Manual

Layer 2 Tunnel Protocol Version 3
How to Configure Layer 2 Tunnel Protocol Version 3
27
Cisco IOS Releases 12.0(29)S and 12.2(25)S
Configuring L2TPv3 Control Channel Authentication Parameters
Two methods of control channel authentication are available in Cisco IOS Release 12.0(29)S. The
L2TPv3 Control Channel Hashing feature introduces a more robust authentication method than the older
CHAP-style L2TP control channel method of authentication. You may choose to enable both methods
of authentication to ensure interoperability with peers that support only one of these methods of
authentication, but this configuration will yield control of which authentication method is used to the
peer PE router. Enabling both methods of authentication should be considered an interim solution to
solve backward-compatibility issues during software upgrades.
The principal difference between the L2TPv3 Control Connection Authentication feature and
CHAP-style L2TP control channel authentication is that, instead of computing the hash over selected
contents of a received control message, the L2TPv3 Control Connection Authentication feature uses the
entire message in the hash. In addition, instead of including the hash digest in only the SCCRP and
SCCCN messages, it includes it in all L2TP messages.
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
receive-window size
Example:
Router(config-l2tp-class)# receive-window 30
(Optional) Configures the number of packets that can be
received by the remote peer before backoff queueing occurs.
• The valid values range from 1 to the upper limit the peer
has for receiving packets. The default value is the upper
limit.
Step 5
retransmit {initial retries initial-retries |
retries retries | timeout {max | min} timeout}
Example:
Router(config-l2tp-class)# retransmit retries
10
(Optional) Configures parameters that affect the
retransmission of control packets.
• initial retries—specifies how many SCCRQs are
re-sent before giving up on the session. Valid values for
the initial-retries argument range from 1 to 1000. The
default value is 2.
• retries—specifies how many retransmission cycles
occur before determining that the peer PE router does
not respond. Valid values for the retries argument range
from 1 to 1000. The default value is 15.
• timeout {max | min}—specifies maximum and
minimum retransmission intervals (in seconds) for
resending control packets. Valid values for the timeout
argument range from 1 to 8. The default maximum
interval is 8; the default minimum interval is 1.
Step 6
timeout setup seconds
Example:
Router(config-l2tp-class)# timeout setup 400
(Optional) Configures the amount of time, in seconds,
allowed to set up a control channel.
• Valid values for the seconds argument range from 60 to
6000. The default value is 300.
Command or Action Purpose