Application Layer Communication

Definitions

  • Application layer communication: Communication between two different services. These services may be on the same server, or different servers – it doesn’t matter. Actually how it goes from one IP address to another is dealt with by the transport layer, usually using TCP/IP. To communicate between services on the same server, localhost:SERVICE_PORT is used.
  • Application layer protocol: A protocol used to perform application layer communication.

Protocols

HTTP

See HTTP.

gRPC

A high performance framework able to remotely call procedures on other services. It’s very useful for complicated microservice-based applications, but for simple websites it’s overkill. It uses HTTP/2 over TCP.

Apache Kafka

This is used for real-time data transferring between services at high throughput and speeds. It uses a binary TCP-based protocol as its transport layer.

API standards and guidelines

These can be implemented using any application layer protocol.

REST

Representational State Transfer (REST) is a set of guidelines for an API. An API that follows these guidelines is said to be RESTful. The main two guidelines are that it is stateless and is a uniform interface. APIs that use HTTP as their application layer protocol are often RESTful.

GraphQL

GraphQL is an API standard for querying graph data.

Links to this page
  • Webhosting

    To solve this, the microservices architecture can be used. This means that separate components are separate services. The main downside is they have to use some sort of application layer protocol to communicate with each other. See Application Layer Communication for more.