Connecting to a Cisco Router

The 2501 router has two serial interfaces for WAN connection and one Attachment Unit Interface (AUI) connection for a 10 Mbps Ethernet network connection.  The 2501 router also has one console and one auxiliary connection via RJ-45 connectors.

In-Band management is the process of using your network for management of a device (EX: local subnet).Out-of-band management would be a modem dialing into a router’s auxiliary interface. The AUX port must be configured using the console port before it will function. A router contains five virtual terminal lines (0-4 VTY lines) to accept incoming Telnet sessions for in- band management. A Telnet session can also come from any interface. Every Cisco router has a console port that can be directly connected to a PC or terminal so that you can type commands at the keyboard and receive output on a terminal screen through a communications program, such as Hyper Terminal.

To set up out-of-band management with the connection between your terminal and the Cisco console port you need to do the following:

1. Cable the device using a rollover cable. You may need an RJ-45 to DB -9 or an RJ-45 to DB-25 adapter for your PC or terminal.
2. Configure terminal emulation with the following COM port settings: 9600bps,8 data bits, no parity,1 stop bit, and no flow control.

There are two configuration files for Cisco routers-one that is active and volatile (RAM), and one that the router uses to get configuration parameters during startup (stored in NVRAM).

A multi-protocol router maintains a separate routing table for each router protocol.

If a router does not know how to forward a packet, it will drop the packet. If it does know how to forward a packet, it changes the destination physical address to that of the next hop and transmits the packet. As the packet moves along the internetwork, its physical address changes but its protocol address remains constant. Routers each make independent routing decisions based on the local routing table. This is a hop-by-hop process, one step at a time.

Cisco routers have the ability to copy its configuration to and from a TFTP (Trivial File Transfer Protocol) server. This is normally used in a WAN for remote router configuration.

Cisco routers need at least four passwords set for minimal security: an enable password (primary router password),a console password, an auxiliary line password, and a VTY password (incoming telnet sessions).

Every Cisco router has a 16-bit configuration register, which is stored in a special memory location in NVRAM which allows the following functions: Force bootstrap program, select boot source, enable or disable the console break function, set terminal baud rate, load OS from ROM, and enable booting from TFTP.

“Router” is the default hostname for all Cisco routers; the character following the hostname tells you what mode you are in. The part of Cisco IOS that provides the user interface and interprets the commands you type is called the command executive, or EXEC. IP Routing must be manually configured.