View HA External and Internal

I need to setup HA for my View 5.1 environment. From doing some research it looks like I need to setup 2 security servers and 2 connection servers and configure both sets with NLB. Is this correct?

                                 security server 1 --- connection server 1
                                /                                           |
external nlb cluster ip/fqdn                    internal nlb cluster ip/fqnd
                                \                                           |                                             
                                 security server 2 --- connection server 2

Thanks,

Mike