CTC Union FRM220-NMC, User Manual, Page: 32 / 182

Chapter 3 Web Based Management
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Redundancy Mode
Caution:
Exercise extreme care and do not enable this mode unless you know what you are doing.
The redundancy feature is a special operation mode designed only for FRM220-10/100i in-band managed
cards. This mode allows the converter cards to be paired for redundancy. If either local or remote converter or fiber
becomes disconnected, the data path will fallback to the secondary converter/fiber pair. Referring to the following
diagram, each link requires two completely redundant converters and fiber links. The active link is shown in bold,
the standby link is grayed out. Note that any switch can be used as the NMC controls which path is active. A L2
switch with VLAN function or Spanning Tree is NOT required for this application.
Upon sensing a downed link, the alternate path is automatically promoted to the active state.
3.2 Fully redundant 10/100 media converter link
A fully loaded chassis can provide 9 pairs of redundant links. The screen graphic below shows the odd-even
channel pairing (in the highlighted bars). Only one channel in the pair will be active at any time. The pairs are 3-4,
5-6, 7-8, 9-10, 11-12, 13-14, 15-16, 17-18 and 19-20. These pairs are fixed and cannot be changed, so insert the
paired cards accordingly into the chassis. Slot 2 cannot be used in redundancy mode.
Switching will occur when NMC polling indicates an active 10/100i has experienced any fiber link, UTP link or FEF fault. The
switch over should occur within 6-10 seconds of actual fault occurrence. As traffic is switched to a different pair, any
connected switch will need to re-learn the MAC and generate new tables before normal filtering will be re-established.