Product specifications

Chapter 4: System Management Efficient Networks
®
Router family
Technical Reference Guide
Page 4-34 Efficient Networks
®
Spanning Tree
The Spanning Tree algorithm allows a bridge to dynamically discover the subnet
topology and create a loop free path. When Spanning Tree is enabled, the bridge will
transmit configuration Bridge Protocol Data Units (PDUs) to other bridges and from
the information received, determine a "root" bridge and a "destination" bridge. When
this information is combined with distance calculations, it allows the bridge to
determine the optimum way to forward frames. When the optimum route is
determined, the other bridge interface is shut down to avoid creating loops.
The Spanning Tree mode is persistent across reboots, but will be disabled if the ATM
interface has any error at boot time. Deleting a virtual connection removes it from
participating in the Spanning Tree calculations.
Boot Code Options
The router provides a number of options for booting router software.
You can boot from the routers flash memory, the most common option.
Or, you can boot across the LAN network from a TFTP server, perhaps to
test a new level of router software before downloading it to flash memory.
You can also boot through a gateway to a WAN. The router allows you to set
permanent network boot parameters used during network booting, and it
enables you to temporarily override those parameters.
Finally, the router lets you define the order in which the router boot
procedures are performed. You can make changes to the boot procedures
and specify network boot parameters by entering manual boot mode.
The next section describes the purpose and functions of the boot code. The section
following it, Manual Boot Mode on page 4-36, describes a menu of manual boot
options.
NOTE:
For routers with a reset button, see Manual Boot Mode on page 4-36.
What is the Boot Code?
The boot code is responsible for initializing the hardware from an initial power up state
and then transferring control to the operating system (kernel).