Pdp Context Support - Cisco ASR 5000 Series Administration Manual

▀ Features and Functionality - Base Software
The system supports two type of overlapping pools: resource and overlap. Resource pools are designed for dynamic
assignment only, and use a VPN tunnel, such as a GRE tunnel, to forward and received the private IP addresses to and
from the VPN. Overlapping type pools can be used for both dynamic and static, and use VLANs and a next hop
forwarding address to connect to the VPN customer.
To forward downstream traffic to the correct PDP context, the GGSN uses either the GRE tunnel ID, or the VLAN ID to
match the packet. When forwarding traffic upstream, the GGSN uses the tunnel and forwarding information in the IP
pool configuration, so overlapping pools must be configured in the APN for this feature to be used.
When a PDP context is created, the IP addresses is either assigned from the IP pool, in this case the forwarding rules are
also configured into the GGSN at this point. If the address is assigned statically, when the GGSN confirms the IP
address from the pool configured in the APN, the forwarding rules are also applied.
The GGSN can scale to as many actual overlapping pools as there are VLAN interfaces per context, and there can be
multiple contexts per GGSN, or when using resource then the limit is the number of IP pools. This scalability allows
operators, who wish to provide VPN services to customers using the customer's private IP address space, need not be
concerned about escalating hardware costs, or complex configurations.
Important:
Enhanced Feature Configuration Guide.

PDP Context Support

Support for subscriber primary and secondary Packet Data Protocol (PDP) contexts in accordance with the following
standards:
3GPP TS 23.060 v7.4.0 (2007-9): 3rd Generation Partnership project; Technical Specification Group Services
and System Aspects; General Packet Radio Service (GPRS); Service description (Release 1999) as an
additional reference for GPRS/UMTS procedures
3GPP TS 29.061 v7.6.0 (2008-09): 3rd Generation Partnership Project; Technical Specification Group Core
Network; Packet Domain; Interworking between the Public Land Mobile Network (PLMN) supporting Packet
Based Services and Packet Data Networks (PDN) (Release 4)
PDP context processing is based on the APN that the subscriber is attempting to access. Templates for all of the possible
APNs that subscribers will be accessing must be configured within the system. Up to 1024 APNs can be configured on
the system.
Each APN template consists of parameters pertaining to how PDP contexts are processed such as the following:
Type (IPv4, IPv6, and/or PPP)
Accounting protocol (GTPP or RADIUS
Authentication protocol (CHAP, MSCHAP, PAP, MSID-based)
Charging characteristics (use SGSN-supplied or use configured)
IP address allocation method (static or dynamic)
PDP Context timers
▄ Cisco ASR 5000 Series Gateway GPRS Support Node Administration Guide
For more information on IP pool overlapping configuration, refer VLANs chapter in System
GGSN Support in GPRS/UMTS Wireless Data Services
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