North-South and East-West Traffic
In networking, North-South traffic and East-West traffic describe the direction and type of data flow in a network environment. These terms are commonly used in data center and cloud networking to conceptualize the movement of data within and across different layers of infrastructure.
North-South Traffic
- Definition: Refers to traffic that flows between a data center (or a private network) and external networks (e.g., the Internet, branch offices, or external clients).
- Direction: Vertical movement, resembling the up-and-down movement on a map (north = up, south = down).
- Examples:
- A user accessing a website hosted in a data center.
- A mobile app connecting to a cloud server.
- VPN connections from remote offices to a corporate network.
- Characteristics:
- Involves external requests entering the network (ingress) and responses leaving the network (egress).
- Often needs to be secured with firewalls, intrusion detection/prevention systems, and load balancers.
East-West Traffic
- Definition: Refers to traffic that flows within a data center or a private network, typically between servers, virtual machines (VMs), or containers.
- Direction: Horizontal movement, resembling the left-to-right movement on a map.
- Examples:
- Communication between microservices in a cloud-native application.
- Data replication between database servers.
- VMs exchanging data within the same network segment.
- Characteristics:
- Generally internal to the infrastructure.
- Requires segmentation, monitoring, and security (e.g., micro-segmentation) to prevent lateral movement of threats within the network.
Key Differences
| Feature | North-South Traffic | East-West Traffic |
|---|---|---|
| Scope | External to internal or vice versa | Internal (within the data center) |
| Direction | Vertical (up-down) | Horizontal (left-right) |
| Security Focus | Firewalls, perimeter security | Micro-segmentation, internal monitoring |
| Performance Focus | Bandwidth management, latency optimization | Low-latency inter-server communication |
By understanding these traffic patterns, network architects can design and secure networks more effectively, optimizing performance and minimizing risks.