HOTSPOT
Your network contains an Active Directory domain named contoso.com. The domain
contains two member servers named Server1 and Server2. All servers run Windows Server
2012 R2.
Server1 and Server2 have the Network Load Balancing (NLB) feature installed. The servers
are configured as nodes in an NLB cluster named Cluster1. Both servers connect to the
same switch.
Cluster1 hosts a secure web Application named WebApp1. WebApp1 saves user state
information in a central database.
You need to ensure that the connections to WebApp1 are distributed evenly between the
nodes. The solution must minimize port flooding.
What should you configure? To answer, configure the appropriate affinity and the
appropriate mode for Cluster1 in the answer area.
Answer: 
Explanation:
http://technet.microsoft.com/en-us/library/cc782694(v=ws.10).aspx
Affinity – Single
Mode – Multicast
Passleader suggest “Affinity = Class C” however I would choose “Affinity = Single” as well. What’s the Point with the “port-flooding” part within the question?
To answer my own question: I gues to minimize “port-flooding” one should choose the “multicast-mode” over the “Unicast-mode”. I think the term “port-flooding” is misleading in that respect. Rephrasing it to “minimize traffic” would make it more clear.
It’s single and multicast.
Unicast – Each NLB cluster node replaces its real (hard coded) MAC address with a new one (generated by the NLB software) and each node in the NLB cluster uses the same (virtual) MAC. Because of this virtual MAC being used by multiple computers, a switch is not able to learn the port for the virtual NLB cluster MAC and is forced to send the packets destined for the NLB MAC to all ports of a switch to make sure packets get to the right destination
Multicast – NLB adds a layer 2 MAC address to the NIC of each node. Each NLB cluster node basically has two MAC addresses, its real one and its NLB generated address. With multicast, you can create static entries in the switch so that it sends the packets only to members of the NLB cluster. Mapping the address to the ports being used by the NLB cluster stops all ports from being flooded. Only the mapped ports will receive the packets for the NLB cluster instead of all ports in the switch. If you don’t create the static entries, it will cause switch flooding just like in unicast.
should be “none” not “client”
Disabling affinity allows for improved load balancing because it allows multiple connections from the same client to be handled concurrently by different cluster hosts. To maximize scaled performance, disable client affinity (using the None option) when it is not needed.
Agreed
Affinity should be set to None, having it like this allows every node to respond to incoming requests.
Affinity:NONE
Mode:Multicast