Things We Should Know Before Migrating to Base-8 System

Since the introduction of Base-12 connectivity in the mid 1990s, the 12-fiber MTP/MPO connector and Base-12 connectivity have served the data center for about twenty years. It has helped a lot in achieving high-density and manageable cabling. Recently, many documents and posts are discussing about a new technology—Base-8. Its appearance is regarded as the evident need of future networks. Even though most of the words are promoting the overwhelming advantages of Base-8 system, we should still consider the defects and merits of these two systems based on some facts before taking the next step by ourselves. This post is a discussion on this topic.

Facts of Base-12 and Base-8

In this part, the design features of Base-12 and Base-8 systems will be introduced. And their dominant advantages are going to be discussed too.

Design Features

Base-12 connectivity makes use of links based on groups of 12, with 12-fiber connectors such as the MTP. In Base-12 connectivity, for example, trunk cables have fiber counts that are divisible by number 12, like 24-fiber trunk cable, 48-fiber trunk cable and all the way up to 144 fibers. However, in a Base-8 system, we don’t have 12-fiber trunk cable, instead we have 8-fiber trunk cable, 16-fiber trunk cable, 32-fiber trunk cable and so on. All trunk cables are based on increments of 8 fibers.

Base-12 and Base-8 trunk cables are visually different on connector design. A Base-12 trunk cable generally has unpinned (female) connectors on both ends and demands the use of pinned breakout modules. In the new emerging Base-8 system, a trunk cable is designed with pinned (male) connectors, as a result, it should be connected to unpinned components.

pinned & unpinned connectors
Figure: Unpinned Connector and Pinned Connector
Comparison

Compared with Base-8, Base-12 obviously has the benefit of higher connector fiber density. Thus a larger number of fibers can be installed more quickly when using Base-12 connectivity. And it is very easy to be deployed into all-ready existing Base-12 architecture. As the networks are migrating to 40G and 100G data speeds, Base-8 connectivity has some advantages that cannot be denied. For some 40G and 100G applications, including SR4 (40G and 100G over parallel MMF) and PSM4 (100G over parallel SMF) supported eight-fiber transceivers, and SAN switch Base-8/Base-16 port arrangements, Base-8 connectivity is a more cost-effective choice. In these applications, Base-8 enables full fiber utilization for eight-fiber transceiver systems. But Base-8 connectivity is not optimized for all situations, including duplex protocols like 25G and 100G (duplex SMF).

Correct Co-existence of Base-8 and Base-12

If we are going to deploy Base-8 devices in our existing network, it is possible to have Base-12 and Base-8 connectivity at the same time as long as we do not mix them in the same link. On one hand, it is not wise to use conversion module between Base-12 and Base-8 devices, because the added cost and increased insertion loss will surpass the benefits it can brought. As mentioned before, the two systems are not interchangeable since they usually have different connector configurations and have unequal attachment requirements. Therefore, special care should be given when managing the data canter physical layer infrastructure, to ensure that the Base-12 and Base-8 components are used separately.

Conclusion

When a new technology comes out as a new option for us, we need to decide whether to change or not. In terms of the discussion on Base-12 and Base-8 systems, after listening to voices from different sides, the key factors are still determined by own specific needs. If we decided to move to the new technology, the following question is how to realize the best migration. Having comprehensive understanding of the solutions and products vendors supply will never be a bad choice.

Which Fiber Loopback Should I Use for My Transceiver?

In telecommunication, fiber loopback is a hardware designed to provide a media of return patch for a fiber optic signal, which is typically used for fiber optic testing or network restorations. When we need to know whether our fiber optic transceiver is working perfectly, we can use a fiber loopback cable as an economic way to check and ensure it. Basically, the loopback aids in debugging the physical connection problem of the transceiver by directly routing the laser signal from the transmitter port back to the receiver port. Since fiber optic transceivers have different interface types and connect different types of cables, it is not that simple to choose a right loopback for our transceiver. This post will be a guide on how to choose a right loopback cable for specific transceiver module.

Fiber Loopback Types and Configurations

Before deciding which loopback cable to use, we should firstly know the structure and classification of fiber loopback cable. Generally, a fiber loopback is a simplex fiber optic cable terminated with two connectors on each end, forming a loop. Some vendors provide improved structure with a black enclosure to protect the optical cable. This designing is more compact in size and stronger in use. Based on the fiber type used, there is single-mode loopback and multimode loopback, available for different polishing types. According to the optical connector type of the loopback, fiber loopback cables can be divided to LC, SC, FC, ST, MTP/MPO, E2000, etc. In testing fiber optic transceiver modules, the most commonly used are LC, SC and MTP/MPO loopback cables.

lc&sc loopback cable
Figure 1: LC & SC Loopback Cable

The LC and SC loopbacks are made with simplex fiber cable and common connectors; it’s not difficult to understand their configurations. As for the MTP/MPO loopback, it is mainly used for testing parallel optics, such as 40G and 100G transceivers. Its configuration varies since the fiber count is not always the same in different applications.

8 Fibers MTP/MPO Loopback Cable Configuration

In a 8 fibers MTP/MPO loopback, eight fibers are aligned on two sides of the connector, leaving the central four channels empty. And the fibers adopt a straight configuration of 1-12, 2-11, 5-8, 6-7. The polarity channel alignment is illustrated in the following figure.

8 Fibers Loopback Polarity Channel Alignment
Figure 2: 8 Fibers Loopback Polarity Channel Alignment
12 Fibers MTP/MPO Loopback Cable Configuration

The only difference between the 12-fiber MTP loopback and the 8-fiber loopback is that the central four channels are not empty. Its alignment is 1-12, 2-11, 3-10, 4-9, 5-8, 6-7.

12 Fibers Loopback Polarity Channel Alignment
Figure 3: 12 Fibers Loopback Polarity Channel Alignment
24 Fibers MTP/MPO Loopback Cable Configuration

The 24 fibers MTP loopback also adopts type 1 polarity. Its alignment design is shown below.

24 Fibers Loopback Polarity Channel Alignment
Figure 4: 24 Fibers Loopback Polarity Channel Alignment
Which to Choose for a Specific Transceiver?

Considering the common features of the transceiver and the loopback, we should think about the connector type, polish type, and cable type when selecting a loopback for the transceiver. The selection guide for some mostly used transceiver modules is summarized in the following tables.

Table 1: Loopback choices for 10G SFP+ transceivers

Model Interface type Cable Type Suited Loopback
10GBASE-USR LC Duplex (PC) MMF

LC/UPC Duplex Multimode Fiber Loopback

10GBASE-SR LC Duplex (UPC) MMF
10GBASE-LR LC Duplex (UPC) MMF
10GBASE-ER LC Duplex (UPC) SMF

LC/UPC Duplex Single-mode Fiber Loopback

10GBASE-ZR LC Duplex (PC) SMF

Table 2: Loopback choices for 40G QSFP+ transceivers

Model Interface type Cable Type Suited Loopback
40GBASE-CSR4 MTP/MPO (UPC) MMF

8/12 Fibers MTP/UPC Multimode Fiber Loopback

40GBASE-SR4 MTP/MPO (UPC) MMF
40GBASE-PLRL4 MTP/MPO (APC) SMF

8/12 Fibers MTP/APC Single-mode Fiber Loopback

40GBASE-PLR4 MTP/MPO (APC) SMF
40GBASE-LR4 LC Duplex (PC) SMF

LC/UPC Duplex Single-mode Fiber Loopback

40GBASE-LR4L LC Duplex (UPC) SMF
40GBASE-ER4 LC Duplex (UPC) SMF
40GBASE-LX4 LC Duplex (UPC) MMF/SMF

LC/UPC Duplex Multimode/Single-mode Fiber Loopback

Table 3: Loopback choices for 100G QSFP28 transceivers

Model Interface type Cable Type Suited Loopback
100GBASE-SR4 MTP/MPO (UPC) MMF

8/12 Fibers MTP/UPC Multimode Fiber Loopback

100GBASE-PSM4 MTP/MPO (APC) SMF

8/12 Fibers MTP/APC Single-mode Fiber Loopback

100GBASE-LR4 LC Duplex (UPC) SMF

LC/UPC Duplex Single-mode Fiber Loopback

Table 4: Loopback choices for CFP transceivers

Model Interface type Cable Type Suited Loopback
40GBASE-SR4 CFP MPO/MTP (UPC) MMF

8/12 Fibers MTP/UPC Multimode Fiber Loopback

40GBASE-LR4 CFP SC Duplex (UPC) SMF

SC/UPC Duplex Single-mode Fiber Loopback

40GBASE-FR CFP SC Duplex (UPC) SMF
100GBASE-LR4 CFP SC Duplex(PC/UPC) SMF
100GBASE-ER4 CFP SC Duplex(PC/UPC) SMF
100GBASE-SR4 CFP MPO/MTP (UPC) MMF

24 Fibers MTP/UPC Multimode Fiber Loopback

Conclusion

This post discusses specific fiber loopback choices for some most commonly used fiber optic transceivers. For other transceiver modules that are not mentioned in this post, we can also know how to choose a suitable loopback for it by getting details about its interface type, physical contact and cable type.

Multiple Applications of 1U Detachable Horizontal Cable Management Panel

Good cable management is essential to keep the fiber cables in acceptable condition and ensuring transmission performance with high-density cabling. A 1U detachable horizontal panel is an amazing part in cable management due to its multiple choices for application. This article will introduce the structure of a 1U detachable cable management panel and its diverse applications in network installation.

Structure of the 1U Detachable Cable Management Panel

This 1U detachable horizontal cable management panel consists of four parts that are held together by screws and can be removed by tools. They are illustrated in the following figure, including horizontal laser bar, horizontal laser panel, D-rings and 1U patch panel.

Structure of the 1U Detachable Cable Management Panel

Multiple Application Choices of the Detachable Cable Management Panel

This 1U detachable horizontal cable management panel can be used to manage cables for different active or passive network devices because they can be assembled randomly to meet your needs. Here are four application examples of this detachable cable management panel.

It is a good choice for holding different types of adapter panels. As a whole, this detachable cable management panel can be used with LC adapter panel. Here it is used with four fiber adapter panels with 12 LC duplex single-mode adapters. Besides, taking off part 4, it can also be used with a 12/24-port adapter in 1U patch panel form.

1U adapter panel is used with LC adapter panel

Combining part 2, 3 and 4 mentioned above, it can be used with MTP/MPO adapter panel. Here it is used for four 8 MTP adapter panel. It should be noted that for each MTP/MPO adapter, 8-fiber MTP/MPO connector is also suited to be linked with 12-fiber MTP/MPO connector when only 8 fibers are used in the 12-fiber MTP/MPO (such as in 40G network).

1U detachable panel is used with MTP adapter panel

By using only part 2 and part 3, cable management for a 1U rack mount fiber enclosure is perfectly achieved.

1U detachable panel is used with enclosure

The combination in the last example can also be used to manage cables coming from 1U WDM Mux/Demux or switch. In the following figure, on the top this detachable panel is used with a 18 channels CWDM Mux/Demux and at the bottom it is used with a switch.

1U detachable panel is used with CWDM Mux/Demux and switch

Conclusion

From the application examples presented above, we can see that this 1U detachable horizontal cable management panel is very capable in different cabling situations. You may notice that cable ties are also used to help organize the cables placing inside the D-rings. If you interested in this multifunctional assembly, you can find it on our site (FS.COM). You can also find many other helpful cable management assemblies for managing efficiently high-density structured cabling in your data centers and telecommunication rooms.

The following table displays some details of several cable management devices provided by us They are all in stock at Seattle warehouse and are available for same-day shipping.

Picture Description
cable management-1 1U Detachable Horizontal Panel with D-ring & Lacing Bar
cable management-2 1U Plastic Single-side Horizontal Cable Management Panel with Finger Duct
cable management-3 24 Ports UTP Cat5e 110 Punch Down 1U 19” Fast Ethernet Patch Panel
cable management-4 1U Metal Horizontal Lacer Panel with D-rings

MTP Specifications and Deployment for 40GBASE-PLRL4 QSFP+

Commonly, QSFP+ transceiver designed with LC interface works with single-mode fiber for long distance application, while QSFP+ transceiver with MTP/MPO interface is used over multimode fiber for short distance transmission. For instance, 40GBASE-ER4 QSFP+ is designed with LC duplex interface, and it supports maximum transmission length of 40 km over single-mode LC duplex fiber; 40GBASE-SR4 QSFP+ with MTP/MPO interface supports a transmission distance no more than 150m over multimode fiber. However, in order to meet user’s diverse needs in real applications, some 40G transceivers are designed not following this rule, like 40GBASE-PLRL4 (parallel LR4 Lite). This transceiver is with MTP/MPO interface design but is used over single-mode fiber for long distance transmission. This article will introduce the MTP/MPO specifications for this transceiver and its deployment cases.

40GBASE-PLRL4 transceiver

MTP Specifications for 40GBASE-PLRL4 QSFP+

QSFP-40G-PLRL4 transceiver uses MTP-12 interface to achieve parallel transmission, supporting maximum data links up to 1.4 km. The cable type required for 40GBASE-PLRL4 is an APC (angle polished connector) single-mode MTP-12 cable. The cable is similar to the 40G-SR MTP or MPO, with the only change being the use of single-mode fiber. UPC (ultra polished connector) is another type of connector for MTP-12 cables, but it is not suited for single-mode fiber in market. APC is the only available type for single-mode MTP-12 fiber. The MTP-12 connector plugged into the QSFP-40G-PLRL4 transceiver carries the 40G signal over only 8 of the 12 fibers, remaining four fibers unused, and these four can optionally be not presented in the cable for economic reason. The used 8 fibers are mapped as 4x10G Tx and Rx pairs. In addition, the MTP cables connected to QSFP-40G-PLRL4 transceiver can be either MTP trunk cables or MTP splitter cables.

Deployment of 40GBASE-PLRL4 QSFP+

The QSFP-40G-PLRL4 is optimized to guarantee interoperability with any IEEE 40GBASE-LR4 and 10GBASE-LR. So when the link for 40G network and 10G to 40G migration is less than 1.4 km, it will be very appropriate to use 40GBASE-PLRL4 QSFP+ transceiver with single-mode MTP cables.

In the first case, you can choose a MTP trunk cable together with the 40GBASE-PLRL4 QSFP+ module for direct 40G connection. The following picture shows two 40GBASE-PLRL4 QSFP+ transceivers connected by a single-mode 12-fiber MTP trunk cable.

40GBASE-PLRL4 QSFP+ for 40G connection

In the second case, you can simply use an 8-fiber MTP to 4xLC duplex harness cable with one 40GBASE-PLRL4 QSFP+ and four 10GBASE-LR SFP+ to achieve 10G to 40G.

40GBASE-PLRL4 QSFP+ for 10G to 40G migration

You can see in the above two cases, MTP cable plays an important role and due to the special requirements of 40GBASE-PLRL4 for single-mode MTP APC fiber, it is necessary to choose the right MTP products connected to this 40G QSFP+.

Conclusion

40GBASE-PLRL4 QSFP+ module has special interface design which can be only compatible with single-mode MTP connector. During the deployment of 40GBASE-PLRL4 QSFP+ module, selecting proper MTP assemblies are essential to successfully accomplish the link. FS.COM is a professional fiber optic transceiver vendor and MTP product manufacturer, supplying compatible 40GBASE-PLRL4 QSFP+ transceiver of different brands, such as Cisco, Arista, Brocade, Huawei, etc. Also other customized compatible brands are available for your requirements. MTP cables and assemblies are available for same-day shipping at low prices, including customized 8 fibers MTP/MPO trunk cable. You will be surprised to see how many kinds of network devices FS.COM can offer and you will get more than cost-effective products but also impressive service.

MTP HD Cassette and TAP Cassette Over Standard LGX Cassette

Pre-terminated fiber cabling has become a favorable choice for today’s high speed networks in data centers as this technology enables high bandwidth, high port density, easy management, future data rates migration and security monitoring. And modular system allows for rapid deployment of high density data center infrastructure as well as improved troubleshooting and reconfiguration during moves, adds and changes. MTP cassette is such a modular module. Usually it employs configuration of 12 fibers or 24 fibers, containing MTP adapter, LC/SC adapter, MTP-LC or MTP-SC patch cable etc, of which MTP-LC cassette is more widely used. As an assembly of the high density MTP/MPO pre-terminated fiber devices, it is dominant in high-density data centers for its reliable interface, optimized performance and minimized rack space. There are commonly three types of MTP cassettes available in market, including MTP LGX cassette, MTP HD cassette and MTP TAP cassette. This article will introduce the advantages of MTP HD cassette and MTP TAP cassette over the standard MTP LGX cassette.

FS.COM MTP cassette

MTP HD Cassette Over MTP LGX Cassette

Though the MTP cassette is preferred for its high density, there is still difference in used rack space between MTP LGX cassette and HD cassette. For standard LGX cassette, usually 3pcs of LGX cassette are put inside a 1U19’’ rack, or 12pcs inside a 4U 19’’ rack, as shown in the figure below. However, HD cassette is more optimized for high-density applications than LGX cassette for being more compact in package. 5pcs of HD cassette can be put inside a 1U 19’’ rack. So if the space for a data center is urgent to be saved, MTP HD cassette will be the best selection to help minimize the rack space for the most fiber count.

standard LGX in 1U and 4U fiber enclosures

MTP TAP Cassette Over MTP LGX Cassette

TAP (traffic access point) is usually added in the network for network monitoring. MTP TAP cassette is an effective device for real-time monitoring in high performance network and high density cabling. TAP cassette integrates TAP functionality into cable patching system. A TAP uses a passive fiber optic splitter to create an exact copy of the light signal passing through it. The fiber carrying the signal from a device’s transmit port is connected to the splitter input; the splitter’s live output is connected to the receive port of the downstream device, while a second output carries the copy of the live signal for out-of-band access. A TAP uses two of these splitters, installed on the two fibers supporting both channels of a duplex fiber channel link, to create a complete copy of all traffic between the two devices. And the transmission for the network data will not be affected since there are ports for monitoring and ports for transmission. The MTP TAP cassette can adopt both the package of HD and LGX cassette. The MTP TAP cassette can be easily deployed in network by connecting to the monitoring device and the user device with MTP trunk/breakout cables or LC/SC patch cables. For this hardware tool, TAP cassette is more expensive than the other two cassette types.

Conclusion

This article compares two MTP cassettes with the MTP standard LGX cassette and states the advantages of them. So if space is the primary consideration in high density cabling, MTP HD cassette is a better design choice; if a secure network with high performance is the priority, MTP TAP cassette is recommended to be deployed in the network. For special applications where high density and monitoring are both required, MTP TAP cassette with compact design is the best choice!