On-Failure Mode Parameter - Cisco SCE 8000 Installation And Configuration Manual

Chapter 3 Cisco SCE 8000 Topology and Topology-Related Parameters

On-Failure Mode Parameter

The on-failure mode parameter configures the action taken by a failed box when a failure is detected.
As described in the
card supports three different modes. The Bypass and Cutoff modes are possible when the Cisco SCE
8000 is not operational because of platform failure or boot. The Forwarding mode enables control of
traffic flow and is not compatible with the non-operational status.
The following on-failure modes are possible:
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In a single Cisco SCE 8000 topology, the value of this parameter is determined by whether or not the
link can be completely cut when the Cisco SCE 8000 fails, or whether traffic flow should continue across
the link in spite of platform failure. In the latter case, the External-bypass mode is the recommended
setting, and is therefore the default value for the on-failure mode parameter.
In a dual cascaded Cisco SCE 8000 topology, the default on-failure mode is Bypass, because it preserves
full traffic processing functionality on both links in most single box failures (as long as the SPA interface
card is functioning properly).
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"Internal Bypass Mechanism" section on page
Bypass—The SPA interface card forwards traffic between the two ports of each link with no
intervention of the control application running in the Cisco SCE 8000 platform. This is also known
as 'electrical bypass'.
In a cascade setup, this allows the traffic of the link connected to the failed box to be passed to the
active box for processing.
Cutoff—There is no forwarding of traffic. The link is forced down, resulting in traffic cutoff at
Layer1.
External-bypass—The external optical bypass device is used to bypass traffic, maintaining link
continuity at all times.
Cutoff mode is suggested for the following:
Non-redundant inline topology if value-added services (such as security) are crucial and are
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more important than maintaining connectivity.
Bypass mode is suggested for the following:
Non-redundant inline topology if connectivity is of high importance.
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In redundant inline setups, if cutoff or traffic loss on a single link for a period of up to 10
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minutes (during a rare event of a SPA interface card failure) can be tolerated.
External-bypass mode is suggested for the following:
Non-redundant inline topology if connectivity is crucial.
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Redundant inline setups, if connectivity is crucial. When this mode is used, the link connected
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to the failed box is not serviced, and the other link operates with asymmetric routing
functionality.
3-11, the SPA Interface Processor
Cisco SCE8000 GBE Installation and Configuration Guide
On-Failure Mode Parameter
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