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Chapter 3 Cisco SCE8000 Topology and Topology-Related Parameters
Topology-Related Parameters
The connection mode parameter is determined by the physi cal deployment of the Cisco SCE8000, as
follows:
• Single Cisco SCE8000 inline installation = Inline connection mode.
• Single Cisco SCE8000 optical splitter installation = Receive-only connection mode.
• Two-platform cascaded Cisco SCE8000 inline installation = Inline-cascade connection mode.
• Two-platform cascaded Cisco SCE8000 optical splitter installation = Receive-only-cascade
connection mode
Physically Connected Links Parameter
A cascade topology supports two traffic links. This parameter defines which link is connected to which
Cisco SCE8000 platform. The links are designated as follows:
• Link 0
• Link 1
Priority
In a cascade topology, the user must define the priority of each Cisco SCE8000.
• Primary — The Primary Cisco SCE8000 is active by default
• Secondary — The Secondary Cisco SCE8000 is the default standby.
Note that these defaults apply only when both devices are started together. However, if the primary
Cisco SCE8000 fails and then recovers, it will not revert to active status, but remains in standby status,
while the secondary device remains active
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 section Internal Bypass Mechanism, page 3-9, the SPA Interface Processor card
supports three different modes. The Bypass and Cutoff modes are possible when the Cisco SCE8000 is
not operational due to 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:
• 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 SCE8000 platfo rm. 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.