Cisco Systems SCE 2000 4xGBE Network Router User Manual


 
Chapter 3 Topology
Topology Considerations
SCE 2000 4xGBE Installation and Configuration Guide
3-2 OL-7824-02
Number of links: The SCE 2000 may be connected to one or two GBE links. This is relevant
for both bump-in-the-wire and Receive-Only topologies.
Redundancy: Must the system be designed to guarantee uninterrupted SCE 2000
functionality? If so, there must be a backup SCE 2000 Platform to assume operation in case of
failure of the primary device.
Link continuity: How should the SCE 2000 respond to platform failure with regard to link
continuity? Should traffic flow continue even though the unit is not operating, or be halted
until the platform is repaired/replaced?
These issues determine three important aspects of system deployment and configuration:
How many SCE 2000 Platforms are needed and how will they be installed?
Physical topology of the system: The actual physical placement of the SCE 2000 in the
system.
Topology-related configuration parameters: The correct values for each parameter must be
ascertained before configuring the system to make sure that the system will function in the
desired manner.
Functionality
The SCE 2000 can serve one of two general functions:
Monitoring and Control: The SCE 2000 monitors and controls traffic flow. Decisions are
enforced by the SCE 2000 depending on the results of the monitoring functions of the SCE
2000 and the configuration of the Service Control Application for Broadband or Mobile
solution.
In order to perform control functions, the SCE 2000 must be physically installed as a bump-
in-the-wire, and the connection mode must be “Inline”.
Monitoring only: The SCE 2000 monitors traffic flow, but cannot control it.
Either a bump-in-the-wire installation or an optical splitter installation may be used for
monitoring only. In the latter case connection mode must be “receive-only”.
Number of links
The SCE 2000 can be deployed in a single GBE link or in two GBE links. The two-link topology
may implement load-sharing and the SCE 2000 in this case is able to process both directions of a
bi-directional flow even if they split to both links.
Redundancy
When a high degree of reliability is desired, a second SCE 2000 Platform should be installed to
provide backup operation capabilities. The combination of two SCE 2000s guarantees
uninterrupted functioning in case of a failure of one of the platforms. The two SCE 2000s are
cascaded, so that, although all processing is performed only in the active SCE 2000, the standby
SCE 2000 is constantly updated with all the necessary information so that it can instantly take
over processing the traffic on the data links should the active SCE 2000 fail.
If only preservation of the network links is required, and uninterrupted functionality of the SCE
2000 is not required, a single SCE 2000 is sufficient.