Information About Failure And Recovery; Physical Installation; Redundancy; Maintaining The Network Links Versus Maintaining Sce 1000 Platform Functionality - Cisco SCE 1000 Installation And Configuration Manual

Chapter 3 Information About Topology

Information About Failure and Recovery

It is important to decide how the system should behave in case of the failure of the SCE 1000, both during
the time that the unit is down and after recovery. This decision is influenced by several factors:
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Physical Installation

In a link connection via an external optical splitter, SCE 1000 failure does not affect traffic flow, which
continues through the external optical splitter. When the SCE 1000 detects a failure that requires a
recover by reboot, it immediately switches to Cutoff mode, stopping all traffic flow over the link until
the SCE 1000 unit is restored to operation.
When operation resumes, the defined operational bypass mode is automatically resumed.
The configuration of a bump-in-the-wire installation depends on the remaining two factors.

Redundancy

Redundancy requires two platforms on parallel links, one active and one standby, in inline topology.
When the active SCE 1000 platform detects a failure situation, it will immediately switch to Cutoff
mode, causing the routers/switches on both ends to switch the traffic to the standby link and thus activate
the standby SCE 1000 platform.
There are two options when the failed SCE 1000 platform is finished reloading:
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Maintaining the Network Links Versus Maintaining SCE 1000 Platform
Functionality
When a single SCE 1000 is deployed, the user may decide that in case of a failure, maintaining the
network link is more important than providing the SCE 1000 functionality. In this scenario, when the
SCE 1000 detects a failure that requires a reboot process for recovering, it immediately switches to
Bypass mode, allowing all traffic to bypass the SCE 1000. The SCE 1000 stays in Bypass mode
maintaining the network link, albeit without SCE 1000 processing, until the SCE 1000 fully recovers
from the failure and is ready to resume normal functioning.
Alternatively, the user may decide that the SCE 1000 functionality is sufficiently crucial to require
severing the link if the SCE 1000 platform fails. In this case, when the SCE 1000 detects a failure that
requires a reboot process for recovering, it immediately switches to Cutoff mode, stopping all traffic
flow. The SCE 1000 stays in Cutoff mode, halting all traffic, until it fully recovers from the failure and
is ready to resume normal functioning. In Cutoff the physical interface is blocked, enabling the network
device connected to the SCE 1000 to sense that the link is down.
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Physical installation (connection mode)
Redundancy
Relative importance of maintaining connectivity vs. the continuity of the value-added services that
the SCE 1000 enables.
It may either actually resume operation in the defined operational bypass mode, returning to its
status as the active SCE 1000 platform.
It may remain inactive in the failure bypass mode.

Information About Failure and Recovery

Cisco SCE 1000 2xGBE Installation and Configuration Guide
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