Lesson 2

Using Network Load Balancing

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2. Which of the following Nlb.exe commands do you use to shut down NLB opera-

tions on a cluster server without interrupting transactions currently in progress?

a. Nlb drain

b. Nlb params

c. Nlb drainstop

d. Nlb queryport

3. How long does it take a Network Load Balancing cluster to begin the convergence

process after one of the servers in the cluster fails?

Lesson Summary

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Network Load Balancing works by creating a virtual network adapter with IP and

MAC addresses that represent the cluster as a single unit.

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When NLB is running in unicast mode, the service replaces the network interface

adapter’s MAC address with the cluster MAC address, making ordinary communi-

cations between cluster servers impossible.

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When NLB is running in multicast mode, the service uses both the network inter-

face adapter’s MAC address and the cluster MAC address, enabling cluster servers

to communicate normally.

■

Although NLB can function with a single network interface adapter installed in

each server, using multiple adapters in each server can prevent network perfor-

mance degradation.

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NLB cluster servers transmit a heartbeat message once every second. If a server

fails to transmit five successive heartbeats, the other servers in the cluster begin

the convergence process, redistributing the incoming traffic among the remaining

servers.