How to Select the Right Fiber Patch Cable for 40G QSFP+ Transceiver?

 It is clear that most servers in data center can support Ethernet transmission of 40G and 40G QSFP+ transceivers are considered to be the most economical solution for 40G transmission in data center. However, to make all these devices run normally and effectively, fiber patch cables must be used to connect the fiber optic transceivers which are plugged in Ethernet switches which is shown in the following picture. As the structure of 40G transmission is more complex than ever, the select of patch cords for 40G QSFP+ transceiver becomes more difficult. This article will focus on how to select the proper patch cords for 40G QSFP+ transceivers in details.

Let’s get straight to the point. Numerous things need to be taken into consideration for proper selecting the fiber patch cables for 40G QSFP+ transceivers in practical cabling. However, several factors should always be considered: the cable type of the patch cords, the connector attached on the ends of the patch cords, and the ports of the switches that need to be connected.
For the first factor to be considered is cable type. This is because of the transmission characteristic optical signals of the fiber optic. Optical signals performs different over different wavelength. And optical signals with the same wavelength performs totally different when they run through different types of cables.
A question that people might come across can illustrate the above point well. Can a 40GBASE universal QSFP+ transceiver working on wavelength of 850nm be used with OM1 patch cords? Usually, signals with wavelength of 850nm are transmitted over short distance. Thus selecting a multimode fiber patch cords would be more economical. However, OM1 patch cords, which are ususally suggested for 100Mb/s and 1000Mb/s, cannot support 40G transmission and the quality of the 40G transmission is bad. This is because the transmission distance reduced as the data rate raised. For this case, OM3 and OM4—the optimized multimode fiber optic cables for 40G transmission in short distance are suggested. OM3 can support 40G transmission up to 100 meters and OM4 can support 40G transmission up to 150 meters.
The second aspect should be considered is the connector type that attached on the both ends of the patch cords, which is usually decided by the interface of the 40G transceivers. Usually 40G QSFP+ transceivers for short distance are armed with MPO interface and for long transmission distance up to 10 km usually employ LC interface. However, there are several 40G QSFP+ transceivers do not follow this rule, like 40GBASE-PLR4 and 40GBASE-PLRL4. These transceiver with MPO interface can support transmission over long distance. The biggest characteristics of MPO connector is high density which seems perfectly satisfy the requirement of 40G transmission. However, for this kind of connect, the polarity becomes complex. Thus during the selecting of this types of patch cords. The polarity must be considered. For your reference, here offers another article which is informative about MPO polarity—”Understanding Polarity in MPO System”. The following pictures shows the commonly used 40G transceivers with MPO or LC interfaces.

The third important factor is the switch ports which is closely related to the applications. During the practical cabling, two situations are common. One is 40G QSFP+ to 40G QSFP+ cabling and the other is 40G QSFP+ to 10G SFP+ cabling.
For 40G QSFP+ to 40G QSFP+ cabling: for distance up to 100m, the 40GBASE-SR4 QSFP+ transceiver can be used with OM3 fiber patch cable attached with a MPO one each end. For distance up to 150m, the 40GBASE-SR4 QSFP+ transceiver can be used with OM4 fiber patch cable attached with a MPO one each end. For distance up to 10km, the 40GBASE-LR4 QSFP+ transceiver can be used with single-mode fiber with LC connectors. The picture above shows the transmission of 40GBASE-LR4 QSFP+ transceiver with LC connector over single-mode fiber.
For the 40G QSFP+ to 10G SFP+ cabling, fan out patch cable with MTP connector on one end and four LC duplex connectors on the other end is suggested (as shown in picture below).
In conclusion, three main factors must be considered are fiber optic cable type, fiber optic connector type and the switch port. In practical cabling, more should be considered. These three aspects are far from enough. However, Fiberstore can solve your problems with professional one-stop service including the cost-effective and reliable network designing and 40G products. You can contact sales@fs.com for more details.

评论

发表评论

此博客中的热门博文

What Is VLAN Switch and Why Do We Need It?

图片
VLAN or virtual LAN is a type of LAN that is defined to map workstations based on everything except for geographic location. It develops when the network has increased in size and complexity, and many companies require more access ports or a network design. Basically, it’s a networking technology which allows the network to be segmented logically without geographic restrictions. But how much do you know about VLAN switch? What Is  VLAN Switch? VLAN switch is built on the fiber optic switch  of LAN, which realizes the division and management of logical working group as a software. As defined in IEEE standard 802.1Q, VLAN switch can provide a way to transform one network into multiple broadcast domains. And each broadcast domain is usually matched with IP subnet boundaries, so that each subnet has its own VLAN. Therefore, users can obtain various wired LANs for different purposes that are co-existed physically, which means you don’t need to buy additional hardware or cabling at a la
阅读全文

Differentiate the 3 Technologies: Switch Stacking vs Cascading vs Clustering

图片
When we have more than one switches on hand we often seek to a better way in making use of them and managing them. There are mainly three technologies that we might use when we interconnect or combine several switches together, which are switch stacking, cascading and clustering. For many people that firstly get in touch with these terms, they can’t figure out the differences between them. Some discussions of the switch stacking versus switch clustering and switch stacking versus switch cascading have been put forward, but a comprehensive comparison between them has not been made. So this post is a discussion of switch stacking vs cascading vs clustering. Switch Stacking vs Cascading vs Clustering The comparison of switch stacking, cascading and clustering should be based on knowing the meaning of these technologies. So firstly we will see what switch stacking, cascading and cluster are. What Are Switch Stacking, Cascading and Clustering? Switch stack
阅读全文

Nylon Zip Ties vs Hook-&-Loop (Velcro®) Ties

图片
The confinement system is the last but critical part of the entire cable management systems. Cable tie plays a very important role in this part. However, there are various types of cable ties in the market. Which one is better? Since nylon zip ties and hook-&-loop (Velcro®) ties are most common and controversial. This tutorial will compare these two types of cable ties in details. Overview of Cable Ties Cable ties are cheap and simple components used in cable confinement system. They are usually the last measure to ensure the cable managed in order. Cable ties are available in a variety of sizes and materials for use on different applications with different requirements. In addition, there are various of color options for cable ties. These color codes help users to manage the cabling and achieve easy troubleshooting. The most commonly used formats of cable ties are nylon zip ties and hook-&-loop (Velcro®) ties, as the Figure 1 & 2 shown: Figure 1. Drawing of Nylo
阅读全文