Users Guide

In-Service Software Upgrade

This chapter deals with In-Service Software Upgrade (ISSU) and its dependencies.

Topics:

• ISSU Introduction

• Fastboot 2.0 (Zero Loss Upgrade)

• L2 ISSU

• L3 ISSU

• CoPP

• Mirroring flow control packets

• PFC

• QoS

• Tunnel Configuration

ISSU Introduction

In-service software upgrades (ISSU), also known as warmboot or fastboot 2.0, allow Dell EMC Networking to address software

bugs and add new features to switches and routers without interrupting network availability. An ISSU eliminates the need to

reboot the entire device. Dell EMC Networking offers ISSU on some switches currently. Generally an ISSU requires a network

device with redundant control plane elements, such as supervisor engines or routing engines. This redundancy allows us to

update the software image on one engine while the other maintains network availability. In Dell EMC Networking switches, the

current configuration runs on the NPU while the system reboots the CPU, this procedure is known as warmboot.

Warmboot Limitations

Warmboot will not work if the following items were changed during the current running configuration:

● Changes in cam-profile

● Changes in cam-acl-vlan

● Changes in ip ecmp-group maximum-path

● Changes in cam-ipv6-extended-prefix

● Enabling / disabling feature aclrange

● Enabling feature vrf

● Changes in ALP mode

● Stack-unit re-numbering

Fastboot 2.0 (Zero Loss Upgrade)

This feature has been designed to ensure that there is no traffic loss during upgrade of a switch to a different image or while

doing a reload via warmboot.

The user will need to configure the boot-type to warmboot under the reload-type configuration mode. All the supported feature

information gets stored in a persistent storage, and when the switch goes in for a reload, all hardware programmed entries in

CAM and FIB will be saved and traffic will be treated seamlessly, during reload. After the reload is complete, the running-config

and startup-config will be compared and if there is a difference, the device will be programmed based on the startup-config.

474 In-Service Software Upgrade