| A | B |
|---|
| RAM | The router component that provides working storage for routing tables, ARP cache, fast-switching cache, packet buffering and packet hold queues. It is erased at shutdown. |
| NVRAM | The router component that stores the router's backup/startup configuration file. |
| Flash | The router component that holds the operating system image and microcode. |
| ROM | The router component that contains power-on diagnostics, a bootstrap program, and operating system software. |
| User EXEC Mode | A look-only router mode in which the user can view some information about the router but cannot make changes. |
| Privileged EXEC Mode | The router mode that supports the debuggin and testing commands, detailed examination of the router, manipulation of configuration files, and access to configuration modes. |
| Setup Mode | The router mode that presents an interactive prompted dialog at the console that helps the new user create a first-time basic configuration. |
| Global Configuration Mode | The router mode that implements powerful one-line commands that perform simple configuration tasks. |
| RXBOOT Mode | The router maintenance mode that you can use, among other things, to recover from lost passwords. |
| show version | The router command that displays the configuration of the system hardware, the software version, the names and sources of configuration files, and the boot image. |
| show processes | The router command that displays information about the active processes. |
| show protocols | The router command that displays the configured protocols; shows the status of all configured Layer 3 protocols such as IP, IPX and AppleTalk. |
| show memory | The router command that shows statistics about the router's memory, including memory free pool statistics. |
| show stacks | The router command that monitors the stack use of processes and interrupt routines and displays the reason for the last system reboot. |
| show buffers | The router command that provides statistics for the buffer pools on the router. |
| show flash | The router command that shows information about the Flash memory device. |
| show running-config | The router command that displays the active configuration file. |
| show startup-config | The router command that displays the backup configuration file. |
| show interfaces | The router command that displays statistics for all interfaces configured on the router. |
| show arp | The router command that displays the router's IP to MAC to Interface address mapping. |
| show cdp neighbors | The router command that displays the CDP updates on the local router. |
| show cdp interface | The router command that is used to display the values of the CDP timers, the interface status, and the encapsulation used by CDP for its advertisement and discovery fram transmission. |
| show cdp entry {device name} | The router command that is used to display a singel cached CDP entry. |
| telnet | The router command that provides a virtual terminal so administrators can use Telnet operations to connect with other routers running TCP/IP. |
| ping | The router command that sends a packet tothe destination host and then waits for a reply packet from that host. |
| trace | The router command that sends several packets and displays the round-trip time for each. |
| show ip route | The router command that is used to determine whether a routing table entry exists for the target network. |
| show interfaces serial | The router command that, most importantly, displays the line and data link protocol status. |
| Serial1 is up, line protocol is up | The router output that shows that the interface is completely operational. |
| Serial1 is administratively down, line protocol is down | The router output that shows that the interface is disabled. |
| Serial1 is up, line protocol is down | The router output that shows that there is a connection problem. |
| clear counters | The router command used to reset the counters to 0. |
| show commands | The group of commands that are used for router examination. |
| show sessions | The router command used to show the current telnet sessions on the router. |
