Manual

Layer 2 Tunnel Protocol Version 3
How to Configure Layer 2 Tunnel Protocol Version 3
36
Cisco IOS Releases 12.0(29)S and 12.2(25)S
Step 5
protocol {l2tpv3 | none}[l2tp-class-name]
Example:
Router(config-pw)# protocol l2tpv3 class1
(Optional) Specifies the L2TPv3 signaling protocol to be
used to manage the pseudowires created with the control
channel parameters in the specified L2TP class (see the
section “Configuring L2TP Control Channel Parameters”).
• If the l2tp-class-name argument is not specified, the
default values for L2TP control channel parameters
will be used. The default protocol option is l2tpv3.
• If you do not want to use signaling in the L2TPv3
sessions created with this pseudowire class, enter
protocol none. (The protocol none configuration is
necessary when configuring interoperability with a
remote peer that runs UTI.)
Step 6
ip local interface interface-name
Example:
Router(config-pw)# ip local interface e0/0
Specifies the PE router interface whose IP address is to be
used as the source IP address for sending tunneled packets.
• Use the same local interface name for all pseudowire
classes configured between a pair of PE routers.
Note This command must be configured for
pseudowire-class configurations using L2TPv3 as
the data encapsulation method.
Step 7
ip pmtu
Example:
Router(config-pw)# ip pmtu
(Optional) Enables the discovery of the path MTU for
tunneled traffic.
• This command enables the processing of ICMP
unreachable messages that indicate fragmentation
errors in the backbone network that carries L2TPv3
session traffic. Also, this command enables MTU
checking for IP packets sent into the session and that
have the DF bit set. Any IP packet larger than the MTU
is dropped and an ICMP unreachable message is sent.
MTU discovery is disabled by default.
Note The ip pmtu command is not supported if you
disabled signaling with the protocol none
command in Step 5.
• This command must be enabled in the pseudowire class
configuration for fragmentation of IP packets before
the data enters the pseudowire to occur.
Note For fragmentation of IP packets before the data
enters the pseudowire, it is recommended that the ip
dfbit set command is also enabled in the
pseudowire class configuration. This allows the
PMTU to be obtained more rapidly.
Command or Action Purpose