Server Power Cords Applications in Different Cabling Systems

Each power supply has a separate power cord to support its work. Server power cord connecting the servers and PDU (power distribution unit) plays a critical role in this process. Since the power cords standard for connector types and voltage levels varies from country to country. It’s important to choose the most suitable one for network systems. This post intends to give a simple introduction to server power cords and their applications in different systems.

Power Cords Overview

Usually standard power cords or jumper power cords are available for connection to the server. Power cord consists of three necessary parts: plug, cord and receptacle. And there are many different types of power cords used all over the word. The most commonly seen types are the IEC60320 power cord and NEMA power cord. The former one is often used in US. While the latter is usually seen in North America and other countries that use the standards set by the NEMA.

Among these two types of power cords, the most popular one in some vendors like Dell, HP and IBM is the C13 to C14 power cord. And there are many kinds in this two types of power cords. Here is a simple table showing them.

C14-C13 5-15P – C13
14 to 13 power cord NEMA 15p-C13 power cord
C14-C15 5-15P – C15
C14 to C15 power cord 5-15P - C15 power cord
Applications in Different Cabling System
Cabling for Low Density System

It’s relatively easy to install cords for low density systems. Take servers in a tower configuration for an example. It needs to use a country-specific power cord for direct connection to a facility AC feed. However, server availability goals can require providing redundant AC power to the server in the form of a redundant AC bus or a UPS. The following figure shows two servers connected an UPS with a different types of server power cords. Server in picture A uses C13 to C14 power cord, and server in picture B uses NEMA 5-15P to C13 power cord.

server power cord 1

Note: Connection to a local AC outlet requires an optional country-specific power cord for each power supply. Just shown in picture A above.

Cabling for Medium Density System

Medium density system is a little complex than low density system. Therefore different types and other accessories are maybe needed to achieve an effective power connection. Just shown in the following picture, power connections are achieved using modular PDH, extension bars and C13 to C14 power cord assemblies.

server power cord 2

Note: some servers contain hot-pluggable fans accessible by sliding the chassis out on rails. This means the power cords or jumper cables connecting to the servers must have adequate length and slack to allow chassis movement while staying connected and powered up.

Cabling for High Density System

Compared with the application of power cords in the two systems mentioned above, power cords used in high density systems can be short since cable movement is of little. This following figure shows three kinds of methods to connect enclosures to AC power. The first one shown in the upper area of this figure is that the C13 to C14 power cord is used to connect a single-supply server to a vertical mount PDU, which is suitable for lower-density installations. The second shown in the central area of the figure is to use the C13 x4-to-C20 fixed cord extension bars, a method recommended for extreme-density installations using redundant power supplies. The last one shows the use of a C13 x2-to-C20 Y-cable assembly recommended for connecting a server with dual 1200-watt power supplies directly to a PDU core with C19 outlets.

server power cord 2

Note: Considering there are many cables used in high-density systems, color coding power cords are helpful in systems like that.

Conclusion

Power cords serve as an important bridge in the network device power supply system. FS.COM offers several varieties of IEC power cords, NEMA power cords, and jumper cords for server rack equipment in up to 12 colors with many different types and options for your data center power cords, including: IEC C14 to C13, C20 to C19, C14 to C15, etc. Welcome to visit our website www.fs.com for more information.

Interconnect Solutions for Arista QSFP-40G-PLRL4 and SFP-10G-LR

Usually for single-mode fiber optic transceivers, the interface will be designed as LC duplex type. And for these optical modules, it will be easy to achieve structured cabling by using single-mode LC duplex infrastructure. But for 40G QSFP+, some single-mode transceivers do not follow this common rule. For example, 40GBASE-PLRL4 is a single-mode module supporting a transmission distance up to 1 km, but it has to be connected with an MTP/MPO-12 UPC connector. When migrating from 10G to 40G network using 40GBASE-PLRL4 modules, both single-mode LC duplex cable and single-mode MTP/MPO cable will be used. This article will take Arista QSFP-40G-PLRL4 and SFP-10G-LR optical modules as examples to explain several interconnect solutions for them.

Specifications of Arista QSFP-40G-PLRL4 and SFP-10G-LR

Arista 40GBASE-PLRL4 QSFP+ module is designed with a single-mode parallel MTP/MPO port. It can support a maximum link distance of 1 km on single-mode fiber operating at 1310nm wavelength. Arista 10GBASE-LR SFP+ module also has a single-mode port but its interface is LC duplex type. This SFP-10G-LR transceiver supports a long transmission distance up to 10 km over single-mode fiber operating at 1310 nm. Both of them support digital and optical monitoring.

Interconnect Solutions for Arista QSFP-40G-PLRL4 and SFP-10G-LR

In the first solution, a breakout cassette is used to move one 40G signal to four individual 10G signals. A 40G MPO cable is used on the QSFP-40G-PLRL4 side and four LC uniboot cables are connected to four SFP+s. The MTP/MPO equipment we used in this solution and the solutions below are all aligned as polarity B type.

interconnect for single-mode QSFP+ and SFP+ with MPO-12 to LC cassette

Figure 1: interconnect for single-mode QSFP+ and SFP+ with MPO-12 to LC cassette.

The second connection is a very cost-effective solution for three QSFP-40G-PLRL4 to twelve SFP-10G-LR modules. Here the three breakout cables on the left are female MPO to 4xLC 8 fibers harness. Then by using two 6 LC duplex adapter panel, the three groups of 40G signals are divided into two groups that each has six 10G network devices. In this link, no fiber or port is wasted. Besides, it also allows flexible location of the QSFP+ modules, like in different chassis. By using customized bend insensitive single-mode LC duplex fiber patch cable, high performance transmission at longer lengths can be achieved.

 interconnect for single-mode QSFP+ and SFP+ with MPO-8 to LC harness cable

Figure 2: interconnect for single-mode QSFP+ and SFP+ with MPO-8 to LC harness cable.

The next solution illustrated in figure 3 is a bit similar to the previous example in figure 2. It is also for three 40G parallel and twelve 10G duplex single-mode optical transceivers. But it is an application of MTP conversion harness cable and breakout patch panel. Here we used 3×8 strand MTP (female) to 2×12 strand MTP (female) single-mode conversion harness cable to connect the three QSFP+ transceivers to the 96 fibers 12xMTP/MPO-8 (male) to LC single-mode 40G breakout patch panel. Twelve LC uniboot patch cables are connected to the SFP-10G-LR transceivers.

interconnect for single-mode QSFP+ and SFP+ with 2x3 24-fiber MTP conversion harness cable

Figure 3: interconnect for single-mode QSFP+ and SFP+ with 2×3 24-fiber MTP conversion harness cable.

The last interconnect solution is for two single-mode QSFP+ and eight SFP+ modules. Here another type of MTP conversion cable is used. It is a 2×12 strand MTP (female) to 1×24 strand MTP (female) single-mode conversion harness cable. A 24 fibers male MTP-24 to LC UPC duplex single-mode cassette is used to connect the MTP-24 connector and the eight LC duplex connectors. Low loss LC uniboot cables are again used for this high-density cabling.

interconnect for single-mode QSFP+ and SFP+ with 1x2 24-fiber MTP conversion harness cable

Figure 4: interconnect for single-mode QSFP+ and SFP+ with 1×2 24-fiber MTP conversion harness cable.

Conclusion

This post introduced four interconnect solutions for single-mode parallel QSFP-40G-PLRL4 transceiver and single-mode duplex SFP-10G-LR transceiver. In order to meet different requirements, different equipment is deployed in different examples. Hope that these connections can be a guide for your single-mode network and can work well in specific applications.

The Role of OM5 and MTP Fiber in 40GbE and Beyond

In order to meet the overwhelming trend of growing bandwidth, different standards for single-mode and multimode fibers are published, and parallel fiber connector (MTP/MPO) is designed to solve the problem of increasing fiber count. Though the fiber types are changing, the use of the parallel connector seems not to be outdated, not only for present 40G and 100G applications, but also for future 200G and 400G. This post will discuss the issue on a new fiber type and the role of parallel fiber in 40GbE and beyond networks.

Overview on Multimode and Single-mode Fibers

Since the establishment of multimode fiber in the early 1980s, there has been OM1 and OM2, and laser optimized OM3 and OM4 fibers for 10GbE, 40GbE and 100GbE. OM5, the officially designated wideband multimode fiber (WBMMF), is a new fiber medium specified in ANSI/TIA-492AAAE. The channel capacity of multimode fiber has multiplied by using parallel transmission over several fiber strands. In terms of single-mode fiber, there are only OS1 and OS2; and it has been serving for optical communications without much change for a long time. Compared with the constant updates of multimode fiber and considering other factors, some enterprise customers prefer to use single-mode fiber more over the past years and for the foreseeable future. With the coming out of the new OM5 fiber, it seems that multimode fiber might last for a longer time in the future 200G and 400G applications.

The Issue on the Upcoming Fiber Type

The new fiber medium OM5 is presented as the first laser-optimized MMF that specifies a wider range of wavelengths between 840 and 953 nm to support wavelength division multiplexing (WDM) technology (at least four wavelengths). It is also specified to support legacy applications and emerging short wavelength division multiplexing (SWDM) applications. Although OM5 has been anticipated to be “performance compliant and superior to OM4” based on the following parameters, there are still some arguments on the statement that OM5 is a better solution for data centers.

OM4 & OM5 comparison

Figure 1: OM4 and OM5 comparison.

OM5 supporters talk about the problems of present multimode fibers in long-term development. The opinion holds that the future 400GBASE-SR16 which will reuse 100GBASE-SR4 technology specified in IEEE 802.3bs Standard draft, calls for a new 32 fibers 2-row MTP/MPO connector instead of a 12 fibers MTP/MPO connector. It will be hard for current structured cabling that uses MTP-12 to move to MTP-16 requirements.

12f and 32f MTP-MPO connectors

Figure 2: 12f MTP connector (left) and 32f MTP connector (right).

However, the OM5 fiber solution, which can support 4 WDM wavelengths, will enable 4 fiber count reduction in running 40G, 100G and 200G using duplex LC connections. Combined with parallel technology, 400G can also be effectively transmitted over OM5 fibers using only 4 or 8 fibers.

40G, 100G, 200G, and 400G WDM transmission over OM5 fiber

Figure 3: 40G, 100G, 200G, and 400G WDM transmission over OM5 fiber.

On the other side, some people don’t support the idea that OM5 is a good solution for future 400G network. They argue that OM5 isn’t that optimized than current MMF types. The first reason is that for all the current and future multimode IEEE applications including 40GBASE-SR4, 100GBASE-SR4, 200GBASE-SR4, and 400GBASE-SR16, the maximum allowable reach is the same for OM5 as OM4 cabling.

MMF-Standard-Specifications-1

Figure 4: Multimode fiber standard specifications.

MMF-Standard-Specifications-continued

Figure 4 continued.

The second reason is that, even by using SWDM technology, the difference on the reaches for OM4 and OM5 in 40G and 100G is minimal. For 40G-SWDM4, OM4 could support a 400-meter reach and OM5 a 500-meter reach. For 100G-SWDM4, OM4 could support 100 meters and OM5 is only 50 meters more than OM4.

And thirdly, the PAM4 technology can increase the bandwidth of each fiber from 25G to 50-56G, which means we can stick to current 12-fiber and 24-fiber MTP/MPO connectors as cost-effective solutions in the 40G, 100G and beyond applications.

Conclusion

The options for future higher speed transmission are still in discussion, but there is no doubt that no matter we choose to use new OM5 fiber or continue to use single-mode fiber and OM3/OM4 fiber, the “parallel fibers remain essential to support break-out functionality” as stated in WBMMF standardization. It is the fact that parallel fiber solution enables higher density ports via breakout cabling and reduces cost per single-lane channel.

CMR, CMP and LSZH MTP/MPO Cable

Multifiber MTP/MPO cable is a preferable choice for high-density telecom and datacom cabling. For the outer jacket of MTP/MPO cable, there are many terms to describe it, such as CM, LSZH, CMP, CMR, PVC, etc. FS.COM carries several of these technologies. Do you know the differences between them? And what are the characteristics of each type? Most importantly, which one do you need for the task? This post will introduce some major jacket types for MTP/MPO cable and the other acronyms for communication cable ratings.

MTP cabling

Figure 1: MTP/MPO cabling.

CMP

CMP (plenum-rated) MTP/MPO cable complies the IEC (International Electrotechnical Commission) 60332-1 flammability standard. CMP MTP/MPO cable is designed to be used in plenum spaces, where air circulation for heating and air conditioning systems can be facilitated, by providing pathways for either heated/conditioned or return airflows. Typical plenum spaces are between the structural ceiling and the drop ceiling or under a raised floor. CMP rated communication cable is suitable for telephone and computer network exactly for this matter. It is designed to restrict flame propagation no more than five feet, and to limit the amount of smoke emitted during fire. Additionally, CMP MTP/MPO cable is more fire-retardant than LSZH, and as a result, sites are better protected. As an excellent performer cable, it is usually more costly than other cable types.

It has to be noted that some CMP cable made of fluorinated ethylene polymer (FEP) still has shortcomings of potential toxicity. Thus better CMP cable with a non-halogen plenum compound is further produced. For safety reason, no high-voltage equipment is allowed in plenum space because presence of fresh air can greatly increase danger of rapid flame spreading if the equipment catch on fire.

LSZH

The LSZH (low smoke zero halogen, also refers to LSOH or LS0H or LSFH or OHLS) has no exact IEC code equivalent. The LSZH cable is based on the compliance of IEC 60754 and IEC 61034. LSZH MTP/MPO cable is better than other cables in been safer to people during a fire. It has no halogens in its composition and thus does not produce a dangerous gas/acid combination when exposed to flame. LSZH cable reduces the amount of toxic and corrosive gas emitted during inflammation. LSZH MTP/MPO cables are suitable to be used in places that is poorly aired such as aircraft, rail cars or ships, to provide better protection to people and equipment. LSZH MTP/MPO cable is more widely applied type than other materials, both for its secure properties and lower cost than CMP.

Other Types

The cable jackets will be discussed in the following part are not as frequently used for MTP/MPO cable as CMP and LSZH.

CMR (riser-rated) complies IEC 60332-3 standards. CMR cable is constructed to prevent fires from spreading floor to floor in vertical installations. It can be used when cables need to be run between floors through risers or vertical shafts. PVC is most often associated with riser-rated cable, but nor all PVC cable is necessarily riser-rated; FEP is most often associated with CMP. Since the fire requirements for CMR cable is not that strict, CMP cable can always replace CMR cable, but not reversibly.

CM (in-wall rated) cable is a general purpose type, which is used in cases where the fire code does not place any restrictions on cable type. Some examples are home or office environments for CPU to monitor connections.

The figure below generally illustrates the applicable environments for CMP, CMR and CM rated cables.

CMP, CMR, CM cable application

Figure 2: CMP, CMR, CM cable application.

Conclusion

Knowing the relevant details of cable ratings of MTP/MPO will certainly help in selecting the best one for your applications, which is as important as other factors. FS.COM provides high quality plenum and LSZH MTP/MPO trunk cables and MTP breakout cables at affordable prices.

Connectivity Solutions for Parallel to Duplex Optics

Since we have discussed connectivity solutions for two duplex optics or two parallel optics in the last post (see previous post: Connectivity Solutions for Duplex and Parallel Optics), the connectivity solutions for parallel to duplex optics will be discussed in this article, including 8-fiber to 2-fiber, and 20-fiber to 2-fiber.

Parallel to Duplex Direct Connectivity

When directly connecting one 8-fiber transceiver to four duplex transceivers, an 8-fiber MTP to duplex LC harness cable is needed. The harness will have four LC duplex connectors and the fibers will be paired in a specific way, assuring the proper polarity is maintained. This solution is suggested only for short distance within a given row or in the same rack/cabinet.

8-fiber to 2-fiber direct connectivity

Figure 1: 8-fiber to 2-fiber direct connectivity

Parallel to Duplex Interconnect

This is an 8-fiber to 2-fiber interconnect. The solution in figure 2 allows for patching on both ends of the fiber optic link. The devices used in this link are recorded in the table below figure 2.

8-fiber to 2-fiber interconnect

Figure 2: 8-fiber to 2-fiber interconnect

Item Description
1 8 fibers MTP trunk cable (not pinned to pinned)
2 96 fibers MTP adapter panel (8 ports)
3 8 fibers MTP trunk cable (not pinned)
4 MTP-8 to duplex LC breakout module (pinned)
5 LC to LC duplex patch cable (SMF/MMF)

Figure 3 is also an interconnect for 8-fiber parallel QSFP+ to 2-fiber SFP+. This solution is an easy way for migration from 2-fiber to 8-fiber, but it has disadvantage that the flexibility of the SFP+ end is lacked because the SFP+ ports have to be located on the same chassis.

8-fiber to 2-fiber interconnect

Figure 3: 8-fiber to 2-fiber interconnect

Item Description
1 8 fibers MTP trunk cable (not pinned to pinned)
2 96 fibers MTP adapter panel (8 ports)
3 8 fibers MTP trunk cable (not pinned)
4 8 fibers MTP (pinned) to duplex 4 x LC harness cable

Figure 4 shows how to take a 20-fiber CFP and break it out to ten 2-fiber SFP+ transceivers. The breakout modules divide the twenty fibers into three groups, and ten LC duplex cables are used to accomplish the connectivity to SFP+ modules.

20-fiber to 2-fiber interconnect

Figure 4: 20-fiber to 2-fiber interconnect

Item Description
1 1×3 MTP breakout harness cable(24-fiber MTP to three 8-fiber MTP) (not pinned)
2 MTP-8 to duplex LC breakout module (pinned)
3 LC to LC duplex cable (SMF/MMF)
Parallel to Duplex Cross-Connect

There are two cross-connect solutions for 8-fiber parallel to 2-fiber duplex. The main difference for figure 5 and 6 is on the QSFP+ side. The second cross-connect is better for a greater distance between distribution areas where the trunk cables need to be protected from damage in a tray.

8-fiber to 2-fiber cross-connect (1)

Figure 5: 8-fiber to 2-fiber cross-connect (1)

Item Description
1 8 fibers MTP trunk cable (not pinned)
2 MTP-8 to duplex LC breakout module (pinned)
3 LC to LC duplex cable (SMF/MMF)

8-fiber to 2-fiber cross-connect (2)

Figure 6: 8-fiber to 2-fiber cross-connect (2)

Item Description
1 8 fibers MTP trunk cable (not pinned to pinned)
2 96 fibers MTP adapter panel (8 ports)
3 8 fiber MTP trunk cable (not pinned)
4 MTP-8 to duplex LC breakout module (pinned)
5 LC to LC duplex cable (SMF/MMF)
Conclusion

These solutions are simple explanations to duplex and parallel optical links. It seems that the difference between each solution is not that significant in plain drawing, but actually the requirements for components are essential to an efficient fiber optic network infrastructure in different situations. Whether it is a narrow-space data center or a long-haul distribution network that will mostly determine the cabling structure and the products used.