Setup 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 ow control packets
• PFC
• QoS
• Tunnel Conguration
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 oers 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 conguration 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 conguration:
• Changes in cam-prole
• 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 trac loss during upgrade of a switch to a dierent image or while doing a reload
via warmboot.
The user will need to congure the boot-type to warmboot under the reload-type conguration 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
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528 In-Service Software Upgrade