Dual Cisco Sce 8000 Topology (Cascade) - Cisco SCE 8000 Installation And Configuration Manual

Dual Cisco SCE 8000 Topology (Cascade)

Dual Cisco SCE 8000 Topology (Cascade)
In this topology, two cascaded Cisco SCE 8000s are used. This allows a switchover solution, where in
case of a failure of one Cisco SCE 8000, the functionality that the Cisco SCE 8000 provides is preserved
by the redundant platform (see
This topology allows both control and monitoring functionality where redundancy is required and
"inline" connection is used. The two Cisco SCE 8000s are cascaded, so the primary Cisco SCE 8000
processes the traffic of the two links, while the secondary Cisco SCE 8000 only bypasses the traffic of
its links to the primary Cisco SCE 8000 for processing, and then bypasses the processed traffic back to
the link. The two Cisco SCE 8000s also exchange keep-alive messages and subscriber state information.
In case the primary Cisco SCE 8000 fails, the two Cisco SCE 8000s switch their roles, and this way
switchover is provided.
Figure 3-6
Subscriber
Subscriber
This switchover solution preserves the Cisco SCE 8000 functionality and the network link:
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Cisco SCE8000 GBE Installation and Configuration Guide
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Two Cascaded Cisco SCE 8000 Platforms
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The two Cisco SCE 8000s are simultaneously aware of the subscriber contexts, and subscriber states
are constantly exchanged between them, such that if the primary Cisco SCE 8000 fails, the
secondary can take over with minimum state loss.
When one Cisco SCE 8000 fails (depending on the type of failure) its link traffic is still bypassed to
the functioning Cisco SCE 8000 and processed there, so the traffic processing continues for both the
links.
The bypass of the traffic through the failed Cisco SCE 8000 is configurable, and the user may choose
to always cutoff the line that goes through the failed Cisco SCE 8000. In this case network
redundancy protocols like HSRP are responsible for identifying the line cutoff and switching all the
traffic to go through the functioning Cisco SCE 8000.
In addition, it is possible to configure the Cisco SCE 8000 to use the external optical bypass device
so that if any failure of the Cisco SCE 8000 occurs, it is used to provide link continuity. This ensures
full link continuity at the expense of providing asymmetric routing functionality.
Chapter 3 Cisco SCE 8000 Topology and Topology-Related Parameters
Figure 3-6).
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