HOTSPOT
Yournetwork 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:
<map><m x1=”68″ x2=”111″ y1=”38″ y2=”60″ ss=”0″ a=”0″ /><m x1=”70″ x2=”146″
y1=”163″ y2=”184″ ss=”0″ a=”0″ /></map>The Affinity parameter is applicable only for the Multiple hosts filtering mode.
/ The Single option specifies that NLB should direct multiple requests from the same client IP
address to the same cluster host.
Network Load Balancing Manager Properties
https://technet.microsoft.com/en-us/library/cc771709.aspx
the answer area worng :
Affinity :
– None
– Client
– Class C
Mode :
– Unicast
– Multicast
I think the answer : Class C & Multicast
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If you don’t 100% know the correct answer DO NOT comment what you THINK it is.
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Peggy contributed by correcting the question.
No one “100% know the correct answer” everyone’s saying what they think it is.
I don’t remember seeing any contributions from “Soccer Mum 69” on other questions. So no useful contributions then.
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Isn’t “Class C” an old Affinity option?
According to the article, they are:
– None
– Single
– Network
I agree multicast is the best option “to minimize port flooding”.
No mention that the filtering mode is set to “multiple hosts”? If not, I think Affinity should remain “single”.
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single affinity – clients will connect to same host,
none – clients will connect to any host
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You need to ensure that the connections to WebApp1 are distributed evenly between the nodes.
The solution must minimize port flooding. The Affinity is None since we will have an even distribution. The port flooding I dont know but I will go with multicast
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Affinity: None
Mode: Unicast
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According to this Technet article (https://technet.microsoft.com/en-us/library/bb687542.aspx), the Affinity options are not correct. They should be:
None – Client connects to any member in the cluster the NLB decides without any preference by the client
Single – Client always connects to the same member
Class C – As you might suspect, NLB associates clients with particular members by using the Class C portion of the client’s IP address.
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I should have noted in my previous comment that the answer should then be “None” and “Unicast,” though “None” is not one of the options.
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Yes, I should clarify that I meant “multicast”, not unicast, sorry, lol
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The exibit is wrong for the Affinity parameter (None-Single-Network), anyway:
– Cluster operation mode is “Multicast” (minimize port flooding)
– Filtering mode is implicitly “Multiple hosts” (mandatory for distributing the network load among multiple hosts, even if not mentioned in the question. The Affinity parameter is applicable only for the Multiple hosts filtering mode.)
– Affinity parameter is “Single” for the reasons above:
The key is “secure web Application” that means (at network level) https protocol.
A load balanced https site (application) needs session persistence, that, in a NLB cluster, can be achieved through “Single” or “Network” affinity options.
“Single” is the right choice because offers more session spread across hosts, as described in Technet:
“The Single option specifies that NLB should direct multiple requests from the same client IP address to the same cluster host.
…
The Network option specifies that NLB direct multiple requests from the same TCP/IP Class C address range to the same cluster host. Enabling Network affinity instead of Single affinity ensures that clients that use multiple proxy servers to access the cluster have their TCP connections directed to the same cluster host.
…
Enabling Single or Network affinity ensures that only one cluster host handles all connections that are part of the same client session. This is important if the server application that is running on the cluster host maintains a session state (such as server cookies) between connections.”
I would like to stress that the client->host association is related to a single client session (“all connections that are part of the same client session”), so the cluster can balance multiple concurrent connections. The first client goes to Server1, a second client goes to Server2, and so on.
IMHO answer is correct : Single – Multicast.
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I passed the 70-412 today (920) and I encountered that question.
I can confirm that “affinity” options are:
– None
– Client
– Class C
My score in “Configure and Manage High Availability” was under 100%, so I can’t confirm my answer (none, multicast) is correct.
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The option none would be stateless, so it would not acomplish “WebApp1 saves user state information in a central database.”.
For Stateful (saves user state information) the option must be never none.
From the 412 student book:
Affinity
Affinity determines how the NLB cluster distributes requests from a specific client. Affinity settings only come into effect when you use the multiple hosts filtering mode. You can select from the following affinity modes:
• None. In this mode, any cluster node responds to any client request, even if the client is reconnecting after an interruption. For example, the first webpage on a web application might be retrieved from the third node, the second webpage from the first node, and the third webpage from the second node. This affinity mode is suitable for stateless applications.
• Single. When you use this affinity mode, a single cluster node handles all requests from a single client. For example, if the third node in a cluster handles a client’s first request, then all subsequent requests are also handled by that node. This affinity mode is useful for stateful applications.
• Class C. When you set this mode, a single node will respond to all requests from a class C network (one that uses the 255.255.255.0 subnet mask). This mode is useful for stateful applications where the client is accessing the NLB cluster through load balanced proxy servers. These proxy servers will have different IP addresses, but they will be within the same class C (24-bit) subnet block.
You can only use Unicast with multiple NICs and diferent networks.
The reference “Both servers connect to the same switch.” it’s a clue for “they are on the same subnet” – we must assume.
Given answer is correct:
Single
Multicast
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Sorry for mistyping, my answer was:
single, multicast
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sorry: Single-Multicast
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Single-Multicast
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question says:
for “ensure that the connections to WebApp1 are distributed evenly between the nodes”, notice “evenly”
should be None
for “must minimize port flooding”
should be Multicast
so you are right.
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The “evenly” is put, so you don’t choose “class c”, which will direct all traffic from the subnet to a single node. “None”, as said above would render state losses when switching nodes and is not suitable for stateful apps, so the only logical and quite frankly OBVIOUS choices are single and multicast…
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P.S. in the context of this questions single=client, regardless of the exact terminology used in the question, meaning once a server picks up a client request, it handles it till the end of the session.
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http://blogs.msmvps.com/clusterhelp/2005/08/07/unicast-vs-multicast-original-posted-feb-21-2005/
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If you don’t 100% know the correct answer DO NOT comment what you THINK it is.
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What a useless approach to problem solving!
Let us know YOUR, indisputable sentence, please.
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I thing the answer is correct b\c the question says “WebApp1 are distributed evenly between the nodes” and @ Soccer Mum 69 ur comment is not useful please leave us
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p.s.
Free 391q dumps from Google Drive:
https://drive.google.com/open?id=0B-ob6L_QjGLpfm94alk1eU9xWjFYRkVoNkl0cjRiOXZRRjVkUXNXTklicDdKZDJwRGJCM1k
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State information is stored in shared database so affinity should be none.
To minimize port flooding, choose multicast.
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Agree with yzz.
Affinity is none because the load is spread evenly. Single won’t necessarily have an even load because clients will be locked to a certain node. State information is stored in a central database so it doesn’t matter that state information won’t be on a particular node.
Multicast to minimize port flooding.
https://technet.microsoft.com/en-us/library/bb687542.aspx
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I agree with Joe that single/unicast is correct.
I watched the CBTNuggets70-412 Exam Videos and this is what Greg says about the Unicast, Multicast and IGMP Mulitcast:
“Unicast is in many ways probably the best of that three in terms of the amount of traffic that is generated on the subnet. Multicast is one of those protocols that the network team loves to hate, because Multicast has a tendency to flood the switches. This flooding can be minimized when your switches support IGMP multicast….”
From:
https://msdn.microsoft.com/en-us/library/bb742455.aspx
“when Network Load Balancing uses multicast mode, switches often flood all ports by default to deliver multicast traffic.”
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I never heard of multicast reducing port flooding/network traffic until I started reading these comments.
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No Joe says Multicast is correct in his next comment and he is correct.
Below is from the same url that you posted.
Network Load Balancing’s unicast mode induces switch flooding in order to simultaneously deliver incoming network traffic to all cluster hosts. Also, when Network Load Balancing uses multicast mode, switches often flood all ports by default to deliver multicast traffic. However, Network Load Balancing’s multicast mode gives the system administrator the opportunity to limit switch flooding by configuring a virtual LAN within the switch for the ports corresponding to the cluster hosts. This can be accomplished by manually programming the switch or by using the Internet Group Management Protocol (IGMP) or the GARP (Generic Attribute Registration Protocol) Multicast Registration Protocol (GMRP). The current version of Network Load Balancing does not provide automatic support for IGMP or GMRP.
And from 70-412 book
Another mode available is the Internet Group Management Protocol Multicast mode
which is a special form of multicast mode that prevents the network switch from flooding with traffic. When you use IGMP multicast mode, traffic is forwarded only through the
switch ports that are part of the NLB cluster. However, to use IGMP multicast mode, you
need switch hardware that supports IGMP multicast mode.
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