L2TPv3 IPSEC tunnel or transport mode

[hmc250000]

What is the recommended tunnel mode for L2TPv3 combined with ipsec? No dynamic routing protocols and no gre used. 

Just static routing.

tunnel mode or transport mode? and why?

I've tried both ipsec and transport and both seem to work in my lab but maybe I'm missing something. 

[balaji.bandi]

It all depends on use case where you like to use one on the other.

here is a good document to choose what mode?

http://www.firewall.cx/networking-topics/protocols/870-ipsec-modes.html