One of the advantages of using UAG for DirectAccess is that you can create high-availability arrays, and use NLB to make sure that even if several members of the array go down, there’s always going to be connectivity as long as a single member remains (although performance will suffer).
UAG DirectAccess arrays support two kinds of load balancing:
- Native load balancing with Windows NLB
- External load balancing with “hardware” load balancer
In a typical deployment, you will need an internal and external load balancer. You can see an example of that at http://technet.microsoft.com/en-us/library/ee690463.aspx
However, when you have a IPv4 only network behind the UAG DA array, you can get rid of the internal load balancer. How? Check out the UAG Team blog post on this subject to find the answer:
DEBRA LITTLEJOHN SHINDER
MVP (Enterprise Security)