A Comprehensive Overview of Ethernet Switch Port Types
Dec 20, 20211 min read
The forms and data rates of Ethernet switches vary, and the switch port types also do. This article helps IT planners and network administrators make better hardware choices. It introduces common Ethernet switch port types. We will look at data rates, functions, and network architecture. This guide is especially useful when selecting a 1G campus switch or upgrading to higher-performance Ethernet solutions.
Differentiate Ethernet Switch Port Types by Data Rates
Data rate is a vitally important factor for Ethernet switch interface, and it can usually vary from 1G, 10G, 25G, 40G to 100G and beyond. The following are some mainstream interface types of these different data rates.
RJ45 Port
Enterprise LANs use the RJ45 port on 100/1000BASE switches. It connects access layer devices and uplinks from desktop switches or directly to end devices. A standard Ethernet cable (Cat5/5e/6/6a cable) is often used when connecting two RJ45 ports on Gigabit switches. RJ45 ports remain essential for modern 1G campus switch deployments, especially in educational institutions and branch offices where cost-effectiveness and reliability are priorities.
SFP Port
People also call the SFP port, or small form-factor pluggable, a mini-GBIC. The SFP port is commonly found on Gigabit Ethernet switches and is primarily used for fiber optic device connections or for uplinking 1G switches to aggregation/core layer devices, providing higher-bandwidth links.
You can add a compatible SFP transceiver module to the SFP port of Ethernet switches. This can be a fiber optic SFP or a copper SFP, enabling you to create long-distance fiber links or short-range copper links. SFP ports offer cost-effective network expansion without replacing the switch chassis.
The SFP slot is extremely flexible. This makes it useful for business networks, media converters, and anywhere that needs scalable port options.
SFP+ Port
SFP+ port (small form-factor pluggable plus) is an enhanced version of SFP port, supporting higher speeds up to 10Gbps. In terms of SFP vs SFP+ compatibility, SFP+ ports often accept SFP optics but at a reduced speed of 1Gbps. However, you cannot plug an SFP+ transceiver into an SFP port because SFP+ does not support speeds less than 1Gbps.
Network engineers commonly use SFP+ ports in aggregation switches and 10G campus backbones. They are popular because of their small size and flexible connections.
SFP28 Port
An SFP28 port is an enhanced version of the SFP+ interface, designed for 25Gbps data transmission over a single lane while maintaining the same compact form factor.
Compared to traditional SFP+ ports that support up to 10Gbps, SFP28 ports significantly boost bandwidth without requiring additional space or major changes to existing infrastructure.
On Ethernet switches, SFP28 ports play a critical role in enabling high-speed, high-density connectivity. They allow seamless connection to 25G servers, network interface cards (NICs), or optical fiber cabling, making them well-suited for top-of-rack (ToR) or leaf switches in modern data centers. SFP28 ports help networks transition smoothly from 10G to 25G and beyond, offering greater scalability, improved energy efficiency, and better return on investment—all while optimizing port utilization in high-performance switching environments.
QSFP+ Port
The QSFP+ port is a high-density, pluggable interface on Ethernet switches, mainly used for 40Gbps data transmission. It features four 10Gbps lanes, enabling 40G Ethernet connectivity in a compact form factor.
Commonly found on aggregation or core switches in data centers, QSFP+ ports are ideal for spine-leaf architectures, where spine nodes use QSFP+/QSFP28 ports to connect multiple leaf nodes. Each QSFP+ port can also be split into four 10G SFP+ connections using breakout cables, offering flexible connectivity and saving rack space.
Compared to four separate SFP+ ports, QSFP+ increases port density and power efficiency, making it a space- and energy-saving solution for high-performance networks.
QSFP28 Port
A QSFP28 port is a fast connection often used in 100G Ethernet and InfiniBand EDR applications.
It supports four lanes of 25Gbps transmission, delivering an aggregated bandwidth of 100Gbps (4×25Gbps) per port.
In some setups, QSFP28 modules can support breakout modes of 4×25G or 2×50G. This provides backward compatibility and flexibility for deployment.
A network switch may support diversified ports. Here take some gigabit switch, 10GB Ethernet switch and 40G/100G Ethernet switches as examples to show the switch port types and numbers that a network switch may have.
RJ45 Port | 24 | / | / | / |
SFP Port | / | / | / | / |
SFP+ Port | 4 | 20 | / | / |
SFP28 Port | / | 4 | / | 48 |
QSFP+ Port | / | 2 | 16 | / |
QSFP28 Port | / | / | 8 | 8 |
Differentiate Ethernet Switch Port Types by Functions
Functionality and application scenarios are important when identifying Ethernet switch port types. The same physical interface can have multiple roles.
Understanding port features such as combo ports, stacking ports, and PoE ports helps optimize switch deployment and network design.
Combo Port
A combo port is a flexible interface. It has both an RJ45 Ethernet port and an SFP slot. These two share the same switch fabric and logical port.
Only one interface can be active at a time. The combo port offers flexible connectivity options. It can support either copper-based links or fiber uplinks, depending on the network setup.
This setup helps users make the most of port utility. It does this without using extra switch resources. This makes it perfect for access switches and small network environments.
Stack Port
A stack port is a special port on a switch. It connects to other stackable switches. This lets them work together as one system.
These switch stacking configurations combine multiple physical units into a single logical switch, expanding both port capacity and management scalability.
This group of switches shows the characteristics of a single switch but has the port capacity of the sum of the combined switches. Additionally, a stack port can be an uplink port, but some switches may have a dedicated port for stacking.
For example, FS S3900 Series switches use uplink ports for stacking. They can connect with DAC cables, AOC cables, or fiber transceivers.
Network administrators commonly use stack ports in campus networks, enterprise cores, or environments that require simplified network management.
PoE Port
Power over Ethernet (PoE) ports let you send both power and data through one Cat5e or Cat6 cable. This reduces the number of cables needed and lowers costs.
PoE port on Ethernet switches support standard protocols like IEEE 802.3af (up to 15.4W per port) and IEEE 802.3at, also known as PoE+ (up to 30W per port).
Power loss occurs over cable distance, so the minimum guaranteed power at the powered device (PD) is 12.95W for PoE, 25.5W for PoE+, and typically 51W to 71.3W for PoE++, depending on the Type and cable quality.
Many users rely on PoE ports to power IP cameras, VoIP phones, wireless access points, and other network devices, especially where running separate power lines is impractical.
Differentiate Ethernet Switch Port Types by Switch Port Mode
Access Port
An access port connects end-user devices like desktop computers, laptops, and network printers. It works only on an access VLAN link.
The system sets itself up to join one VLAN (Virtual LAN). It sends untagged Ethernet frames within that VLAN.
An access port supports only one access VLAN. It automatically discards frames that do not belong to that VLAN.
Trunk Port
Network switches usually connect using a trunk port. It can also link a switch to layer 3 devices like routers or firewalls. This feature enables trunk links.
It allows multiple VLANs to be carried over the same physical connection by using 802.1Q VLAN tagging, making it ideal for inter-switch communication.
The trunk port aggregates traffic from different VLANs, while the access port connects to a single VLAN.
Hybrid Port
A hybrid port combines the features of both access ports and trunk ports, making it suitable for connecting user endpoints as well as switches in enterprise networks.
This type of switch port supports untagged traffic like an access port and tagged VLAN traffic like a trunk port, enabling flexible VLAN segmentation across hybrid network environments.
Unlike standard trunk ports, a hybrid port allows more granular VLAN control, letting network administrators define how different tagged and untagged frames are processed on the same interface.
The diagram below illustrates how these three switch port modes are applied within a unified layered network architecture.
Selecting the Best Ethernet Switch Port Based on Your Needs
Understanding the differences between Ethernet switch port types is essential for selecting the most appropriate network switches for your specific needs.
When evaluating the right switch port configuration, consider both your current network demands and future scalability requirements, including bandwidth, device types, and VLAN setup.
Choosing the right switch port types and quantities ensures optimal network performance, cost-efficiency, and room for growth in enterprise or campus networks.
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