Cisco Cisco Packet Data Gateway (PDG) Documentation Roadmaps
Packet Data Interworking Function Overview
▀ Features and Functionality - Licensed Enhanced Feature Support
▄ Cisco ASR 5000 Series Product Overview
OL-22937-01
Online Upgrade
The customer has the benefits of upgrading software from a fully redundant device without the expense of maintaining a
fully loaded, fully redundant ASR 5000 in a permanent state of standby.
fully loaded, fully redundant ASR 5000 in a permanent state of standby.
The PDIF supports online software upgrades with a single software version difference between two chassis. For
example, upgrading from Release 8.1 to 8.2 is supported. Support for a chassis running greater differences in software
versions would be qualified by Cisco on an as-needed basis.
example, upgrading from Release 8.1 to 8.2 is supported. Support for a chassis running greater differences in software
versions would be qualified by Cisco on an as-needed basis.
Important:
Refer to the Maintenance chapter in this guide for information on how to perform the upgrade.
The online upgrade process calls for a spare ASR 5000 to temporarily perform the services currently being provided by
a live networked chassis and upgrade the software with minimal service interruption. This model is called Active-
Standby, as one chassis is designated as active and the other as standby. The standby chassis does not handle any new,
incoming sessions because the DNS allocating new sessions does not know about the backup chassis. The backup is
only required to handle sessions that were already on the primary chassis when it was administratively disconnected
from the DNS server. Except for the data loss during the brief chassis switch-over, the session information (accounting
and timers) are synchronized so that they are accurate when the backup becomes the active PDIF.
a live networked chassis and upgrade the software with minimal service interruption. This model is called Active-
Standby, as one chassis is designated as active and the other as standby. The standby chassis does not handle any new,
incoming sessions because the DNS allocating new sessions does not know about the backup chassis. The backup is
only required to handle sessions that were already on the primary chassis when it was administratively disconnected
from the DNS server. Except for the data loss during the brief chassis switch-over, the session information (accounting
and timers) are synchronized so that they are accurate when the backup becomes the active PDIF.
Important:
Online upgrade requires miscellaneous internal processing that may result in intensive CPU
utilization. Up to 50% CPU utilization overhead should be expected during the upgrade.
The Active-Standby Upgrade Model
The Active-Standby model is shown below: