L2Tp Lns Support - Cisco ASR 5000 series Product Overview

▀ Features and Functionality - Optional Enhanced Feature Software
L2TP establishes L2TP control tunnels between LAC and LNS before tunneling the subscriber PPP connections as
L2TP sessions. The LAC service is based on the same architecture as the GGSN and benefits from dynamic resource
allocation and distributed message and data processing. This design allows the LAC service to support over 4000 setups
per second or a maximum of over 3G of throughput. There can be a maximum up to 65535 sessions in a single tunnel
and as many as 500,000 L2TP sessions using 32,000 tunnels per system.
The LAC sessions can also be configured to be redundant, thereby mitigating any impact of hardware of software
issues. Tunnel state is preserved by copying the information across processor cards.
Important:
Enhanced Feature Configuration Guide.

L2TP LNS Support

The system configured as a Layer 2 Tunneling Protocol Network Server (LNS) supports the termination secure Virtual
Private Network (VPN) tunnels between from L2TP Access Concentrators (LACs).
The LNS service takes advantage of the high performance PPP processing already supported in the system design and is
a natural evolution from the LAC. The LNS can be used as a standalone, or running alongside a GGSN service in the
same platform, terminating L2TP services in a cost effective and seamless manner.
L2TP establishes L2TP control tunnels between LAC and LNS before tunneling the subscriber PPP connections as
L2TP sessions. There can be a maximum of up to 65535 sessions in a single tunnel and up to 500,000 sessions per LNS.
The LNS architecture is similar to the GGSN and utilizes the concept of a de-multiplexer to intelligently assign new
L2TP sessions across the available software and hardware resources on the platform without operator intervention.
Important:
Enhanced Feature Configuration Guide.
Lawful Intercept
The system supports the Lawful Interception (LI) of subscriber session information. This functionality provides
Telecommunication Service Providers (TSPs) with a mechanism to assist Law Enforcement Agencies (LEAs) in the
monitoring of suspicious individuals (referred to as targets) for potential criminal activity.
The following standards were referenced for the system's LI implementation:
TR-45 Lawfully Authorized Electronic Surveillance TIA/EIA J-STD-025 PN4465 RV 1.7
3GPP TS 33.106 V6.1.0 (2004-06): 3rd Generation Partnership Project; Technical Specification Group Services
and System Aspects; 3G security; Lawful Interception requirements (Release 6)
3GPP TS 33.107 V6.2.0 (2004-06): 3rd Generation Partnership Project; Technical Specification Group Services
and System Aspects; 3G security; Lawful interception architecture and functions (Release 6)
▄ Cisco ASR 5000 Series Product Overview
For more information on this feature support, refer L2TP Access Concentrator chapter in System
For more information on this feature support, refer L2TP Network Server chapter in System
GGSN Support in GPRS/UMTS Wireless Data Services
OL-22938-02