Table of Contents
Advertisement
Chapter 10
Redundancy and Fail-Over
•
Failure in the Cascade Connection
The effect of a failure in the cascade connection between the two SCE platforms depends on whether
one or both connections fail:
•
•
Installing a Cascaded System
This section outlines the installation procedures for a redundant solution with two cascaded SCE
platforms.
Refer to the
connections.
Refer to the
When working with two SCE platforms with split-flow and redundancy, it is extremely important to
Note
follow this installation procedure.
Install both SCE platforms, power them up, and perform the initial system configuration.
Step 1
Connect both SCE platforms to the management station.
Step 2
Connect the cascade ports. The cascade ports must be connected directly in Layer 1 (dark fibers), not
Step 3
through a switch. This means that two SCE platforms configured in this mode must look like they are
physically connected, with no switch or router between them.
Set topology configurations for each SCE platform via the connection-mode options. (See
Step 4
Topology-Related Parameters for Redundant Topologies, page
OL-7827-12
Cutoff — Change the link of the failed SCE platform to cutoff (layer 1) forcing the network to
switch all traffic through the line of the working SCE platform. This will, of course, decrease the
network capacity by 50%, but may be useful in some cases.
Effect on the network — The network loses 50% of its capacity (until the failed SCE platform
–
has recovered).
Effect on the SCE platform functionality — The effect on the SCE platform functionality is
–
dependent on the failed SCE platform:
If the failure is in the standby SCE platform — SCE platform continues providing its normal
–
functionality, processing the traffic of its own link.
If the failure is in the active SCE platform — the standby SCE platform takes over processing
–
the traffic, and becomes the active SCE platform. This option is available for use in special
cases, and requires specific configuration.
Only one cascade connection is down — In this case, both SCE platforms can still communicate, so
each still knows the status of the peer.
As long as one cascade connection remains up, the standby will cut off its traffic links so that all
traffic is routed via the active SCE platform. Therefore, split flow is avoided, but at the expense of
half line capacity.
Both cascade links are down — In this case, neither SCE platform knows anything about the status
of the peer. Each platform then works in standalone mode, which means that each SCE platform
processes on its own traffic, only. This results in split flows.
Cisco SCE 2000 Installation and Configuration Guide
Cisco SCE 2000 and SCE 1000 CLI Command Reference
for information on topologies and
10-10)
Cisco SCE 2000 and SCE 1000 Software Configuration Guide
Hot Standby and Fail-over
for details of the CLI commands.
10-7
Advertisement
Table of Contents
