Manual

Layer 2 Tunnel Protocol Version 3
How to Configure Layer 2 Tunnel Protocol Version 3
34
Cisco IOS Releases 12.0(29)S and 12.2(25)S
DETAILED STEPS
Configuring the L2TPv3 Pseudowire
The pseudowire class configuration procedure creates a configuration template for the pseudowire. You
use this template, or class, to configure session-level parameters for L2TPv3 sessions that will be used
to transport attachment circuit traffic over the pseudowire.
The pseudowire configuration specifies the characteristics of the L2TPv3 signaling mechanism,
including the data encapsulation type, the control protocol, sequencing, fragmentation, payload-specific
options, and IP properties. The setting that determines if signaling is used to set up the pseudowire is
also included.
For simple L2TPv3 signaling configurations on most platforms, pseudowire class configuration is
optional. However, specifying a source IP address to configure a loopback interface is highly
recommended. If you do not configure a loopback interface, the router will choose the best available
local address, which could be any IP address configured on a core-facing interface. This configuration
could prevent a control channel from being established. On the Cisco 12000 series Internet routers,
specifying a source IP address is mandatory, and you should configure a loopback interface that is
dedicated for the use of L2TPv3 sessions exclusively. If you do not configure other pseudowire class
configuration commands, the default values are used.
Once you specify the encapsulation l2tpv3 command, you cannot remove it using the no encapsulation
l2tpv3 command. Nor can you change the command's setting using the encapsulation mpls command.
Those methods result in the following error message:
Encapsulation changes are not allowed on an existing pw-class.
Command or Action Purpose
Step 1
enable
Example:
Router> enable
Enables privileged EXEC mode.
• Enter your password if prompted.
Step 2
configure terminal
Example:
Router# configure terminal
Enters global configuration mode.
Step 3
l2tp-class [l2tp-class-name]
Example:
Router(config)# l2tp-class class1
Specifies the L2TP class name and enters L2TP class
configuration mode.
• The l2tp-class-name argument is optional. However, if
you want to configure multiple L2TP classes you must
specify a unique l2tp-class-name for each one.
Step 4
hello interval
Example:
Router(config-l2tp-class)# hello 100
(Optional) Specifies the exchange interval (in seconds) used
between L2TP hello packets.
• Valid values for the interval argument range from 0 to
1000. The default value is 60.