Cisco Systems 1000 Series User Manual

For the request platform command set, the request platform software package install rp slot commit 
command must be entered to stop the rollback timer only in cases where the auto-rollback option is 
used.

The rollback timer for the issu command set can be configured by entering the issu set rollback-timer 
command. The rollback timer when used with the request platform command set is specified when you 
use the auto-rollback option when entering the issu request platform software package install 
command.

For ISSU upgrades on Cisco ASR 1000 Series Routers, it may be advisable to set long rollback times 
when the upgrade is being performed on routers with large configurations.

The amount of time left on the rollback timer during an ISSU upgrade can be checked by entering the 
show issu rollback-timer command.

To complete a software upgrade of an individual subpackage using dual IOS processes on a single RP,  
SSO must first be enabled.

Software upgrade with dual IOS processes is useful for upgrading the individual RP subpackages that 
can be upgraded without a router reload. See 

 for a list of these subpackages. Importantly, note 

that most subpackage upgrades in a single RP configuration require a hardware reload to complete 
(whether an RP reload for an RP subpackage, an ESP reload for the ESPBase subpackage, a SIP reload 
for a SIPBase subpackage, or a SPA reload for the SIPSPA subpackage), so limited interruption upgrades 
for single RP configurations are not available in most upgrade scenarios.

For information on configuring a second IOS process on a single RP, see the 

When upgrading the Cisco IOS XE operating system software using the ISSU process, it is important to 
determine the compatibility of the upgraded software to your current software and hardware. The ISSU 
process allows software to be updated or otherwise modified while packet forwarding continues with 
minimal interruption. 

Cisco IOS XE release compatibility using the ISSU process utilizes the SSO functionality to preserve 
state while software versions on the router differ, as during an upgrade. Most SSO-capable features in 
each Cisco IOS XE release are ISSU capable. ISSU is only supported if SSO is enabled in the 
configuration and the system is in a steady state (SSO ready state has been achieved). ISSU compatibility 
depends on the set of specific feature clients that are in use and whether they support ISSU. All ISSU 
upgrades include at least one IOS switchover operation. It is important to understand which features are 
in use and whether these features are ISSU compatible.

 Cisco ASR1006 or ASR 1013 series routers are hardware-redundant chassis. The hardware-redundant 
chassis has two ESP linecards and two RPs which exchange state using hardware links. The Cisco 
ASR1002 and ASR1004 Series Routers are not hardware redundant, but are software-redundancy 
capable. The nonredundant chassis has a single RP and a single ESP, but allows the operation of up to 
two IOS processes on the single RP to exchange states locally.