| A | B |
|---|
| ROM | power-on diagnostics, bootstrap, OS software |
| NVRAM | stores router's backup/startup config file |
| Flash | holds the OS image |
| RAM | stores routing tables, ARP cache, running config |
| interfaces | where packets enter and exit router |
| User EXEC mode | limited examination of router |
| global configuration mode | enter simple configuration commands |
| privileged EXEC mode | detailed examination of router, debugging, and testing |
| SETUP mode | mode used to establish initial, limited configuration |
| modem | connects via auxiliary port to provide external config source |
| console | primary configuration source; port used to configure initially |
| RXBOOT | mode used to recover from a catastrophe |
| enable | command to gain access to privileged mode |
| router(config)# | global configuration mode |
| show startup-config | displays the backup or startup file stored in NVRAM |
| show version | displays info about the current IOS, such as the version being used |
| router(config-if)# | interface configuration mode |
| show protocols | displays the router's configured protocols, like IP, IPX, and AppleTalk |
| CDP | Cisco's proprietary data link protocol |
| directly-connected routers | CDP provides information about these to network admins |
| show cdp commands | display information about neighboring routers |
| Telnet sessions | Up to five allowed; can use a show command to display current sessions |
| show ip route | to see routing table and if specific entries exist |
| show interfaces serial | displays serial line and data link protocol status...should both be "up" |
| show interfaces | displays info about interfaces...E0, S1, etc |
| show running-config | displays the active config file running from RAM |
| trace | command that displays the path taken by packets |
| ping | command to test end-to-end at network layer |
| show memory | displays info about the router's memory like memory free pool stats |
| clear counters | resets counters to get more accurate picture of network |
