Cisco Cisco IOS Software Release 12.0(23)S

This configuration procedure binds an Ethernet, 802.1q VLAN, or Frame Relay attachment circuit to an 
L2TPv3 pseudowire for Xconnect service. The virtual circuit identifier that you configure creates the 
binding between a pseudowire configured on a PE router and an attachment circuit in a CE device. The 
virtual circuit identifier configured on the PE router at one end of the L2TPv3 control channel must also 
be configured on the peer PE router at the other end. 

Router(config-pw)# ip pmtu

(Optional) Enables the discovery of the path maximum 
transmission unit (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.

The ip pmtu command is not supported if you disabled 
signaling with the protocol none command in 

Step 3

.

Router(config-pw)# ip tos {value value | 

}

(Optional) Configures the value of the ToS byte in IP headers of 
tunneled packets, or reflects the ToS byte value from the inner IP 
header. Valid values for the value argument range from 0 to 255. 
The default ToS byte value is 0.

Router(config-pw)# ip dfbit set

(Optional) Configures the value of the DF bit in the outer headers 
of tunneled packets. Use this command if (for performance 
reasons) you do not want reassembly of tunneled packets to be 
performed on the peer PE router. This command is disabled by 
default.

Router(config-pw)# ip ttl value

(Optional) Configures the value of the time to live (TTL) byte in 
the IP headers of tunneled packets. Valid values for the value 
argument range from 1 to 255. The default TTL byte value is 255.

Router(config-pw)# ip protocol {l2tp | 

 | protocol-number}

(Optional) Configures the IP protocol to be used for tunneling 
packets. For backward compatibility with UTI, enter uti or 120, 
the UTI protocol number. The default IP protocol value is l2tp or 
115, the L2TP protocol number. 

Router(config-pw)# sequencing {transmit | 

 | both}

(Optional) Specifies the direction in which sequencing of data 
packets in a pseudowire is enabled:

transmit—Updates the Sequence Number field in the 
headers of data packets sent over the pseudowire according to 
the data encapsulation method that is used.

receive—Keeps the Sequence Number field in the headers of 
data packets received over the pseudowire. Out-of-order 
packets are dropped.

both—Enables both the transmit and receive options.