Wrong statement about CPU utilization if Neutron with GRE segmentation is used.

[Pavel Vaylov]

Team, there is a wrong statement in documentation about CPU utilization if Neutron with GRE segmentation is used:

http://docs.mirantis.com/openstack/fuel/fuel-5.0/pre-install-guide.html

… But GRE encapsulation decreases the speed of communication between the VMs and decreases the CPU utilization of the Compute and Controller nodes. So, if you do not need really fast interconnections between VMs, do not want to predetermine the maximum number of tenants, and do not want to configure your network equipment, you can choose the Neutron + GRE topology. ..

Really GRE segmentation increases CPU utilization on nodes.

Impact: Customers may think that it better to use GRE segmentation instead of VLAN on production environment. It should clear that GRE segmentation decreases network performance an increases CPU utilization.

[Evgeny Kozhemyakin (ekozhemyakin)]

Opps. It's been already corrected in master.

[Pavel Vaylov (pvaylov)]

Team, we also should update our current manual.