Choose a switch by its role in the network (access, aggregation or data center), then match port count and speed, PoE power, uplink speed, layer 2 or layer 3 features, stacking and the software license tier. Getting the role right first narrows the choice quickly.
Switch roles
| Role | Where it sits | Typical ports | Key needs |
|---|---|---|---|
| Access (campus) | Wiring closets, near users and devices | 24 or 48 x 1G or multigigabit RJ45 | PoE, stacking, port security |
| Aggregation / distribution | Between access and core | 10G, 25G SFP ports | Layer 3 routing, redundancy, many uplinks |
| Core | Center of a campus network | 10G to 100G | High throughput, redundancy |
| Data center leaf (top of rack) | In each server rack | 10G or 25G down, 40G or 100G up | Low latency, deep port density, airflow options |
| Data center spine | Connects leaf switches | 100G or 400G | High-speed ports, routing at scale |
Browse networking switches, including campus and data center models.
Port count and speed
- Access ports: 1G RJ45 covers most desktops and phones. Multigigabit ports (2.5G and 5G) support newer Wi-Fi access points.
- Server ports: 10G and 25G SFP ports, with SFP28 now common in data centers. 10GBASE-T RJ45 suits racks with copper cabling.
- Plan for growth. Buy enough ports for the expected number of devices, plus spare ports for growth and failures.
PoE classes and power budgets
Power over Ethernet sends power and data on the same cable to phones, access points and cameras.
| Standard | Name | Power at switch port | Typical devices |
|---|---|---|---|
| IEEE 802.3af | PoE (Type 1) | 15.4 W | Phones, simple cameras |
| IEEE 802.3at | PoE+ (Type 2) | 30 W | Wi-Fi access points, PTZ cameras |
| IEEE 802.3bt | PoE++ Type 3 | 60 W | High-power access points, thin clients |
| IEEE 802.3bt | PoE++ Type 4 | 90 W | Displays, lighting, larger devices |
The power budget is the total PoE power the switch can deliver across all ports. A 48-port PoE+ switch does not always have enough budget to supply 30 W to every port at the same time. Check:
- The total PoE budget with the installed power supplies.
- Whether adding a second power supply raises the budget or only adds redundancy.
- The real draw of your devices, which is often below the class maximum.
Uplinks
Uplink ports connect the switch to the rest of the network. Common options are 10G SFP+, 25G SFP28, 40G QSFP+ and 100G QSFP28. Some switches use fixed uplinks; others take plug-in uplink modules.
As a rule of thumb, size uplinks so the ratio of access bandwidth to uplink bandwidth (the oversubscription ratio) suits the workload. Campus networks tolerate higher ratios than data centers. Remember to add the transceivers or cables for every uplink.
Layer 2 vs layer 3
- Layer 2 switches forward traffic within VLANs. Routing between VLANs is done by another device.
- Layer 3 switches also route between VLANs and networks. Basic layer 3 covers static routes and simple routing protocols. Advanced layer 3 adds protocols such as OSPF and BGP, and features such as VRFs.
Access switches often need layer 2 plus basic layer 3. Aggregation, core and data center switches usually need full layer 3. On many platforms, advanced routing depends on the license tier.
Stacking and redundancy
- Stacking joins several switches into one logical switch, managed as a single device. It is common in access layers. Stacks need stacking cables or modules, and usually require the same model family and software version.
- MLAG and similar features let two switches act as a pair for link aggregation without full stacking. They are common in aggregation and data center layers.
- Redundant power supplies and fans are standard in data center switches and optional on many campus models.
Data center specifics
- Airflow direction: data center switches come in front-to-back or back-to-front airflow. Match it to your hot and cold aisles. The direction is usually set by the fan and power supply part numbers.
- Latency and buffers: storage and high-performance workloads may need specific buffer sizes.
- Automation: check API and automation support if you manage the network with scripts or tools.
Licensing tiers
Many switch brands split features into license tiers, for example an essentials or base tier and an advanced tier. Some also use subscription licenses for management and analytics.
When buying refurbished or used switches:
- Check which license is installed and whether it transfers. Some licenses are tied to the original owner or a cloud account.
- Check whether a feature you need, such as advanced routing or stacking, requires a license you do not have.
- Software support and updates may require a contract with the manufacturer.
Your quote states which license tier is included, if any.
Refurbished and used switches
Switches are a common choice for refurbished purchase. Check the software version, license state, power supplies and fans, and ask for a port test if it matters to you. See new vs refurbished vs used and buying end-of-life hardware.
Checklist for your request
- Role: access, aggregation, core or data center.
- Number and speed of ports.
- PoE standard and total power needed.
- Uplink speed and number.
- Layer 2 or layer 3, and routing protocols needed.
- Stacking or redundancy requirements.
- Airflow direction for data center models.
- License tier.
- Transceivers, cables and power supplies needed with it.
Send your requirements or exact part numbers as an RFQ. Add optics from transceivers to the same request.