Wan Card Redundancy; Cross-Connect Wan Card Redundancy Switching - Zhone IMACS 8000 User Manual

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WAN Card Redundancy

5.29 WAN Card Redundancy
Both T1 and E1 WAN redundancy are supported in cross-connect systems.
The cross-connect system allows 1:N redundancy with an WAN-R-T1 ow WAN-R-E1 WAN
in slot W4 protecting the WAN-T1 or WAN-E1 WANs in slot W1 through W3. Only WAN
cards with identical DSX, CEPT and/or CSU modules and configured the same are protected.
The WAN-R-T1 and WAN-R-E1 1:N redundancy protects against WAN card failure only, it
does not protect against T1/E1 facility failure. The WAN-R-T1 and WAN-R-E1 WAN card in
slot W4 must not have any T1/E1 connections as it will disturb the signal and cause a constant
CGA alarm to be logged.
WAN redundancy switching can be initiated by one of the following:
• A software command issued by the operator
• Removal of the active WAN card from the system
• Failure of the active WAN port or card
• CGA alarm declaration on the active WAN port or card
During a WAN redundancy switch, voice and data traffic are momentarily disrupted, and
transmission then recovers automatically.

5.29.1 Cross-Connect WAN Card Redundancy Switching

In cross-connect systems, WAN redundancy requires a WAN-R DUAL card in slot W4 (as
marked on its faceplate ejector). This card becomes a redundant card for the WAN cards in
slots W1 through W3 if it is equipped with matching DSX/CEPT, CSU, or HDSL modules,
and if those modules are installed in the same positions on both WAN cards. This protection
scheme is known as 1-in-N redundancy. When a switch occurs, a relay on the WAN-R card
switches the output of that card to the corresponding pins on the WAN connector of the
Interface card.
The following restrictions apply to cross-connect WAN redundancy:
You must install the WAN-R card in slot W4 for redundancy. If you install it in slot W1,
W2 or W3, it will work only as a standard WAN card with two ports.
For the 801x60 WAN series, if the plug-in modules on the WAN-R card do not match
those on a card in slot W1, W2, or W3, the WAN-R card will not behave as a backup for
that active WAN card. For the 801x70 WAN series, the strapping of the card must match
the WAN card that is being protected. The system will not reject the card, but it will not
switch even if the active WAN card fails. NOTE: Use of WAN 801x60 and 801x70 cards in
the same shelf is supported, however the 801470 card should be used in the WAN-R slot when
mixing cards. The 801x70 cards take longer to initialize then the 801x60 cards. In case the
IMACS shelf is restarted, the 801x60 cards will always come up faster then the 801x70 cards.
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