SFP (Small Form-factor Pluggable) is a hot-pluggable network interface module used in the network devices of today’s computer networks. In this lesson, we will focus on what is SFP? Why we use these network interface modules and what are the types of SPFs. As a network engineer, you will work with SPFs a lot, especially if you are working in a Service Provider network. So, this lesson is also important like network cabling and network connectors.
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Table of Contents
What is SFP?
SFP is the abbreviation of Small Form-factor Pluggable. It is hot-pluggable transceiver which is plugged into SFP port of a network device like router, switch etc. After plugging any Small Form-factor Pluggable to the related socket of the device, you can connect fiber optic cable to this Small Form-factor Pluggable.
What is the role of SFP here? In this scenario, SFP converts the serial electrical signals to serial optical signals and vice versa.
An SPF is generally used in service provider networks or to connect large network devices which manages many users. In a small Local Area Network, SPFs are rarely used.
SFP Types
There are different SFP types used in data networks. These Small Form-factor Pluggable types are given below:
- 100 Mbit/s SFP
- 1 Gbit/s SFP
- 10 Gbit/s SFP+
- 25 Gbit/s SFP28
- cSFP
- SFP-DD
What is 100 Mbit/s SPF?
Small Form-factor Pluggables that allows data transmission at a speed of 100 Mbit/s.
Multi-mode fiber, LC connector, with black or Beige color coding
- SX: 850 nm, max 550 m
Multi-mode fiber, LC connector, with blue color coding
- FX: 1300 nm, up to 5 km
- LFX: 1310 nm, up to 5 km
Single-mode fiber, LC connector, with blue color coding
- LX: 1310 nm, up to 10 km
- EX: 1310 nm, up to 40 km
Single-mode fiber, LC connector, with green color coding
- ZX: 1550 nm, up to 80 km
- EZX: 1550 nm, up to 160 km
Single-mode fiber, LC connector, Bi-Directional, with blue and yellow color coding
- BX: 1550 nm/1310 nm, up to 10-40 km.
Copper twisted-pair cabling, 8P8C (RJ-45) connector
- 100BASE-TX: up to 100m.
What is 1 Gbit/s SPF?
Small Form-factor Pluggables that allows data transmission at 1 Gbit/s transmission speed.
1 to 1.25 Gbit/s multi-mode fiber, LC connector, with black or beige extraction lever
- SX: 850 nm, max 550 m at 1.25 Gbit/s
1 to 1.25 Gbit/s multi-mode fiber, LC connector, extraction lever colors not standardized
- SX+/MX/LSX/LX: 1310 nm, for a distance up to 2 km
1 to 2.5 Gbit/s single-mode fiber, LC connector, with blue extraction lever
- LX: 1310 nm, up to 10 km
- EX: 1310 nm, up to 40 km
- ZX: 1550 nm, up to 80 km
- EZX: 1550 nm, up to 160 km
- BX: 1490 nm/1310 nm, up to 10 km, 1550 nm, up to 80 km.
- 1550 nm 40 km (XD), 80 km (ZX), 120 km (EX or EZX)
- SFSW
What is 10 Gbit/s SFP+?
10 Gbit/s SFP+ (enhanced small form-factor pluggable) is the enhanced version of Small Form-factor Pluggable. The data rates that SFP+ support is up to 16 Gbit/s.
What is 25 Gbit/s SFP28?
SFP28 is a 25 Gbit/s interface which evolved from the 100Gbit Ethernet which is implemented with 4 by 25 Gbit/s data lanes.
What is cSFP?
cSFP is the abbreviation of compact small form-factor pluggable. It allows two independent bidirectional channels per port. It is manly used to increase port density.
What is SFP-DD?
SFP-DD is stands for small form-factor pluggable double density. It doubles port density.
Copper SFP vs Fiber SFP
SFP modules can be used with different transmission media depending on the transceiver type. Fiber SFP modules use fiber optic cables and optical connectors such as LC, while copper SFP modules can provide Ethernet connectivity over twisted-pair copper cables using an RJ45 interface.
Copper SFP modules are useful when a switch or router has an available SFP port but the network connection requires copper Ethernet. Fiber SFP modules, on the other hand, are commonly preferred for longer distances, backbone links and environments where fiber connectivity is required.
| Feature | Copper SFP | Fiber SFP |
| Transmission Media | Twisted-Pair Copper | Fiber Optic Cable |
| Common Connector | RJ45 | LC |
| Typical Use | Short-Distance Ethernet | Backbone and Longer-Distance Links |
| Electrical / Optical | Electrical | Optical |
You can learn more about RJ45 pinouts, Ethernet wiring, T568A/T568B standards and connector types in our RJ45 Connector guide.
Frequently Asked Questions About SPFs
What is Data Rate?
Data rate is the speed of SPF. For example, for 100Base-FX, data rate is 100 Mbit/s.
What is Distance used with SFP?
According to SPF type, distance is the supported distance of SPF.
What is Hot-swappable?
Hot-swappable means that we can insert or remove Small Form-factor Pluggable to the device without power down.
What is an SFP Port Used For?
An SFP port is used to install an SFP transceiver and connect a network device to copper or fiber optic links. Depending on the installed module, an Small Form-factor Pluggable Transceiver port can support different cable types, transmission distances and network applications. SFP ports are commonly found on switches and routers, especially for uplinks and backbone connections.
Is SFP Fiber Optic?
Small Form-factor Pluggable Transceiver is not exclusively fiber optic. Many SFP modules use fiber optic cables, but copper SFP transceivers are also available. Fiber SFP modules commonly use optical connectors such as LC, while copper Ethernet Small Form-factor Pluggable Transceiver modules can use an RJ45 interface.
Can I Plug SFP Into Ethernet?
An SFP module is inserted into a compatible SFP port on a switch, router or other network device. Ethernet can then operate through that Small Form-factor Pluggable Transceiver interface using a compatible fiber or copper transceiver. For example, a copper SFP module with an RJ45 interface can provide Ethernet connectivity over twisted-pair copper cable.
How Does SFP Work?
An SFP module acts as a removable transceiver between a network device and the transmission medium. It converts signals between the networking equipment and the connected copper or fiber link. The type of SFP determines characteristics such as supported data rate, wavelength, transmission medium and maximum distance.
Is SFP+ Faster Than RJ45?
Not necessarily, because SFP+ and RJ45 describe different things. SFP+ is a transceiver interface commonly associated with 10 Gigabit Ethernet, while RJ45 is a connector commonly used for copper Ethernet. Both SFP+ and RJ45-based connections can support 10 Gigabit Ethernet when compatible equipment and cabling are used. SFP+ fiber or DAC connections, however, are often preferred for certain high-performance and data center applications.
Can a 10G SFP+ Run at 1G?
It depends on the network device and transceiver. Some SFP+ ports support both 10 Gbps and 1 Gbps operation with compatible modules, while others are limited to specific speeds. Always check the switch or router specifications and the transceiver compatibility before using a 1G SFP module in an SFP+ port.
You can also check What is Power over Ethernet (PoE) Lesson!
To Start Learning Computer Networks, Cisco CCNA Course and Packet Tracer Configuration Course Can Be Perfect!
Gokhan Kosem is a Network Engineer, Instructor and the Founder of IPCisco.com with 15+ years of experience in Cisco, Nokia, Huawei, Juniper, Linux, Service Provider Networks, Routing and Switching technologies.
He has worked on the backbone networks of major service providers and network vendors including Nortel, Alcatel-Lucent (Nokia) and has extensive hands-on experience with Cisco, Huawei, Juniper and Nokia networking technologies.
He has trained thousands of networking students worldwide through IPCisco.com, Udemy, books, labs, quizzes, and educational content across multiple social media platforms.
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