Scenario A: On-site connection to the production line (select second floor)

Within a robotic workstation, a PLC needs to communicate at high speed with 10 servo drives. Complex routing is not required; only extremely low latency and a stable ring network are needed. A two-level management system offers the best cost-performance ratio and lowest latency.

Scenario B: Factory Backbone Network/Aggregation Layer (Select three layers)

The factory has five production lines, each operating on an independent network segment. You need to aggregate data from these lines to the monitoring center, ensuring no broadcast interference occurs between different lines, while also enabling cross-segment access. This necessitates using a three-tier management architecture as the core node.

In today's world where industrial internet security is increasingly important, Layer 3 switches also serve as the outpost of a "security firewall":

ACL access control: Layer 3 switches can restrict who can access the core database based on IP address ranges, which is much more precise than the pure physical layer isolation of Layer 2.

Bandwidth suppression: When transmitting across network segments, Layer 3 switches can allocate bandwidth more precisely to prevent sudden traffic surges in one network segment from paralyzing the entire campus network.

In short:

"Layer 2 focuses on MAC addresses for faster processing, while Layer 3 focuses on IP addresses for broader management." If your network is simply a local interconnection of a few dozen devices, Layer 2 is sufficient; however, if you need to cross network segments, cross regions, or undertake large-scale campus planning, Layer 3 is a necessity.