PDN Gateway Overview
▀ Features and Functionality - Optional Enhanced Feature Software
▄ Cisco ASR 5x00 Packet Data Network Gateway Administration Guide
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A connected-active subscriber session would be in “ECM Connected state,” as specified in 3GPP TS 23.401, with a data
packet sent/received within the last one minute (on average). This transactional model allows providers to better manage
and achieve more predictable spending on their capacity as a function of the Total Cost of Ownership (TCO).
Common Gateway Access Support
Common Gateway Access support is a consolidated solution that combines 3G and 4G access technologies in a common
gateway supporting logical services of HA, P-GW, and GGSN to allow users to have the same user experience,
independent of the access technology available.
In today’s scenario, an operator must have multiple access networks (CDMA, eHRPD, and LTE) plus a GSM/UMTS
solution for international roaming. Therefore, operators require a solution to allow customers to access services with the
same IP addressing behavior and to use a common set of egress interfaces, regardless of the access technology (3G or
4G).
This solution allows static customers to access their network services with the same IP addressing space assigned for
wireless data, regardless of the type of connection (CDMA, eHRPD/LTE, or GSM/UMTS). Subscribers using static IP
addressing will be able to get the same IP address regardless of the access technology.
Dynamic RADIUS Extensions (Change of Authorization)
Use of Dynamic RADIUS Extensions (CoA and PoD) requires that a valid license key be installed. Contact your Cisco
account representative for information on how to obtain a license.
Dynamic RADIUS extension support provide operators with greater control over subscriber PDP contexts by providing
the ability to dynamically redirect data traffic, and or disconnect the PDP context.
This functionality is based on the RFC 3576, Dynamic Authorization Extensions to Remote Authentication Dial In User
Service (RADIUS), July 2003 standard.
The system supports the configuration and use of the following dynamic RADIUS extensions:
Change of Authorization
: The system supports CoA messages from the AAA server to change data filters
associated with a subscriber session. The CoA request message from the AAA server must contain attributes to
identify NAS and the subscriber session and a data filter ID for the data filter to apply to the subscriber session.
Disconnect Message
: The DM message is used to disconnect subscriber sessions in the system from a RADIUS
server. The DM request message should contain necessary attributes to identify the subscriber session.
The above extensions can be used to dynamically re-direct subscriber PDP contexts to an alternate address for
performing functions such as provisioning and/or account set up. This functionality is referred to as Session Redirection,
or Hotlining.
Session redirection provides a means to redirect subscriber traffic to an external server by applying ACL rules to the
traffic of an existing or a new subscriber session. The destination address and optionally the destination port of TCP/IP
or UDP/IP packets from the subscriber are rewritten so the packet is forwarded to the designated redirected address.
Return traffic to the subscriber has the source address and port rewritten to the original values. The redirect ACL may be
applied dynamically by means of the Radius Change of Authorization (CoA) extension.
Important:
For more information on dynamic RADIUS extensions support, refer to the
CoA, RADIUS, And
Session Redirection (Hotlining)
appendix in this guide.
