Alcatel-Lucent omni 6600 User Manual

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OmniSwitch 6600 Family
Availability Features
OmniSwitch 6600 Family Hardware Users Guide
September 2006
page 1-3
Availability Features
The switch provides a broad variety of Availability features. Availability features are hardware- and 
software-based safeguards that help prevent the loss of data flow in the unlikely event of a subsystem fail-
ure. In addition, some Availability features allow you to maintain or replace hardware components with-
out powering off your switch or interrupting switch operations. Combined, these features provide added 
resiliency and help ensure that your switch is consistently available for your day-to-day network opera-
tions.
Hardware-related Availability features include:
Smart Continuous Switching
In stacked configurations, one OmniSwitch 6600 Family switch is designated as the primary “manage-
ment module” for the stack. Because the stack can be thought of as a virtual chassis, the role of this 
primary management switch is to monitor and manage the functions of the stack. 
Similar to chassis-based switches such as the OmniSwitch 7700 and Omniswitch 7800, the stack also 
allows users to assign an additional switch as a secondary management module. As with the OS7700 and 
OS7800, the stack’s secondary switch immediately takes over management functions in the event of a 
primary switch failure.
All other switches in the stack are considered idle, and act very much like Ethernet Network Interface 
(ENI) modules in OS7700 and OS7800 switches, in that they provide Ethernet ports for 10/100 traffic. 
The stack provides support for all idle switches during primary-to-secondary failover. In other words, if 
the stack’s primary switch fails or goes offline for any reason, all idle switches will continue data trans-
mission during the secondary switch’s takeover process. This Availability feature is referred to as Smart 
Continuous Switching
.
Incoming Layer 2 packets will continue to be sent to the appropriate egress port during failover. Spanning 
Tree will continue handling BPDUs received on the switch ports, as well as port link up and down states. 
The Spanning Tree topology will not be disrupted.
Note. Smart Continuous Switching is designed to maintain data flow only during primary/secondary 
switch failover and is not intended to support long-term data flow. If both the primary and secondary 
switches in the stack go offline, switch operations (including all 10/100 support) will be disabled.
For more information on primary, secondary, and idle switches, as well as the failover process, refer to