Cisco Cisco ASR 5000
LNS Service Configuration Mode Commands
single-port-mode ▀
Command Line Interface Reference, StarOS Release 18 ▄
7013
single-port-mode
When enabled, this command sets the LNS to use only the default local UDP port (port 1701) for the life of a tunnel.
Product
PDSN
GGSN
Privilege
Security Administrator, Administrator
Mode
Exec > Global Configuration > Context Configuration > LNS Service Configuration
configure > context context_name > lns-service service_name
Entering the above command sequence results in the following prompt:
[context_name]host_name(config-lns-service)#
Syntax
[ default | no ] single-port-mode
no
Disable single port mode
Usage
Use this command to control the L2TP LNS tunnel local UDP port assignment mode. If single-port-mode is
enabled, the LNS-service uses the standard UDP port (port 1701) for the life of the incoming tunnel.
Otherwise, it assigns a new local UDP port number for a tunnel when it responds to a tunnel create request
received on the standard port number. This is done for load distributing the tunnel processing between
multiple tasks within the system to increase the capacity and performance. Even though all L2TP LACs are
required to support such dynamic port assignments during tunnel establishments, there exist some LACs that
do not support port assignment other than port 1701. This single-port-mode feature can be enabled to support
such LAC peers. This configuration must be applied for the LNS-Service before the
enabled, the LNS-service uses the standard UDP port (port 1701) for the life of the incoming tunnel.
Otherwise, it assigns a new local UDP port number for a tunnel when it responds to a tunnel create request
received on the standard port number. This is done for load distributing the tunnel processing between
multiple tasks within the system to increase the capacity and performance. Even though all L2TP LACs are
required to support such dynamic port assignments during tunnel establishments, there exist some LACs that
do not support port assignment other than port 1701. This single-port-mode feature can be enabled to support
such LAC peers. This configuration must be applied for the LNS-Service before the
bind
command is
executed.
Example
The following command enables single port mode for the current LNS service:
single-port-mode