Cisco SFE2000P User Manual

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Cisco SCE 2000 4xGBE Installation and Configuration Guide
OL-7824-06
Chapter 3 Information About Topology
Information About Topology Considerations
Asymmetric Routing Topology
In some Service Control deployments, asymmetrical routing occurs between potential service control
insertion points. Asymmetrical routing can cause a situation in which the two directions of a
bi-directional flow pass through different SCE platforms, resulting in each SCE platform seeing only one
direction of the flow (either the inbound traffic or the outbound traffic).
This problem is typically solved by connecting the two SCE platforms in cascade mode (or through an
MGSCP cluster), thereby making sure that both directions of a flow run through the same SCE platform.
However, this is sometimes not feasible, due to the fact that the SCE platforms sharing the split flow are
geographically remote (especially common upon peering insertion). In this type of scenario, the
asymmetric routing solution enables the SCE platform to handle such traffic, allowing SCA BB to
classify traffic based on a single direction and to apply basic reporting and global control features to
uni-directional traffic.
Asymmetric Routing and Other Service Control Capabilities
Asymmetric routing can be combined with most other Service Control capabilities, however there are
some exceptions.
Service Control capabilities that cannot be used in an asymmetric routing topology include the
following:
• Subscriber redirect
• Subscriber notification
• Any kind of subscriber integration, including MPLS VPN. (Use subscriber-less mode or anonymous
subscriber mode instead)
• Classical open flow mode , including the following:
– Flow-open-mode classical explicitly enabled (ROOT level configuration)
– VAS traffic forwarding mode enabled
– Analysis layer transport mode enabled (ROOT level configuration)
– ‘no TCP bypass-establishment’ mode enabled (ROOT level configuration)
– A traffic rule is configured for certain flows to use the classical open flow mode (ROOT level
configuration)
Information About Physical Topologies
Following are descriptions of a number of physical topologies that the SCE 2000 supports.
• Information About Inline SCE 2000 Topologies
• Single Link: Receive-only Topology
• Dual Link: Receive-Only Topology
Information About Inline SCE 2000 Topologies
A single SCE 2000 supports both single GBE link and dual GBE link topologies.
• Single Link: Inline Topology
• Dual link: Inline Installation

Cisco SFE2000P Specifications

General

Brand	Cisco
Model	SFE2000P
Category	Network Router
Language	English