What is nlb in windows 2008

This should be done manually by running a script. Automatically load balances when new hosts are added or removed and this is done within 10 seconds.

NLB can be enabled on multiple network adapters. This allows you to configure different NLB Cluster. NLB can operate in two modes - Unicast or Multicast but both the modes can't be enabled at the same time.

Unicast is the default mode. This traffic is received by all the hosts in cluster and NLB driver filter the traffic as per the Port Rules defined. NLB nodes don't communicate with each other for incoming traffic coming from client because NLB is enabled on all the nodes. A statistically mapping rule is created on each host to distribute incoming traffic.

This mapping remains the same unless there's a change in the cluster for example, node removed or added. Convergence is a process to rebuild the cluster state.

This process invokes when there's a change in cluster for example, node fails, leaves, or rejoin the cluster. In this process, the following actions are taken by cluster:.

During this process, remaining host continues to handle incoming client traffic. If a host is added to the cluster, convergence allows this host to receive its share of the load-balanced traffic. Expansion of the cluster doesn't affect ongoing cluster operations and is achieved transparently to both Internet clients and to server applications.

The cluster has converged, and the responding host is the current default the highest priority host without a drainstop command in progress. The cluster has converged, and the responding host is not the default host. Displays information about a given port rule. The first parameter specifies which port rule to query. Specify the port rule by using a port number that is within the range of the port rule that you want to query.

The default is all VIPs. However, if a particular port rule is assigned to only a specific VIP as opposed to all VIPs you must specify the appropriate VIP in order for the port rule to be found by this command.

The information returned includes information regarding if the port rule was found or an indication that the port rule was not found, the state of the port rule Enabled, Disabled or Draining , and a count of packets accepted and dropped on that port rule..

Reloads the NLB driver's current parameters from the registry. Cluster operations on the local host are automatically stopped and restarted if necessary. If an error exists in the parameters, the host will not join the cluster, and a warning is displayed.

If this should occur, open the NLB Properties dialog box to fix the problem. Displays extensive information about your current NLB parameters, cluster state, and past cluster activity.

The last several event log records produced by NLB are shown, including the binary data attached to those records.

This command is designed to assist in technical support and debugging. The registry information retrieved by the display command shows what the next state of NLB would be if a reload or some other operation that causes the driver to read the registry were to be performed. The registry information might or might not be the current state of NLB. Displays information about your current NLB configuration. This command is similar to the display command, however, instead of retrieving the information from the registry, the params command queries directly from the kernel-mode driver.

The information displayed is therefore the current state of NLB. In addition to the configuration information, the nlb params command displays state variables from the kernel, including the current number of connections being maintained by NLB and the number of dynamic allocations that have been necessary for connection tracking. Displays the media access control address corresponding to the specified cluster name or IP address. If multicast support is enabled, the multicast media access control address is used by NLB for cluster operations.

When Extended Affinity is enabled and node membership in the NLB cluster changes configuration change, adding or removing nodes, etc. Extended Affinity allows clients to keep affinity to a cluster host even if there are no active, existing connections from the client to the host.

The following sections describe how NLB supports high availability, scalability, and manageability of the clustered servers that run these applications. A high availability system reliably provides an acceptable level of service with minimal downtime. To provide high availability, NLB includes built-in features that can automatically:. Scalability is the measure of how well a computer, service, or application can grow to meet increasing performance demands. For NLB clusters, scalability is the ability to incrementally add one or more systems to an existing cluster when the overall load of the cluster exceeds its capabilities.

To support scalability, you can do the following with NLB:. Balance multiple server load requests from the same client or from several clients across multiple hosts in the cluster.

Enable high performance and low overhead through a fully pipelined implementation. Pipelining allows requests to be sent to the NLB cluster without waiting for a response to a previous request.

Specify the load balancing behavior for a single IP port or group of ports by using port management rules. Define different port rules for each website. If you use the same set of load-balanced servers for multiple applications or websites, port rules are based on the destination virtual IP address using virtual clusters. Direct all client requests to a single host by using optional, single-host rules. NLB routes client requests to a particular host that is running specific applications.