Cisco BPX 8600 Series, Руководство по установке и настройке

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Cisco BPX 8600 Series Installation and Configuration
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
Chapter 26 Configuring SONET Automatic Protection System
APS 1+1 (Card and Line Redundancy)
•
The APS backcards are inserted into the APS redundant backplane assembly.
• The working lines on the backcard must be connected to the same slot as the primary front card
• The protection lines connected to the same slot as the secondary front card.
The switching of the front cards is controlled by switch software under the Y-redundancy protocol. The
switch software performs switching between the two cards in the event of a front card failure, front card
downed, front card failing self-test, and so on.
You may add APS at any time after Y-redundancy is configured as long as the protection line is in the
standby state. You may add APS even if lines and trunks are upped and the card is passing traffic.
Note Normally when APS and card redundancy are implemented together, the term YRED
really means card redundancy, as in this case there is no Y-cabling involved. An exception
exists when the BXM is attached to a MGX 8220 (feeder shelf) or other device which does
not support APS. In that case, Y-cables or straight cables may be used with APS.
When APS is configured on a card pair, switch software checks to ensure that both cards match and
support APS.
For APS 1+1 redundancy, the same numbered ports on adjacent BXM backcards are used. The
maximum number of connections supported does not change, as the complete connection capability of
the cards is available.
Note Using only one front card and two backcards is not a valid configuration when adding APS
capability, and the APS alarm capability is reduced when the standby card is not available.
Application Notes for APS 1+1
Using switchcdred/switchyred command
Note
Entering switchcdred or switchyred execute the same command. The newer name is
switchcdred which replaces switchyred, but switchyred may still be used for those
familiar with that command.
The switchcdred (switchyred) command can be used to switch between an active and standby front
card in an APS 1+1 configuration. For example, you might want to do this to test the standby front card.
Following a switchcdred (switchyred), or active card reset, the BXM card is sent a message from
switch software to have it perform an APS switch to align itself with the last user switchapsln switch
request.
If the last user request is “clear”, full automatic APS switching is in effect with the working line in the
active state by default. When there is no last user switch request to switch any particular line (that is,
protection line), the working line becomes active.