Microservice transports in NestJS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Microservice Transport Protocols

Which of the following transport protocols is most suitable for low-latency, high-throughput communication between microservices in a distributed system?

A FTP (File Transfer Protocol)

B gRPC over HTTP/2

C SMTP (Simple Mail Transfer Protocol)

D HTTP/REST over TCP

💡 Hint

Think about protocols designed for fast, efficient communication with support for streaming and multiplexing.

gRPC uses HTTP/2 which supports multiplexing and binary framing, making it ideal for low-latency and high-throughput microservice communication. HTTP/REST is simpler but less efficient. SMTP and FTP are not designed for microservice communication.

❓ Architecture

intermediate

Choosing Transport for Event-Driven Microservices

You are designing an event-driven microservice system where services communicate asynchronously. Which transport mechanism below best supports asynchronous message passing with guaranteed delivery?

A gRPC Unary Calls

B HTTP Polling

C WebSockets

D RabbitMQ (AMQP protocol)

💡 Hint

Look for a message broker that supports queues and acknowledgments.

RabbitMQ uses AMQP which supports asynchronous messaging with guaranteed delivery and message acknowledgments. WebSockets and HTTP polling are less reliable for guaranteed delivery. gRPC unary calls are synchronous.

❓ scaling

advanced

Scaling Microservices with Transport Choices

When scaling microservices horizontally, which transport approach minimizes connection overhead and supports load balancing effectively?

A Multiple HTTP/1.1 connections per client

B Opening new TCP connections for each request

C Single persistent HTTP/2 connection with multiplexing

D Using UDP for all microservice communication

💡 Hint

Consider how connection reuse and multiplexing affect resource usage and load balancing.

HTTP/2 allows multiplexing many requests over a single persistent connection, reducing overhead and improving load balancing. HTTP/1.1 and opening new TCP connections increase overhead. UDP is unreliable and not suitable for most microservice communication.

❓ tradeoff

advanced

Tradeoffs Between Synchronous and Asynchronous Transports

Which statement correctly describes a tradeoff when choosing synchronous (e.g., HTTP/gRPC) versus asynchronous (e.g., message queues) transports for microservices?

A Asynchronous transports improve fault tolerance but increase message latency.

B Synchronous transports always guarantee message delivery, asynchronous never do.

C Synchronous transports are better for decoupling services than asynchronous transports.

D Asynchronous transports require services to be tightly coupled.

💡 Hint

Think about how asynchronous messaging affects timing and reliability.

Asynchronous transports improve fault tolerance by decoupling services and allowing retries, but they introduce latency due to queuing. Synchronous transports have lower latency but tighter coupling. Message delivery guarantees depend on implementation, not just sync/async.

❓ estimation

expert

Estimating Capacity for Microservice Transport Layer

You have a microservice system using RabbitMQ for asynchronous messaging. Each message is 1 KB. The system expects 10,000 messages per second. Estimate the minimum network bandwidth in Mbps required to handle this load without bottlenecks (assume 8 bits per byte).

A 80 Mbps

B 64 Mbps

C 100 Mbps

D 10 Mbps

💡 Hint

Calculate total bits per second: message size in bytes × 8 × messages per second, then convert to Mbps.

1 KB = 1024 bytes, so 1024 × 8 = 8192 bits per message. For 10,000 messages per second: 8192 × 10,000 = 81,920,000 bits per second ≈ 81.92 Mbps. The closest option is 80 Mbps.