Router Configuration Basics

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Router Configuration Basics
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2
CISCO Router Hardware

• Model 2621 2621XM
• Two LAN ports
• 10/100 autosensing Ethernet
• Two network module slots
• Two WAN slots
• One wide area interface card (WIC-2T)
• with two serial ports
• Processor
• 2621 Motorola MPC860, 50 MHz
• 2621 Motorola MPC860P
• Memory
• RAM - 24MB to 130MB depending on router
• NVRAM - 32KB
• Flash - 8MB to 32MB depending on router

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Interfaces

• Fastethernet 0/0 - LAN (note slot/port)
• Fastethernet 0/1 - LAN
• Serial 0/0 - WAN
• Serial 0/1 - WAN
• Console port
• Direct connection
• Configuration
• Auxiliary port
• Modem connection
• Configuration

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Router Software

• CISCO Internetwork Operating System (IOS)
• Version 12
• Command line interface
• Supports IP/IPX/AT/DEC

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IOS Modes

• User
• Display info
• Privileged
• Change configuration
• Global configuration
• One-line commands that affect router globally
• Specific configuration
• Detailed multi-line configuration
• Setup dialog
• Interactive prompts for quick configuration
• ROM monitor
• Bootstrap program (may be used for diagnostics
  and recovering passwords), enter with CtrlBreak
  at boot time
• RxBOOT
• Limited IOS in ROM used for maintenance, prompt
  is hostname (boot)

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Memory Components

• ROM
• Power on self test (POST)
• Bootstrap program
• Subset of IOS
• NVRAM
• Nonvolatile RAM
• Startup configuration
• Backup of active configuration

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Memory Components

• Flash RAM
• Reprogrammable
• Holds IOS
• May hold multiple versions
• RAM
• Temporary storage
• Active (running) configuration
• Routing table, ARP cache, etc.

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Cables

• Ethernet patch cable
• LAN connection
• Straight-through cable
• Cross-over cable
• Serial cable
• WAN connection
• Smart serial connector (small)
• V.35 connector
• Connects to DSU/CSU
• High-speed synchronous data exchange standard
• T1 leased lines for example

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Cables

• Flat rollover cable
• Console connection (RS232 protocol)
• Connect to COM port of PC
• We use USB-to-RS232 adapter
• Proper pin-outs for serial connection to COM port
  of PC
• USB-to-RS232 Adapter
• Console connection
• Used with flat rollover cable for console
  connection
• Allows use of USB port rather than COM port

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Boot Sequence

• Hardware test
• Load IOS
• Apply configuration

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Boot Sequence Details

• POST routines
• ? ROM
• Bootstrap program
• ? ROM
• IOS loaded
• ? Flash, TFTP server, ROM (subset)
• Configuration executed
• ? NVRAM, TFTP server, console

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Configuration Locations

• Console
• Initially
• Modem via AUX port
• Virtual terminal (telnet) via network
• TFTP server
• Network management station

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Prompts

• User mode
• Routergt
• Privileged mode
• Router
• Global configuration mode
• Router(config)
• Specific configuration mode
• Router(config-xx)

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Basic Commands

• ?
• Help
• show version
• Hardware
• Uptime
• IOS version
• enable
• Privileged mode

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Basic Commands

• config terminal
• Global configuration
• erase startup-config
• Delete backup configuration in NVRAM
• reload
• Warm boot

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Basic Commands

• show startup-config
• Show configuration file in NVRAM
• show running-config
• Show active configuration
• copy running startup
• Save active configuration
• Ctrl/C
• Break

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Basic Commands

• Up-arrow
• Command history
• exit
• Exit current mode
• Logout

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End