Redundancy Models in the Distribution Layer

Jan 2005  •  Reading time: 6 min

The distribution layer plays a critical role in enterprise campus networks, acting as a bridge between access and core layers. In this post, we explore redundancy models that enhance reliability and maintainability in this tier.

What Is the Distribution Layer?

The distribution layer aggregates traffic from access switches and applies policies for routing, filtering, and QoS. Its design impacts overall network scalability and fault tolerance.

Redundancy Models

There are three key redundancy models for the distribution layer:

• Single Distribution: Simplest, but introduces a single point of failure.
• Dual Distribution without Routing: Redundancy without dynamic protocols—suitable for static environments.
• Dual Distribution with Routing: Uses routing protocols like OSPF or EIGRP for dynamic failover.

Design Considerations

Choose the model based on your network’s size, criticality, and budget. In small to mid-sized networks, dual distribution with routing offers the best mix of resiliency and scalability.

Conclusion

Redundancy in the distribution layer is not just about uptime; it’s about ensuring a robust architecture that supports business continuity. As networks evolve, these design principles remain foundational.

Eduardo Wnorowski is a technology consultant focused on network and infrastructure. He shares practical insights from the field for engineers and architects.