NLB and Directed Broadcast consume resources from the same pool of 200 resources. When you configure either NLB or Directed Broadcast, the switch uses one resource. If you configure both NLB and Directed Broadcast, the switch uses two resources.
To avoid a situation where there is a lack of resources, adhere to the following limits:
The number of NLB cluster IP interfaces multiplied by the number of configured clusters must be equal to, or less than, 200. The number of NLB cluster IP interfaces is the key, not the number of VLANs. You can configure 1 VLAN with up to 200 NLB cluster IP interfaces or configure up to 200 VLANs with 1 NLB cluster IP interface per VLAN.
For example: 1 NLB cluster IP interface x 200 clusters = 200 or 2 NLB cluster IP interfaces x 100 clusters = 200
If you configure VLANs with Directed Broadcast only, you can scale up to 200 VLANs.
If you configure VLANs with both NLB and Directed Broadcast, you can only scale up to 100 VLANs assuming there is only 1 NLB cluster IP interface per VLAN.
For information on Directed Broadcast, see Denial-of-Service Attack Prevention.