The ASR 1000 Series Routers can be deployed as an IP session aggregator. The maximum number of IP sessions that can be supported depends on the hardware combination.

Table below lists the iWAG scaling numbers and maximum number of IP sessions supported on the ASR 1000 hardware:

• Hardware combination and the maximum number of IP sessions that are supported when used for SP WiFi applications.

The session limits apply to all variety of IP session initiators: DHCP, unclassified Mac address, unclassified IP, and radius proxy.

• Hardware combinations for SP WiFi applications and the corresponding Simple IP use case scale numbers for authenticated and walk-by users.

Note	Other hardware variants are not supported for SP WiFi applications. For more information, see Restrictions for iWAG Scalability, page 3

The scale numbers provided in the table below assumes the following reference configuration:

• Walk-by users: A maximum of three traffic classes on the default session.
• Authenticated users: There are no traffic classes for authenticated users.

Any deviation from the conditions mentioned above may result in different scale numbers. The scale limits and the hardware combinations listed in the next table requires 16GB of DRAM on ASR1000 Route Processor 2 (RP2).

The following are the restrictions pertaining to iWAG scalability:

The Intelligent Wireless Access Gateway (iWAG) feature is not supported on the following hardware.

• RP1 with ESP10 or ESP20
• ASR1002
• ASR1002F

The ASR 1000 supports the ability to redirect IP traffic within an ISG traffic class. Layer 4 redirect scaling is performed by the Quantum Flow Processor (QFP). The scaling limits are dependent on the ESP.

The Call Admission Control (CAC) feature is configured to protect the ASR 1000 processing resources that must be configured. CAC can restrict creation of new sessions when system resources exceed configured thresholds.

For examples about configuring the CAC for IPoE feature, see the “Call Admission Control” section in the Intelligent Wireless Access Gateway Configuration Guide located at:

http:/​/​www.cisco.com/​en/​US/​docs/​routers/​asr1000/​configuration/​guide/​chassis/​IWAG_​Config_​Guide_​BookMap_​chapter_​01001.html

In public wireless LAN (PWLAN) setups, a high number of ISG sessions might be unauthenticated sessions from wireless devices that do not use the PWLAN service. These sessions are referred to in this document as walk-by sessions, and users that use these sessions are referred to as walk-by users.

Walk-by sessions, if not dealt with in an optimized way, may consume a large portion of the hardware resources. This resource utilization may lead to an increase in the number of ISG routers required for a given PWLAN deployment. The concept of light-weight sessions is introduced to provide an optimization for walk-by sessions.

The features for walk-by users are configured on a default session acting as a template. Walk-by users are then assigned light-weight sessions that inherit features from a default session. The features are configured only once on the default session, thereby optimizing the resource usage.

A lite session is a light-weight unauthenticated ISG session that inherits default session services. Lite sessions are created on ISG to support walk-by users and optimize resource usage. A timer may be specified to limit the duration for which the lite session can utilize the public wireless LAN (PWLAN) services while remaining unauthenticated.

On the ASR 1000 Series router, the Layer 4 Redirect (L4R) feature supports a maximum of 16 translation entries per walk-by session. For more information on the limit for the total number of translations on the system, see Layer 4 Redirect Scaling.

For platform-independent restrictions pertaining to the walk-by sessions and information on how to configure the Walk-By User Support for PWLAN in ISG feature, refer to the following URL: http:/​/​www.cisco.com/​en/​US/​docs/​ios-xml/​ios/​isg/​configuration/​xe-3s/​isg-wlkby-supp.html