Question about the MTU in DMVPN

[rookie R]

Hi!

Can anyone please tell me what is the MTU when using DMVPN (mGRE and NHRP + IPSEC, ESP with tunnel mode)? When I use the command "ip mtu XXXX" to configure interface tunnel 0, what does this MTU contain? Does MTU include all the fields in this image? How to configure the appropriate MTU value?

[MHM Cisco World]

Fragmentation Needed: Path MTU Discovery with DMVPN Tunnels

check this link

[pman]

Hi,

Try to read example 9 and 10 in the following link:

https://www.cisco.com/c/en/us/support/docs/ip/generic-routing-encapsulation-gre/25885-pmtud-ipfrag.html#anc25

and then read the "More Recommendations".