TCP/UDP Load Balancer (Layer 4) in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Architecture

intermediate

Identify the main components of a GCP TCP/UDP Load Balancer

Which of the following components is NOT part of the typical architecture of a GCP TCP/UDP Load Balancer?

A Application layer firewall for HTTP header inspection

B Backend service with instance groups or network endpoint groups

C Health checks to monitor backend instance availability

D Frontend IP and port to receive client traffic

💡 Hint

Think about what Layer 4 load balancing means and what it does not inspect.

GCP TCP/UDP Load Balancer operates at Layer 4, which means it does not inspect application layer data such as HTTP headers. Therefore, application layer firewalls are not part of its architecture.

❓ scaling

intermediate

Scaling considerations for GCP TCP/UDP Load Balancer

When scaling a GCP TCP/UDP Load Balancer to handle millions of concurrent connections, which factor is MOST critical to ensure performance?

A Using a global forwarding rule with multiple backend regions

B Increasing the number of backend instances without adjusting health checks

C Configuring session affinity to the client IP for all connections

D Deploying a single backend instance with high CPU capacity

💡 Hint

Consider how GCP distributes traffic globally and handles failover.

Using a global forwarding rule with multiple backend regions allows the load balancer to distribute traffic efficiently and scale globally, which is critical for handling millions of connections.

❓ tradeoff

advanced

Tradeoff between session affinity and load distribution

What is the main tradeoff when enabling client IP-based session affinity on a GCP TCP/UDP Load Balancer?

A Improved load distribution but increased latency

B Reduced backend stickiness but better fault tolerance

C Lower resource usage but higher risk of dropped connections

D Better session persistence but potential uneven load across backends

💡 Hint

Think about how session affinity affects traffic routing consistency.

Client IP-based session affinity ensures the same client connects to the same backend, improving session persistence. However, it can cause uneven load distribution if some clients generate more traffic.

🧠 Conceptual

advanced

Understanding health checks in GCP TCP/UDP Load Balancer

Which statement BEST describes the role of health checks in a GCP TCP/UDP Load Balancer setup?

A Health checks automatically restart unhealthy backend instances

B Health checks determine backend availability by probing IP and port connectivity

C Health checks are optional and do not affect traffic routing decisions

D Health checks inspect application payloads to verify backend correctness

💡 Hint

Consider what Layer 4 load balancers can check about backend instances.

Health checks for TCP/UDP load balancers verify backend availability by checking if the backend IP and port respond, without inspecting application data.

❓ estimation

expert

Estimating backend capacity for a GCP TCP/UDP Load Balancer

You expect 10 million concurrent TCP connections distributed evenly across 5 backend instance groups. Each instance can handle 50,000 concurrent connections. How many instances are needed in total to handle the load with a 20% safety margin?

A 200 instances

B 250 instances

C 240 instances

D 300 instances

💡 Hint

Calculate total instances needed, then add 20% safety margin.

10,000,000 connections / 50,000 per instance = 200 instances needed. Adding 20% safety margin: 200 * 1.2 = 240 instances total.