System information

Booting the Router

Book Title

3-18

• Booting: Router Partially Boots from Flash and Displays Boot Prompt

• Booting: Router Cannot Netboot from TFTP Server

• Booting: Router Cannot Netboot from Another Router

• Booting: Timeouts and Out-of-Order Packets Prevent Netbooting

• Booting: Invalid Routes Prevent Netbooting

• Booting: Client ARP Requests Timeout during Netboot

• Booting: Undeﬁned Load Module Error When Netbooting

• Booting: Router Hangs After ROM Monitor Initializes

• Booting: Router Is Stuck in ROM Monitor Mode

• Booting: Scrambled Output When Booting from ROM

• Booting: Local Timeouts Occur When Booting from ROM

• Booting: Unresponsive Terminal Connection to Unconﬁgured Access Server

Booting the Router

Cisco routers can initialize the system (boot) in four ways:

• Netboot—Routers can boot from a server using the Trivial File Transfer Protocol (TFTP), the

DEC Maintenance Operation Protocol (MOP), or the Remote Copy Protocol (RCP) across any

of the supported media types (such as Ethernet, Token Ring, Fiber Distributed Data Interface

[FDDI], High-Speed Serial Interface [HSSI], and serial lines).

• Flash memory—Routers can boot from Flash memory, a nonvolatile storage medium that can be

electrically erased and reprogrammed.

• ROM—Routers can boot a system from built-in read-only memory (ROM).

• PC Flash memory card—Routers can boot from a removable Flash memory card.

This section provides general information about router booting.

Netbooting Tips

During netbooting sessions, routers behave like hosts. They route via proxy Address Resolution

Protocol (ARP), Serial Line Address Resolution Protocol (SLARP) information, Internet Control

Message Protocol (ICMP) redirects, or a default gateway. When netbooting, routers ignore dynamic

routing information, static IP routes, and bridging information. As a result, intermediate routers are

responsible for handling ARP and User Datagram Protocol (UDP) requests correctly. For serial and

HSSI media, ARP is not used.

Before netbooting from a server, you should ping the server from the ROM software. If you cannot

ping the server, follow the procedures described in the section “Booting: Router Cannot Netboot

from TFTP Server” later in this chapter. If you still cannot ping the server, there is probably a server

conﬁguration or hardware problem. Refer to your TFTP server documentation or contact your

technical support representative for assistance.