Alcatel-Lucent Omni 6624 - Manual (Page 15)

OmniSwitch 6600 Series Availability Features
OmniSwitch 6624/6648 Hardware Users Guide April 2004 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
• Software Rollback
• Hot Swapping
• Hardware Monitoring
Smart Continuous Switching
In stacked configurations, one OmniSwitch 6600 series switch is designated as the primary “management
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
Chapter 3, “Managing OmniSwitch 6600 Series Stacks.”