Explore core principles and techniques of load balancing in network systems with this quiz, designed to clarify routing methods, distribution algorithms, and basic terminology. Improve your understanding of how network resources are efficiently managed and optimized for reliability and performance.
What does load balancing most commonly refer to in the context of network systems?
Explanation: Load balancing in network systems refers to distributing incoming network traffic evenly across multiple servers to optimize resource utilization and avoid overload. Blocking unauthorized access is related to network security, not load balancing. Compressing data is a form of optimization but not load balancing. Storing copies of data on different servers is called replication, which is different from load balancing.
What is the main goal of using a load balancer in a network infrastructure?
Explanation: The primary goal of a load balancer is to increase the availability and reliability of networked services by distributing requests across multiple servers. Having a single server handle all requests defeats the purpose and reduces redundancy. Increasing downtime goes against the function of a load balancer, and intentionally slowing response time is not desirable or related to this concept.
In the Round Robin load balancing algorithm, how are client requests assigned to servers?
Explanation: Round Robin assigns each new client request to the next server in a cyclical order, making it fair and simple. Random selection does not follow an order, and constantly assigning to the last server would overload it. Picking servers based on the smallest name is not a recognized load balancing practice.
Why do load balancers often perform health checks on backend servers?
Explanation: Health checks verify that backend servers are working correctly before routing any traffic to them, preventing failures in service delivery. Encrypting data is a security process, not directly related to health checks. Updating client applications and backing up configurations are maintenance tasks, not typical functions of health checks performed by load balancers.
Which type of load balancer makes distribution decisions based on IP address and TCP/UDP ports?
Explanation: Layer 4 load balancers make decisions based on network and transport information such as IP addresses and port numbers. Layer 7 deals with application content, while Layer 6 and Layer 1 are responsible for data format and physical transmission, respectively. Layer 4 is correct because it matches the distribution based on network information.
What is the main reason for enabling session persistence (sticky sessions) on a load balancer?
Explanation: Session persistence makes sure that requests from the same user are directed to the same server during a session, which is important for certain applications that maintain user state. Preventing connections or shutting down servers is not the purpose of sticky sessions. Random distribution ignores user session context and would break application consistency.
Which feature in load balancing allows traffic to reroute automatically if a server fails?
Explanation: A failover mechanism detects when a server is down and reroutes requests to healthy servers, maintaining availability. Data fragmentation breaks data into smaller pieces for transmission but does not handle rerouting. Static routing uses fixed paths and cannot adapt to server failures. Bandwidth limiting manages traffic speeds, not server failure.
What is a key characteristic of DNS-based load balancing in network systems?
Explanation: DNS-based load balancing provides multiple IP addresses for a single domain, allowing clients to be directed to different servers. Encryption of domain names is not generally handled by DNS-based balancing. Manual client configuration is unnecessary when using DNS. Real-time updates are not guaranteed as DNS responses are often cached by clients and resolvers.
Which of these is a common performance benefit of implementing load balancing in a web application scenario?
Explanation: Load balancing spreads the workload across multiple servers, reducing individual server strain and resulting in faster response times. The technique does not increase storage, control compression, or advocate removing important security measures like firewalls. Only sharing workload directly relates to improved performance.
How does a load balancer using the 'least connections' algorithm choose a server for a new incoming request?
Explanation: The 'least connections' algorithm assigns new requests to the server with the fewest ongoing connections, balancing the load dynamically. Choosing servers with the highest CPU usage or by hardware age is inefficient and not supported. Assigning by alphabetical order does not consider workload and is not used in this algorithm.