Cisco SCE 1000 2xGBE User's Guide download pdf (Page 43)

Chapter 2 Topology

Topology-Related Parameters

SCE 1000 2xGBE Release 2.0.10 User Guide

OL-7117-02 2-7

• Relative importance of maintaining connectivity vs. the continuity of the value-added services

that the SCE 1000 enables.

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:

• 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.

Maintaining the Network Links vs 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.

Topology-Related Parameters

Refer to the following sections to determine the correct values for all topology-related parameters

before beginning run the initial setup of the SCE 1000.

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Cisco SCE 1000 2xGBE User's Guide Page 43