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Configuring ISG Access for IP Subscriber Sessions
Information About ISG Access for IP Subscriber Sessions
5
IP Subscriber Connectivity
IP subscribers connect to ISG through either Layer 2 connected access networks or routed access
networks. The following sections describe these types of IP subscriber connectivity:
•
Layer 2 Connected Access Networks
•
Routed Access Networks
Layer 2 Connected Access Networks
Layer 2 connected subscribers are either directly attached to the physical interfaces of an ISG or
connected to an ISG through a Layer 2 access network, such as a bridged or a switched network. Layer 3
forwarding is either absent or not used to direct subscriber traffic in the Layer 2 access network. IP
addresses of the subscribers may or may not be on the same subnet as the Layer 2 connected physical
interfaces.
Figure 1
shows an example of a Layer 2 connected access network.
Figure 1
Layer 2 Connected Access Network
Routed Access Networks
Routed subscriber traffic is routed through a Layer 3 access network with at least one transit router
before reaching the ISG. IP addresses of the subscribers are at least routable in the Layer 3 access
network. Layer 3 access networks contain a single routing domain and therefore do not support
overlapping IP addresses.
Figure 2
shows an example of a routed access network.
Bridged/switched
access network
Core network
ISG
IP subscriber
IP subscriber
230024
Summary of Contents for IOS XE
Page 14: ...About Cisco IOS XE Software Documentation Additional Resources and Documentation Feedback xii ...
Page 28: ...Using the Command Line Interface in Cisco IOS XE Software Additional Information xiv ...
Page 36: ...Intelligent Services Gateway Features Roadmap 8 ...
Page 46: ...Overview of ISG Feature Information for the Overview of ISG 10 ...
Page 70: ...Configuring ISG Control Policies Feature Information for ISG Control Policies 24 ...
Page 136: ...Configuring MQC Support for IP Sessions Feature Information for MQC Support for IP Sessions 8 ...
Page 224: ...Configuring ISG Subscriber Services Feature Information for ISG Subscriber Services 20 ...
Page 344: ...Service Gateway Interface Feature Information for Service Gateway Interface 8 ...