Open vSwitch GRE tunneling support

modulename: vport-gre.ko

configname: CONFIG_OPENVSWITCH_GRE

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>Open vSwitch GRE tunneling support
In linux kernel since version 3.11 (release Date: 2013-09-02)  
If you say Y here, then the Open vSwitch will be able create GRE
vport.

Say N to exclude this support and reduce the binary size.

If unsure, say Y.

source code: