What is the use NLB | Windows server 2016 - Youronlinezone

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Network Load Balancing (NLB) transparently distributes traffic across multiple servers by using virtual IP addresses and a shared name with NLB, you gain fault tolerance and enhanced performance. It is often used with mission-critical web servers but can also be found with other types of servers.

A cluster has two or more servers known as nodes. Each node runs a separate copy of the desired service application such as a web server an FTP server, or a Secure Shell (SSH) / Remote Desktop Server. NLB is a scalable, high availability feature found in Windows Server 2016 It is considered scalable because you add additional servers to meet increasing demand.

Windows Sever 2016 NLB clusters can have between 2 and 32 nodes. When you create an NLB cluster, you create a virtual network address and adapter that is assigned to the entire cluster. As network requests are sent to the virtual network address, the requests are distributed across the nodes in the cluster. Based on your needs you can configure the cluster to even out the requests or you can configure one node to be preferred over another node.

NLB can detect the failure of cluster nodes by sending packets known as heartbeats. NLB cluster heartbeats are transmitted every second between nodes in the cluster. If a node misses five consecutive heartbeats, the node is automatically removed from the NLB cluster.

Configuring NLB Prerequisites:-

Although editions of windows Server 2016 support NLB and NLB supports running different editions of windows Server 2016, it is best practice to use computers with similar hardware specifications that run the same edition of the windows Server 2016.

To support NLB, your systems must use the following requirements

All hosts in the cluster must reside on the same subnet.

Within each cluster, all network adapters must be either multicast or unicast. You cannot

Have some nodes configured as multicast while other nodes are configured as unicast within a single cluster. We discuss multicast and unicast configuration later in the lesson.

If unicast mode is used, the network adapter that is used to handle client-to-cluster traffic must support changing its media access control MAC address.

The IP addresses assigned to the nodes must be static.

Configuring Filtering Mode and Affinity:-

Affinity determines how the servers are going to balance the load you use affinity settings when you use multiple filter mode.

When you configure port rules, you first select the filter mode. The filter mode specifies which host can be respond to request the filter mode includes the following.

Multiple hosts:-Permits all cluster hosts to actively respond to client requests. NLB nodes respond according to the weight assigned to each node. Because this allows the customizing of the affinity and load balancing, it is the most common mode used multiple hosts filtering increases availability and scalability, because you can increase capacity by adding nodes, and the cluster continues to function in the event of node failure.

Single host:- Allows only one cluster host (the host with the highest priority) in the cluster to actively respond to client requests. If the host fails, the host with the next highest priority takes over for the failed host. It is usually used to configure one host as the primary server and other hosts as backup servers. Single host rules increase availability, but do not increase scalability.

Disable:- Prevents the cluster from responding to a specific type of client traffic.

If you choose the multiple host filtering mode, you can then configure the affinity. When you configure affinity, you can choose one of the three options:

None:- Any cluster node responds to any client request, even if the client is reconnecting after an interruption. This option is suitable for stateless application, where the server that is servicing the request does not have to remember the previous events to complete the request. As a result, the client can jump from one server to another within the cluster without problem.

Single:- A single cluster node handles all requests from a single client. This option is useful for stateful applications where the status of a process or transaction is maintained through the entire connection including when using SSL and e-commerce shopping cart applications.

Class C :- A single node responds to all requests from a class C network (a network with a subnet of (255.255.255.0), often found when used with multiple proxy servers. This type of server is often used with cookie-based affinity or when a common database or session state server is used.

Configuring Cluster Operation Mode:-

On the Cluster Parameters tab, you configure the virtual IP address, subnet mask, and DNS name that the cluster will use. You also can configure the cluster operation mode, Which specifies whether a multicast MAC address should be used for cluster operations?

UNICAST MODE:-

When you configure an NLB cluster to use unicast mode, NLB replaces the network card’s Original MAC address and all cluster hosts use the same unicast MAC address. When you use Unicast mode with a single network adapter on each node, the computer can communicate Only with other computers within the same subnet

MULTICAST MODE:-

When an NLB host is in multicast mode, each NLB network adapter has two MAC addresses (The original MAC address and the virtual MAC address). However, when using multicast mode, some routers might see a unicast ip address with a multicast MAC address as an invalid Packet and reject the update to the ARP table. If this happens, the network administrators might need to manually add ARP entries to the router.

Internet Group Management Protocol Multicast Mode.

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.

Full from importance words.