L2TP Access Concentrator
Supported LAC Service Configurations for PDSN Simple IP ▀
Cisco ASR 5x00 Packet Data Network Gateway Administration Guide ▄
387
Important:
These instructions assume that the system was previously configured to support subscriber data
sessions as a PDSN.
Step 1
Configure the subscriber profiles according to the information and instructions located in the
Configuring Subscriber
Profiles for L2TP Support
section of this chapter.
Step 2
Configure one or more LAC services according to the information and instructions located in the
Configuring LAC
Services
section of this chapter.
Step 3
Configure the PDSN service(s) with the tunnel context location according to the instructions located in the
Modifying
PDSN Services for L2TP Support
section of this chapter.
Step 4
Save your configuration to flash memory, an external memory device, and/or a network location using the Exec mode
command
save configuration
. For additional information on how to verify and save configuration files, refer to the
System Administration Guide
and the
Command Line Interface Reference
.
PDSN Service-based Compulsory Tunneling
This section describes the working of service-based compulsory tunneling and its configuration.
How PDSN Service-based Compulsory Tunneling Works
PDSN Service-based compulsory tunneling enables wireless operators to send all PPP traffic to remote LNS peers over
an L2TP tunnel for authentication. This means that no PPP authentication is performed by the system.
Accounting start and interim accounting records are still sent to the local RADIUS server configured in the system’s
AAA Service configuration. When the L2TP session setup is complete, the system starts its call counters and signals the
RADIUS server to begin accounting. The subscriber name for accounting records is based on the NAI-constructed name
created for each session.
PDSN service-based compulsory tunneling requires the modification of one or more PDSN services and the
configuration of one or more LAC services.
The following figure and the text that follows describe how PDSN service-based compulsory tunneling is performed
using the system.