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Cisco SD-WAN
Product Documentation
Viptela Documentation


vpn interface pmtu—Enable path MTU (PMTU) discovery on the interface, using ICMP. When PMTU is enabled, the device automatically negotiates the largest MTU size that the interface supports in an attempt to minimize or eliminate packet fragmentation.

By default, PMTU discovery using ICMP is disabled.

On vEdge routers, the Viptela BFD software automatically performs PMTU discovery on each transport connection (that is, for each TLOC, or color). BFD PMTU discovery is enabled by default, and it is recommended that you use it and that you not configure ICMP PMTU discovery on router interfaces.

vManage Feature Template

Configuration ► Templates ► VPN Interface Cellular (for vEdge cellular wireless routers only)
Configuration ► Templates ► VPN Interface Ethernet
Configuration ► Templates ► VPN Interface PPP Ethernet

Command Hierarchy

vpn vpn-id
  interface interface-name



Operational Commands

show interface detail


Enable path MTU discovery on a vSmart interface:

vpn 0
​  interface eth1

Release Information

Command introduced in Viptela Software Release 14.1.​

Additional Information

See the Configuring Interfaces article for your software release.
bfd color pmtu-discovery

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