Brocade FastIron Ethernet Switch Administration Guide - Manual (Page 113)

Hitless Operating System (OS) Upgrade - An operating system upgrade and controlled switchover
without any packet loss to the services and protocols that are supported by Hitless management. The
services and protocols supported by Hitless management are listed in this section. Hitless failover and
hitless switchover are disabled by default.
Benefits of hitless management
The benefits of Hitless management include the following:
• The standby management module (the module that takes over the active role) and all interface
modules in the chassis are not reset
• Existing data traffic flows continue uninterrupted with no traffic loss
• Port link states remain UP for the duration of the hitless management event
• System configurations applied through Console/SNMP/HTTP interfaces remain intact
• Hitless switchover can be used by a system administrator, for example, to perform maintenance on a
management module that has been functioning as the active management module. Some
advantages of a hitless switchover over a hitless software reload are:
‐ A manual switchover is quicker, since the standby module does not have to reboot.
‐ Switched traffic through the Ethernet interfaces on the standby management module is not
interrupted.
NOTE
All traffic going through Ethernet interfaces (if present) on the management modules will be interrupted
during a hitless OS upgrade. This is because both management modules must be reloaded with the
new image. This applies to hitless OS upgrade only. It does not apply to hitless switchover or failover,
which does not interrupt traffic going through Ethernet interfaces on the standby management module
(the module that takes over the active role).
Supported protocols and services for hitless management events
The following table lists the services and protocols that are supported by Hitless management, and also
highlights the impact of Hitless management events (switchover, failover, and OS upgrade) to the
system’s major functions. The services and protocols that are not listed may be disrupted, but will
resume normal operation once the new active management module is back up and running.
Hitless-supported services and protocols - FSX 800
and FSX 1600 TABLE 12
Traffic type Supported protocols
and services Impact
Layer 2
switched
traffic,
including
unicast and
multicast
+
System-level
+
Layer 4
• 802.1p and 802.1Q
• 802.3ad - LACP
• 802.3af - PoE
• 802.3at - PoE+
• DSCP honoring and
Diffserv
• Dual-mode VLAN
• IGMP v1, v2, and v3
snooping
• IPv4 ACLs
• IPv6 ACLs
Layer 2 switched traffic is not
impacted during a Hitless
management event. All
existing switched traffic flows
continue uninterrupted.
New switched flows are not
learned by the FastIron
switch during the switchover
process and are flooded to
the VLAN members in
hardware. After the new
Benefits of hitless management
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