Difference between qsfp and sfp

 
SFP and QSFP both have the similar name 'SFP,' which implies that they have similar functions. The Quad Small Form-Factor Pluggable (QSFP) transceiver provides a variety of transmitter and receiver types, allowing users to select the appropriate transceiver for each link to provide the required optical reach over multimode or single-mode fiber. The creation of QSFP was to meet the market's demand for higher density, high-speed pluggable solutions. The transmission rate for this 4-channel pluggable interface is 40Gbps.
I、The difference between QSFP and SFP is mainly in data rates. As shown in the table

	QSFP	SFP
Data rates	4 x 1 Gbit/s QSFP 4 x 10 Gbit/s QSFP+ 4 x 14 Gbit/s QSFP+ (QSFP14) 4 x 28 Gbit/s QSFP+ (QSFP28)	1 and 2.5 Gbit/s SFP 10 Gbit/s SFP+ 25 Gbit/s SFP28

QSFP vs. SFP
00001. QSFP stands for 4 channels of SFP traffic.
00002. Allowing data rates is difference.
 
 

"II. What are SFP and QSFP?

2.1 What is SFP?
SFP (Small Form-factor Pluggables) can be simply understood as an upgraded version of GBIC. The SFP module (half the size of a GBIC module) allows for over double the port quantity in the same panel space.

2.2 What is QSFP?
QSFP stands for Quad Small Form-factor Pluggable. The four-channel SFP interface (QSFP) was born to meet the market's demand for higher-density, high-speed pluggable solutions. This 4-channel pluggable interface reaches a transmission rate of 40Gbps. Many mature key technologies in XFP have been applied to this design. QSFP can serve as a fiber-optic solution, with both speed and density superior to the 4-channel CX4 interface. Because it supports data transmission for four channels at a speed of 10Gbps per channel in the same port volume as XFP, the density of QSFP can reach four times that of XFP products and three times that of SFP+ products. The four-channel and higher-density QSFP interface has been adopted by the InfiniBand standard.

III. There are five types of SFP:

(1) 1 Gbit/s SFP
(1) Gbit/s SFP also offers the following subtypes:
1 Gbit/s multimode fiber, LC connector, with black or beige pull-out rod
1.25 Gbit/s multimode fiber, LC connector, pull rod color not standardized
1 to 2.5 Gbit/s single-mode fiber, LC connector, with blue pull-out rod
1 Gbit/s for copper twisted pair cable, 8P8C (RJ-45) connector

(2) 10 Gbit/s SFP+ Enhanced Small Form-factor Pluggable (SFP+) is an enhanced version of SFP, supporting data rates up to 16 Gbit/s.
(3) 25 Gbps SFP28 SFP28 is a 25 Gbit/s interface that evolved from the 100 Gigabit Ethernet interface, usually implemented with 4 x 25 Gbit/s data channels.
(4) cSFP Compact Small Form-factor Pluggable (cSFP) is a version of SFP with the same mechanical form factor, allowing two independent bidirectional channels per port.
(5) Small Form-factor Pluggable Double Density (SFP-DD) Multi-Source Agreement is a new standard that doubles port density.  

IV. QSFP also has five types:

(1) 4 Gbps QSFP The original QSFP document specifies four channels, carrying Gigabit Ethernet, 4GFC (Fibre Channel), or DDR InfiniBand.
(2) 40 Gbit/s QSFP+ QSFP+ is an evolution of QSFP, supporting four 10 Gbit/sec channels, carrying 10 Gigabit Ethernet, 10GFC Fibre Channel, or QDR InfiniBand. These 4 channels can also be combined into a single 40 Gigabit Ethernet link.
(3) 50 Gbit/s QSFP14 The QSFP14 standard is designed to carry FDR InfiniBand, SAS-3, or 16G Fibre Channel.
(4) 100 Gbit/s QSFP28 The QSFP28 standard is designed to carry 100 Gigabit Ethernet, EDR InfiniBand, or 32G Fibre Channel. For simplicity, this transceiver type is sometimes referred to as 'QSFP100' or '100G QSFP.'
(5) 200 Gbit/s QSFP56 QSFP56 is designed to carry 200 Gigabit Ethernet, HDR InfiniBand, or 64G Fibre Channel.
  40G QSFP+ can be directly connected with four 10G SFP+ using an 8-core MTP to LC fiber patch cable. Four LC duplex connectors are needed, and this direct connection method is typically suitable for short-distance transmission. For example: Cisco QSFP-4SFP10G-CU5M, QSFP+, 4SFP+ 10G, high-speed direct attach cable.