Cisco Systems OL-4387-02 SSG Enhancements for Overlapping Services, Service Translation, 11-7

Chapter 11 Miscellaneous SSG Features

SSG Enhancements for Overlapping Services

SSG Enhancements for Overlapping Services

Overlapping services are services for which the route prefix of one service matches or is contained within the route prefix of another service. For example, the service definition 172.16.253.0/24 overlaps with the service definition 172.16.0.0/16 because the prefix 172.16 is contained in both definitions. The definition 0.0.0.0/0 overlaps all other possible services.

In releases prior to Cisco IOS Release 12.2(16)BX2, the Cisco 10000 router does not allow users to be subscribed to a service if that service overlaps another service to which a different user is subscribed.

To enable service providers to use existing overlapping definitions, the Cisco 10000 router provides the following SSG enhancements:

•Service Translation—Translates overlapping service definitions to a set of non-overlapping service definitions.

•Expansion of Service IDs—Expands the number of service IDs supported from seven to 15. The router uses service IDs to determine which services a user is subscribed to and how to police the user traffic.

For more information, see the following sections:

•Service Translation, page 11-7

•Expansion of Service IDs, page 11-11

Service Translation

The service translation mechanism translates overlapping service definitions to a set of non-overlapping service definitions that are used internally to the router. Instead of using the service definitions that the Cisco Subscriber Edge Services Manager (SESM) downloads, the router uses the translated network sets to provide the desired behavior. A network set can contain a single unique prefix or multiple unique prefixes.

To further clarify service translation for the Cisco 10000 router, consider the following example in which services that are defined in SESM are converted to sets (for example, service networks). The

Cisco 10000 router uses these sets internally to provide the desired behavior. The following services are defined in the example:

ssg bind service Default_256 <next hop ssg> 0.0.0.0/0.0.0.0

ssg bind service Bronze_256 <next hop ssg> 10.58.253.0/255.255.255.0 10.58.254.0/255.255.255.0

ssg bind service Silver_512 <next hop ssg> 10.58.253.0/255.255.255.0 10.58.254.0/255.255.255.0 10.58.102.6/255.255.255.255

ssg bind service Gold_2048 <next hop ssg> 10.58.253.0/255.255.255.0 10.58.254.0/255.255.255.0 10.58.102.6/255.255.255.255

ssg bind service Platinum_1024 <next hop ssg> 10.58.253.0/255.255.255.0

Cisco 10000 Series Router Service Selection Gateway Configuration Guide

OL-4387-02 11-7