APPENDIX SCE 2000, Руководство пользователя

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A-2
Cisco SCE 2000 4xGBE Installation and Configuration Guide
OL-21096-02
Appendix A The External Optical Bypass Module
External Optical Bypass Functionality
External Optical Bypass Functionality
The External Optical Bypass module is connected bump-in-the-wire in the GBE link. It is then connected
to the SCE 2000 platform with two types of connections:
•
GBE optical connections for data link traffic — GBE connections from the External Optical Bypass
module to one pair of the GBE line ports.
• Power and Control connection — Connection to a dedicated connector on the SCE 2000 platform
back panel, so the SCE 2000 platform can provide power to the External Optical Bypass module.
(Note that the power connection also provides the logical control functionality.)
The External Optical Bypass module is normally inactive, (not in bypass), and simply transfers the two
GBE signals to and from the SCE 2000 platform.
In case the SCE 2000 platform stops providing power to the External Optical Bypass module, or in case
the power cable is disconnected from the optical bypass module, the External Optical Bypass module
becomes active, bypassing the two GBE links to the SCE 2000 platform, and thus preserving network
connectivity.
Figure A-3 illustrates the operation of the bypass module when it is inactive (not in bypass). The data
traffic is simply transferred through the bypass module to the SCE 2000 platform.
Figure A-1 Operation of the Bypass Module When Inactive
Figure A-4 illustrates the operation of the bypass module when it is active (in bypass). The data traffic
flows through the bypass module, and the GBE link no longer includes the SCE 2000 platform. Note that
when the bypass module is active, it puts the SCE 2000 platform into a loop connection, creating a
shortcut between the SCE 2000 platform GBE interfaces.
Sub
Tx Rx
Net Control No Bypass
Tx Rx
Router Switch
External optical
bypass module
SCE 2000 4xGBE
LINK RX
Cisco SCE 2
000 Series
4xGBE
TX
RX MM
TX
LINK RX TX
RX MM
TX
LINK RX TX
RX MM
TX
LINK RX TX
RX MM
TX
GBE-1 SUB
LINE NET
PWR B STAT US
PWR A
BYPASS
10/100/
1000
LINK/ ACTIVE
10/100/ 1000
LINK/
ACTIVE
GBE-2 SUB LINE/CA
SCADE NET
AUX
CONSOLE
MNG 2 MNG 1
92808