCNP, and Wireless classes, please go to my web site:
http://www.cabrillo.cc.ca.us/~rgraziani/• The username is cisco and the password is perlman for all of
my materials.
• If you have any questions on any of my materials or the curriculum, please feel free to email me at [email protected] (I really don’t mind helping.) Also, if you run across any typos or errors in my presentations, please let me know.
• I will add “(Updated – date)” next to each presentation on my web site that has been updated since these have been uploaded to the FTP center.
Thanks! Rick
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Overview
Students completing this module should be able to:
• Identify organizations responsible for WAN standards
• Explain the difference between a WAN and LAN and the type of addresses each uses
• Describe the role of a router in a WAN
• Identify internal components of the router and describe their functions
• Describe the physical characteristics of the router
• Identify common ports on a router
• Properly connect Ethernet, serial WAN, and console ports
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Introduction to WANs
These are the major characteristics of WANs: • They connect devices that are separated by wide geographical areas. • They use the services of carriers such as the Regional Bell Operating
Companies (RBOCs), Sprint, MCI, VPM Internet Services, Inc., and Altantes.net.
• They use serial connections of various types to access bandwidth over large geographic areas.
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Introduction to WANs
• Routers offer many services, including internetworking and WAN interface ports. • Switches in the WAN provide connectivity for voice, data, and video
communication. • Modems include interface voice-grade services, channel service units/digital
service units (CSU/DSUs) that interface T1/E1 services, and Terminal Adapters/Network Termination 1 (TA/NT1s) that interface Integrated Services Digital Network (ISDN) services.
• Communication servers concentrate dial-in and dial-out user communication.
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Introduction to WANs
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Introduction to routers in a WAN
Routers connect and allow communication between two networks and determine the best path for data to travel through the connected networks.
RAM
• Stores routing tables
• Holds ARP cache
• Holds fast-switching cache
• Performs packet buffering (shared RAM)
• Maintains packet-hold queues
• Provides temporary memory for the configuration file of the router while the router is powered on
• Loses content when router is powered down or restarted
NVRAM
• Provides storage for the startup configuration file
• Retains content when router is powered down or restarted
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Introduction to routers in a WAN
Flash memory• Holds the operating system image (IOS) • Allows software to be updated without removing
and replacing chips on the processor • Retains content when router is powered down or
restarted • Can store multiple versions of IOS software • Is a type of electronically erasable,
programmable ROM (EEPROM) Read-only memory (ROM) has the following
characteristics and functions: • Maintains instructions for power-on self test
(POST) diagnostics • Stores bootstrap program and basic operating
system software • Requires replacing pluggable chips on the
motherboard for software upgrades
Interfaces • Connect router to network for
frame entry and exit • Can be on the motherboard
or on a separate module
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Router LANs and WANs
• Smaller broadcast domains
• Connecting Layer 3 networks
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Router LANs and WANs
• Routers are the backbone devices of large intranets and of the Internet.
• They operate at Layer 3 of the OSI model, making decisions based on network addresses.
• The two main functions of a router are the selection of best path for and the switching of frames to the proper interface.
• Routers accomplish this by building routing tables and exchanging network information with other routers.
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Router role in a WAN
• The WAN physical layer describes the interface between the data terminal equipment (DTE) and the data circuit-terminating equipment (DCE).
• Generally, the DCE is the service provider and the DTE is the attached device. In this model, the services offered to the DTE are made available through a modem or a CSU/DSU.
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Router role in a WAN
• The primary WAN roles of a router are therefore not routing, but providing connections to and between the various WAN physical and data-link standards.
• For example, a router may have an ISDN interface using PPP encapsulation and a serial interface terminating a T1 line using Frame Relay encapsulation.
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Academy approach to hands-on labs
• In the academy lab, devices that make up the WAN cloud are simulated by the connection between the back-to-back DTE-DCE cables.
• One of the routers will provide the clock rate (later).
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Router internal components
• CPU • RAM • Flash • NVRAM
• Buses • ROM • Interfaces • Power Supply
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Router physical characteristics
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Router external connections
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Management port connections
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Management port connections
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Connecting console interfaces
When connected using the console interface, the computer is acting as a “dumb terminal”.
<Router Output>
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Connecting console interfaces
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Connecting LAN interfaces
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Connecting WAN interfaces
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Connecting WAN interfaces
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Connecting WAN interfaces
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Summary
An understanding of the following key points should have been achieved:
• WAN and LAN concepts
• Role of a router in WANs and LANs
• WAN protocols
• Configuring encapsulation
• The identification and description of the internal components of a router
• The physical characteristics of a router
• The common ports on a router
• How to connect router console, LAN, and WAN ports