User guide

Metrobility “redundant twister” 5
Overview
The Metrobility “redundant twister” offers the resiliency of data link
redundancy to ensure network integrity with no down time. This link duplication
provides the nonstop networking capability essential for high priority traffic and
mission-critical applications. The “redundant twister” is a 100BASE-TX to TX/FX
or 10BASE-T to 10BASE-T device that provides full redundant data paths. In
Dynamic Recovery Mode (DRM), the “redundant twister” actively monitors the
primary link and if it fails, automatically activates the secondary link without
interruption to network operation.
The “redundant twister” has the following features:
• Immediately switches over from the primary to the secondary link if the
primary link fails.
• Supports full- and half-duplex operation.
• Provides redundant power to ensure no down time.
• Can be configured to operate in Dynamic Recovery Mode (DRM) to ensure
session integrity and increased uptime. (2711-11 only)
• Can be configured to operate in Network Select Mode (NSM) to redirect and
isolate traffic adding extra security. (2711-11 only)
• Fast Ethernet models demonstrate a maximum loss of 2-3 packets (measured
with minimum packet size and minimum inter-packet gap) due to fail-over
transition.
• Can be configured to return automatically to the primary link after the failure
condition is resolved.
• Provides minimal impact on the round trip delay for communication in half-
duplex collision domains.
• Link Loss Carry Forward
*
enable/disable functionality. (2711-11 only)
• Can be configured to operate with auto-negotiating devices.
• The twisted-pair ports on the 2711 are equipped with an MDI-II to MDI-X
switch eliminating the need for crossover cables.
* Refer to the page titled “Link Loss Carry Forward (LLCF)” in the User Guide section of this document for
more detailed information.