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How to configure the concurrent session limit on the Cisco VPN 3000 Concentrator



This document decribes how to configure session limit on the CISCO VPN 3000 Concentrator.


What VPN concentrator do?

Generally, VPN concentrtor is used for providing Remote Access VPN. Through Remote Access VPN users are permitted to use an encrypted tunnel to securely access other network via internet.Recently, VPNC is also used for the encrytion of WLAN or wired traffic, especially for specific users in scenarios  where there is a worry with respect to the consequences if login/password are captured. Remote Access VPN along  with the WLAN are widely used for a short span where administrators don't want to go through the tedious processes of installing drivers and OS support issues, WPA, 802.11i, etc.Remote Access VPN connectivity through either IPsec or SSL for the VPN can be achieved by using the Cisco VPN  Concentrator 3000 series.By using RADIUS, Kerberos or MS Active Directory, RSA SDI, digital certificates, or the built-in authentication server user authentication can be done.


Navigate to Configuration > System > General > Sessions to configure the concurrent session limit.


The Cisco VPN 3000 Concentrator supports IPSec, Point-to-Point Tunneling Protocol (PPTP), L2TP/IPSec, and WebVPN sessions, either singly or in combination.

The Sessions Screen provides a means to limit the number of simultaneous active sessions to fewer sessions than the VPN concentrator can potentially support. For session limits, the VPN concentrator treats IPSec, PPTP, and L2TP/IPSec sessions together; the Maximum Active Sessions parameter applies to all of them, and the Maximum Active WebVPN Sessions parameter applies to WebVPN sessions.

While it seems intuitive that if the maximum number of one type of session is lowered, the VPN concentrator could support more of the other, that is not how the VPN Concentrator works. If the the number of active sessions of either type is artificially lowered, this in fact lowers the capacity of the VPN concentrator to support both types of sessions.

The VPN concentrator hardware determines the maximum number of sessions supported, which depends on the model used.

For a further explanation session support on different VPN 3000 concentrator models, refer to the Maximum Sessions section of Release Notes for Cisco VPN 3000 Series Concentrator, Release 4.1.7.E.


Problem Type

How to (General Information)


Product Family

VPN - 3000 series concentrator


VPN Protocols