Assign a role before selecting a model
Access terminates devices; aggregation collects zones/buildings; the core carries inter-service and campus traffic. A compact project can combine roles only after checking its port and capacity map.
- Count RJ45, SFP, SFP+, SFP28 and QSFP interfaces at their required speeds.
- Treat combo fiber/copper interfaces as one shared interface, not two independent ports.
- Reserve physical uplinks for servers, gateway, redundancy and management.
Use the exact model suffix
Related family names can hide major differences in power, interface speed or environment.
- S5130S-28P-HPWR-EI-AC has GE uplinks and a370W PoE budget; do not substitute a similarly named lower-budget model.
- FS5500V2-24UXS6Y-EI has24 base2.5GE access ports, with a license upgrade on12 supported ports.
- Industrial temperature or IP ratings belong to the documented model, not the entire project.
Check contention and recovery
Adding a second supply protects only a subset of faults. Availability also depends on chassis, links, gateways, management and endpoints.
- Calculate summed access line rate and expected simultaneous traffic separately.
- Specify tested stacking/IRF/other failover topology with actual port consumption.
- List failure domains and agreed recovery tests; no unmeasured availability percentage.