Bypass Mechanism - Cisco SCE 1000 Installation And Configuration Manual

Chapter 3 Information About Topology
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Bypass Mechanism

The SCE 1000 includes a Network Interface Card with a bypass mechanism that is enabled upon
SCE 1000 failure. In addition, when connected in-line it can also be enabled in normal operation to
simultaneously bypass traffic flow to the other side and direct it internally for analysis. In this case it
maintains "receive-only"-like monitoring functions, when control functionality is not required.
The bypass card supports the following four modes:
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Watchdog mechanism. There are two types of watchdogs:
HW watchdog. A hardware mechanism that detects control entity failure.
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SW watchdog. A software mechanism that periodically checks for software failures in the
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SCE 1000. If a failure is detected, an error massage is sent and the SCE 1000 reboots.
Run time hardware tests. The system periodically tests the hardware components for error. If a
hardware component is malfunctioning, it will be discovered by the system within seconds.
Bypass — The bypass mechanism preserves the network link, but traffic is not processed for
monitoring or for control.
Forwarding — This is the normal operational mode, in which the SCE 1000 processes the traffic for
monitoring and control purposes.
Sniffing — The bypass mechanism preserves the network link, while in parallel allowing the
SCE 1000 to process the traffic for monitoring only.
Cutoff — There is no forwarding of traffic, and the physical link is forced down (cutoff functionality
at layer 1).
Cisco SCE 1000 2xGBE Installation and Configuration Guide
Bypass Mechanism
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