Can QSFP+ Optical Transceiver be plugged on the port of QSFP28 Optical Transceiver?

Talking about the question: whether QSFP+ optical module transceiver can be plugged on the QSFP28 port of the 100G switcher or whether 100G QSFP28 optical module can be utilized on the QSFP+ port. There may be an answer.

An Overview of QSFP28 Optical Transceiver

100G QSFP28 optic fiber module is a hot-pluggable transceiver module designed for 100G data rate. “28” means each lane carries up to 28G data rate. The QSFP28 has 4 electrical lanes that can be used as a 4x10GbE, 4x25GbE, depending on what types of transceivers are used(the main types of QSFP28 optics consist of 100G QSFP28 SR4, 100G QSFP28 LR4, QSFP28 CWDM4 and QSFP28 PSM4, shown as the pic ).

A Brief Introduction to QSFP+ Optical Transceiver

QSFP+(Quad Small Form-factor Pluggable Plus) is the most common 40GbE interface type, and also as a high-density 10GbE interface via QSFP+ breakout cables. It connects a network device (switch, router, media converter or similar device) to a fiber optic or copper cable, supporting data rates of 4×10Gbps and supporting Ethernet, Optic Fibre Channel, Infiniband and SONET/SDH standards with different data rate options. Compared with CFP (C form-factor pluggable) transceiver modules, QSFP+ transceiver modules are more compact and more suitable for port-density application. QSFP+ supports the data rate of 40G, 4 channels for transmitting and 4 channels for receiving, each lane carrying 10G. QSFP+ can break out into 4x10G or 1x40G connection.

Can QSFP+ Optics Be Plugged on the Port of QSFP28?

QSFP28 optical transceiver is similar to QSFP+ in the form factor and size, and 25Gb/s is available in per channel of QSFP28 optics. While 10Gb/s is available in the per channel of QSFP+ optics. Therefore, the port of QSFP28 can be backward compatible with QSFP+ optical transceiver.

A 100G QSFP28 port can generally take either a QSFP+ or QSFP28 optics. If the QSFP28 optics support 25G lanes, then it can operate 4x25G breakout, 2x50G breakout or 1x100G (no breakout). The QSFP+ optic supports 10G lanes, so it can run 4x10GE or 1x40GE. If one uses the QSFP+ transceiver on QSFP28 port, one has to keep it in mind that single-mode/multimode (SR/LR) optical transceivers, and twinax/AOC products are for options.

However, on the contrary, QSFP28 optics cannot be plugged on the QSFP+ port, which is due to that the requirements for the data rate can not be satisfied. There is a rule about mixing optical transceivers with different speed—it also depends on the optics and the ports. Two ports of the optical transceiver module have to match and form factor needs to match as well. Additionally, port speed needs to be equal or greater than the optic used.

Summary

It can be concluded that QSFP+ optical transceiver module can be connected on the QSFP28 ports, but QSFP28 optics cannot transmit 100Gbps on the QSFP+ port.

评论

发表评论

此博客中的热门博文

Differences between cisco GLC-T and cisco GLC-TE

 Cisco GLC-T, GLC-TE and SFP-GE-T optical modules are all Gigabit port optical modules with RJ45 interface and 100m transmission distance. They are cost-saving solutions for Gigabit Ethernet connection in data center, access network and storage area network applications. Therefore, these three types of optical modules are often difficult to distinguish. In fact, the transmission effect of these three optical modules is the same, which optical module can achieve Gigabit transmission, but it is certainly noteworthy that the original Cisco GLC-T and SPF-GE-T optical modules were terminated on June 1, 2017 and replaced by GLC-TE optical module. SFP-GE-T optical module with NEBS 3 ESD function needs to be selected if it is traded directly with the telecommunications company (which requires NEBS).The price of GLC-T and GLC-TE optical modules is low, and they can also meet the needs of Gigabit Ethernet. The Cisco Gigabit optical modules provided by Easy Communications can meet a large number
阅读全文

Cisco 10GBASE SFP+ Modules Data Sheet

 Product overview The Cisco 10GBASE SFP+ modules offer you a wide variety of 10 Gigabit Ethernet connectivity options for data center, enterprise wiring closet, and service provider transport applications. Features and benefits Cisco SFP+ modules offer the following features and benefits. Industry’s smallest 10G form factor for greatest density per chassis Hot-swappable input/output device that plugs into an Ethernet SFP+ port of a Cisco switch (no need to power down if installing or replacing) Supports “pay-as-you-populate” model for investment protection and ease of technology migration Digital optical monitoring capability for strong diagnostic capabilities Optical interoperability with 10GBASE XENPAK, 10GBASE X2, and 10GBASE XFP interfaces on the same link Cisco quality Identification (ID) feature enables a Cisco platform to identify whether the module is certified and tested by Cisco Cisco SFP-10G-SR-S module (S-Class) The Cisco 10GBASE-SR module supports a link length of 26 meter
阅读全文

Why the sfp transceiver not work

 The failure of the sfp optical module is divided into the failure of the transmitter and the failure of the receiver. Through the analysis of the main causes of the phenomenon, the most likely problems are mainly concentrated in the following aspects: The optical port of the  1000base SFP transceiver  is contaminated and damaged Because of the pollution and damage of the optical interface of the module, the loss of the optical link is increased, so that the optical fiber link is unreachable. The main reasons for this phenomenon are the following four points: 1. The optical port of the SFP optical module has been exposed to the environment for a long time, resulting in contamination and contamination of the SFP optical port; 2. The end face of the fiber jumper connected to the  Cisco SFP-10g-sr  optical module has been contaminated, and the SFP optical port provides been contaminated; 3. Improper operation of the end face of the optical connector with pigtails, scratching of the finish
阅读全文