East-West Traffic vs North-South Traffic

East-West Traffic and North-South Traffic are terms commonly used in computer networking and data centers to describe the direction and type of data flow.

1. East-West Traffic

East-West Traffic refers to the communication between different servers, containers, or application services within the same data center or private network. Typically, it describes the flow of data between services or applications.

• Characteristics:

  • Internal network traffic
  • Occurs within the data center or same local area network (LAN)
  • Typically does not pass through external firewalls or external routers
  • Mainly service-to-service communication in microservices architectures, such as database-to-application server communication
  • Example: Communication between web servers and database servers or communication between Pods in Kubernetes

• Example:

  • If a user accesses a website via a browser, the traffic from the browser (client) to the web server is usually North-South traffic. However, if the web server makes a request to the database server for data, that communication is East-West traffic.

2. North-South Traffic

North-South Traffic refers to the flow of data between external networks (like the internet or clients) and a data center or cloud service, or vice versa.

• Characteristics:

  • External-to-internal communication traffic
  • Typically passes through load balancers, gateways, firewalls, etc.
  • Mainly traffic related to user requests to access services
  • Example: User accesses a web application, or API requests come from the outside world to the internal services

• Example:

  • For example, when a user accesses an online shopping website through their browser, the traffic from the user’s device (client) to the web application is North-South traffic. This request may go through an external load balancer, entering the data center and reaching the web server.

Summary:

• East-West Traffic happens internally within the data center or private network, and it typically involves communication between services.
• North-South Traffic occurs between external clients (e.g., users) and the data center, usually involving interactions between public networks and internal services.