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Chapter 3 Cisco SCE8000 Topology and Topology-Related Parameters
Physical Topologies
• The two Cisco SCE8000s are simultaneously aware of the subscriber contexts, and subsc riber states
are constantly exchanged between them, such that if the primary Cisco SCE8000 fails, the secondary
can take over with minimum state loss.
• When one Cisco SCE8000 fails (depending on the type of failure) its link traffic is still bypassed to
the functioning Cisco SCE8000 and processed there, so the traffic processing continues for both the
links.
• The bypass of the traffic through the failed Cisco SCE8000 is configurable, and the user may choose
to always cutoff the line that goes through the failed Cisco SCE8000. 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 SCE8000.
• In addition, it is possible to configure the Cisco SCE8000 to use the external optical bypass device
so that in the event of any failure of the Cisco SCE8000, it will be used to provide link continuity.
This ensures 100% link continuity at the expense of providing asymmetric routing functionality.
Multi-Gigabit Service Control Platform (MGSCP) Topology
In this topology, multiple Cisco SCE8000 platforms are connected to a Cisco 7600 Series router, which
acts as a dispatcher between the platforms. The r outer contains two EtherChannels (ECs), one for the
subscriber side and one for the network side, that perform load balancing for the SCE platform traffic.
Traffic enters the first router, is distributed between the SCE platforms by the subscriber-side EC and
then returns to the router so it can be forwarded to its original destination.
Figure 3-7 Basic MGSCP Topology
There are a number of variables to be considered in the MGSCP topology. Two of the main factors to be
considered include:
• Type of SCE Platform Redundancy, page 3-8
• Redundant Cisco 7600 Series Router, page 3-8
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SCE8000s
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Cisco 7600 40Gig
Subscribers
Internet