FastIron Hardware Installation Guide for the FSX, FSX 800, and FSX 1600
6 - 8
© 2008 Foundry Networks, Inc.
December 2008
Layer 2 Hitless Switchover
FastIron SX 800 and SX 1600 chassis devices running software release 05.0.00 and later – L2, BL3, L3
Hitless switchover
is a CLI-driven switchover of the active and standby management modules without
interruption to switched traffic. In software releases that do not support hitless switchover (pre-release FSX
05.0.00), a manual switchover impacts the data traffic for the duration of the switchover and requires data flows to
be relearned.
This feature 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. The Layer 2 functions and protocols
supported by hitless switchover are the same as those supported for hitless OS upgrade (see “Layer 2 Hitless OS
Upgrade” on page 6-8 for a list).
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:
If the current active management module is physically removed from the chassis without first issuing the
switch-over-active-role
command, the standby module will still take over the active role, but the chassis will reset
and re-initialize all components. Thus, traffic going through the system will be interrupted.
For a description of the events that occur during a hitless switchover, see “What Happens During a Hitless OS
Upgrade and Hitless Switchover” on page 6-6.
For a description this feature’s impact to major system functions, see “How a Hitless OS Upgrade and Hitless
Switchover Impacts System Functions” on page 6-7.
Executing a Layer 2 Hitless Switchover
The CLI command for executing a hitless switchover is the same as for a switchover (non-hitless) in software
releases prior to FSX 05.0.00. See “Manually Switching Over to the Standby Management Module” on page 6-5.
Layer 2 Hitless OS Upgrade
Platform Support:
FastIron SX 800 and SX 1600 chassis devices running software release 05.0.00 and later –
L2, BL3, L3
Layer 2 Hitless OS upgrade
enables an upgrade of the operating system on a FastIron switch that has redundant
management modules, to software release FSX 05.0.00 or higher, without interrupting switched traffic for the
following Layer 2 features and protocols:
•
802.1p/q
•
802.1s MSTP
•
802.3ad - LACP
•
ACL accounting
•
ACL-based mirroring
•
All ports and links remain operational
•
BPDU Guard
•
Broadcast suppression (to uplink port only)
•
Dual-mode VLAN
•
Dynamic buffer allocation
