Can access switches be connected in series

Connecting access switches in series is generally not recommended due to potential performance, redundancy, and fault-tolerance issues.

Understanding Series Connection

In a typical network, access switches connect end devices to the LAN and then uplink to distribution or aggregation switches, which in turn connect to the core layer. When access switches are connected in series (daisy-chained), traffic from devices on downstream switches must pass through upstream switches to reach the rest of the network. This setup can create single points of failure, as a failure in any upstream switch can isolate all downstream devices.

Implications of Series Connection

Performance Bottlenecks: Traffic from multiple downstream switches converges on a single uplink, potentially saturating the link and causing latency or packet loss. Reduced Redundancy: Without redundant uplinks, a single switch failure can disrupt connectivity for multiple devices. Complex Troubleshooting: Identifying network issues becomes more difficult because multiple switches depend on each other for connectivity.

Limited Scalability: Adding more switches in series increases the risk of congestion and failure propagation, making the network harder to scale.

Best Practices

Star Topology: Connect each access switch directly to a distribution or aggregation switch rather than daisy-chaining. This improves performance, redundancy, and fault isolation. Redundant Uplinks: Use dual uplinks from access switches to distribution switches to ensure resiliency.

Stackable Switches: Consider stackable access switches (e.g., Cisco C9350 Series) that behave as a single logical switch, simplifying management and reducing the risks associated with series connections.

Segmentation and VLA

Ns: Properly segment traffic using VLANs to reduce broadcast domains and improve network efficiency.

Conclusion

While connecting access switches in series may work in small or temporary setups, it is not recommended for enterprise or campus networks due to performance, redundancy, and scalability concerns. Following hierarchical design principles with direct uplinks to distribution switches and implementing redundancy ensures a more reliable and manageable network.