Cisco ASR1002-5G-SHA/K9 Software Guide - Page 64

ISSU Upgrade for Redundant Platforms Chapter 4 Software Upgrade Process ISSU Upgrade for Redundant Platforms ISSU represent a full or partial software upgrade of a system from one version to another with minimal outage on the forwarding plane (minimal packet loss) and no outage on the control plane. This section covers the following topics: • Overview of ISSU on the Cisco ASR 1000 Series Routers, page 4-2 • Prerequisites for ISSU, page 4-4 • Restrictions for ISSU, page 4-5 • ISSU Upgrade Procedures, page 4-5 • In Service One-Shot Software Upgrade Procedure, page 4-73 • ISSU Procedures (Prior to Cisco IOS XE Release 2.1.2), page 4-73 Overview of ISSU on the Cisco ASR 1000 Series Routers For the Cisco ASR 1000 Series Routers, ISSU-compatibility depends on the software subpackage being upgraded and the hardware configuration. Consolidated packages are ISSU-compatible in dual RP configurations only and have other limitations described later in this document. Some RP and ESP software subpackages can be upgraded in service even in single RP or ESP hardware configurations via dual IOS processes running on the RP; others require dual RP or ESP configurations for an ISSU upgrade. The SPA and SIP software subpackages must be upgraded on a per-SPA or per-SIP basis. See Table 4-1 to view an In Service table that addresses the contexts where limited interruption upgrades can be performed. If you are updating multiple subpackages, you should also realize that the sequence of the upgrade is important to minimize router downtime for the software upgrade (see the "Using ISSU to Upgrade SubPackages (Prior to Cisco IOS XE Release 2.1.2)" section on page 4-74). The specific procedures in this document represent supported and tested installation sequences. The Cisco IOS XE system software allows other installation sequences for special purposes under the guidance of Cisco customer support representatives, but the steps in this document should be followed otherwise. These steps should be followed completely, as the Cisco ASR 1000 Series Routers are designed to run one version of Cisco IOS XE for all consolidated packages and subpackages on an RP, and running subpackages from different versions of Cisco IOS XE can cause unexpected router behavior. When performing ISSU upgrades on the Cisco ASR 1000 Series Routers, it is important to remember that minimal interruption upgrades can be performed using either the issu command set or the request platform command set, and that either command set can be used to perform limited interruption individual consolidated package or subpackage upgrades. Note ROMmon images are downloaded separately from Cisco IOS XE images and have their own installation procedures, and are therefore not mentioned as part in this document as part of the ISSU upgrade procedure. Table 4-1 provides a list of the Cisco ASR 1000 Series Routers subpackages and whether or not they can be upgraded without losing any network traffic in single and dual RP and ESP configurations using ISSU. Cisco ASR 1000 Series Aggregation Services Routers Software Configuration Guide 4-2 OL-16506-10