CHAPTER
6-1
Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09
6

Software Upgrade

This chapter explains how to upgrade the Cisco IOS image installed on the Cisco ASR 901 router.
Contents
Selecting a Cisco IOS Image
Upgrading the Cisco IOS image
Auto Upgrading the MCU
Manually Upgrading the ROMMON
Auto Upgrade of ROMMON

Selecting a Cisco IOS Image

When you select the Cisco IOS image for upgrade, consider the following:
Memory requirement—The router should have sufficient disk or flash memory to store the Cisco
IOS. The router should also have sufficient memory (DRAM) to run the Cisco IOS. The
recommended logging buffer in DRAM ranges from 8 kilobytes to 64 kilobytes. If the router does
not have sufficient memory (DRAM), the router will have boot problems when it boots through the
new Cisco IOS.
Interfaces and modules support—You must ensure that the new Cisco IOS supports all the interfaces
and modules in the router.
Software feature support—You must ensure that the new Cisco IOS supports the features used with
the old Cisco IOS.

Upgrading the Cisco IOS image

Complete the following steps to upgrade the Cisco IOS image:
Step 1 Download the Cisco IOS software image to the TFTP server.
Download the Cisco IOS software image onto your workstation or PC from the Download Software Area
(registered customers only).