Table of Contents
Advertisement
Information About Redundancy and Fail-Over
Terminology and Definitions
Following is a list of definitions of terms used in the chapter as they apply to the Cisco fail-over solution,
which is based on cascaded SCE platforms.
•
•
•
•
Redundant Topologies
All Cisco SCE platforms include an internal electrical bypass module, which provide the capability of
preserving the network link in case the SCE platform fails. The SCE platform, which can handle two
data links, includes two such bypass modules. However, in some cases, the service provider wishes to
preserve the SCE platform functionality in case of a failure, in addition to preserving the network link.
Cisco provides a unique solution for this scenario, through deploying two cascaded SCE platforms on
these two data links.
The cascading is implemented by connecting the two SCE platforms using two of the data links. This
fail over solution applies to both inline and receive-only topologies.
In each SCE platform, two of the four data interfaces are connected to each of the network links, while
the other two data interfaces are used for cascading between the SCE platforms. (See the Cisco SCE 2000
Installation and Configuration Guide for specific cabling procedures for redundant topologies.) The
cascade ports are used for transferring network traffic, keep-alive messages and subscriber state updates.
Cisco SCE 2000 and SCE 1000 Software Configuration Guide
10-2
Fail-over — A situation in which the SCE platform experiences a problem that makes it impossible
for it to provide its normal functionality, and a second SCE platform device immediately takes over
for the failed SCE platform.
Hot standby — When two SCE platforms are deployed in a fail over topology, one SCE platform is
active, while the second SCE platform is in standby, receiving from the active SCE platform all
subscriber state updates and keep alive messages.
Primary/Secondary — The terms Primary and Secondary refer to the default status of a particular
SCE platform. The Primary SCE Platform is active by default, while the Secondary device is the
default standby. Note that these defaults apply only when both devices are started together. However,
if the primary SCE platform fails and then recovers, it will not revert to active status, but remains in
standby status, while the secondary device remains active.
Subscriber state fail-over — A fail over solution in which subscriber state is saved.
Chapter 10
Redundancy and Fail-Over
OL-7827-12
Advertisement
Table of Contents
