Tag Archives: 40G

Guide to Multimode Fiber Cabling in 40/100G Migration

Nowadays one and 10 Gbqs data rates are not adequate to meet the continued requirement for expansion and scalability in the data center, thus technology evolves and standards are completed to define higher data rates such as 40/100G Ethernet. In the meanwhile the cabling infrastructures installed today must provide scalability to accommodate the need for more bandwidth in support of future applications. OM3 and OM4 multimode cabling solutions have been proven to be a cost-effective solution for 40G data center. Today’s article will make you familiarize with this new Gigabit Ethernet and OM3/OM4 cabling to help you smoothly upgrade to 40G Ethernet.

Multimode Fibers in Data Center

Multimode fiber is more popular in data centers than singlemode fiber. Many people may know the reason—budget. Because the price of multimode fiber is typically much lower than singlemode fiber. Additionally, multimode fibers utilizes the low cost 850nm optical transceiver for both serial and parallel transmission. While singlemode fiber uses the expensive 1310nm and 1550nm transceiver and duplex fiber wavelength division multiplexing (WDM) serial transmission. Therefore, most data center designers would choose multimode fiber for 40/100G transmission.

OM3 and OM4 cable

There are four common types of multimode fibers available in the market—OM1, OM2, OM3 and OM4. Recently OM3 and OM4 cables are gradually taking place of OM1 and OM2 multimode cable. OM3 and OM4 are laser-optimized multimode fibers with 50/125 core, which are designed to accommodate faster networks such as 10, 40 and 100 Gbps. Compared with OM1 (62.5/125 core) and OM2 (50/125 core), OM3 and OM4 can support high data rate and longer distance. This is why OM3 and OM4 is more popular in data center.

The Ratification of IEEE 802.3ba

The Institute of Electrical and Electronics Engineers (IEEE) 802.3ba 40G/100G Ethernet standard was ratified in June 2010. According to this standard, it includes detailed guidance for 40/100G transmission with multimode and singlemode fibers. But the standard does not have guidance for Category-based unshielded twisted-pair or shielded twisted-pair copper cable.

OM3 and OM4 are the only multimode fibers included in 40/100G standard. Because multimode fiber uses parallel-optics transmission instead of serial transmission due to the 850-nm vertical-cavity surface-emitting laser (VCSEL) modulation limits at the time the guidance was developed. Compared to traditional serial transmission, parallel-optics transmission uses a parallel optical interface where data is simultaneously transmitted and received over multiple fibers. Table 2 shows the IEEE standards for 40 and 100 GbE.

IEEE standards for 40 and 100 GbE

The 40G and 100G Ethernet interfaces are 4x10G channels on four fibers per direction, and 10x10G channels on 10 fibers per direction, respectively. For 40GBASE-SR4 transceivers, it utilizes multimode fiber for a link length of 100m over OM3 and 150m over OM4. QSFP-40G-SR4 is Cisco 40GBASE-SR4 QSFP+ that can both operate over OM3 and OM4 cables to achieve 40G connectivity just as FTL410QE2C.

OM3 or OM4?

As noted before, OM3 and OM4 can meet the requirement for 40G migration cabling performance, that’s why they are being widely utilized in 40/100G migration. But OM3 and OM4, which is better for your infrastructure? There is no exact answer to this question as numerous factors can affect the choice. The working environment and the total costs are always the main factors to be considered when selecting OM3 or OM4 multimode cable.


OM3 is fully compatible with OM4. They use the same optical connector and termination of connector. The main difference between them is in the construction of fiber cable that makes OM4 cable has better attenuation and can operate higher bandwidth at a longer distance than OM3. On the other hand, the cost for OM4 fiber is higher than OM3. As 90 percent of all data centers have their runs under 100 meters, choosing OM3 comes down to a costing issue. However, in the long term, as the demand increases, the cost will come down. OM4 will become the most viable product in the near future.


No matter choosing OM3 or OM4 for your infrastructure, 40G migration is in the corner. OM3 and OM4 multimode cable featured by the high performance and low cost are the perfect solution for 40/100G migration. Fiberstore is committed to provide the best-service and high-quality products to customers. Our comprehensive range of products in OM3 and OM4 offer customers the ability to create the optimal network. For more information, you are welcome to contact us.

Introduction to 25G and 40G Ethernet Network

When you look at the evolution of networking and the data that drives it, there is no surprise that Ethernet has been and will continue to be the most widely used network interface. Consumers and network designers wish to smoothly migrate to higher network speed—100G/400G without compromising quality. Ethernet speed upgrade path was clearly defined as from 10G,40G to 100G. But recently a new migrate path (10G-25G-100G) was gradually accepted by subscribers. For those who need to migrate their network to adopt to the big data age, choose 25G or 40G Ethernet, that is the question! This article provides the pros and cons of 25G and 40G Ethernet network. You will get your own answer at the end of it.

25G or 40G

Here Comes 25 Gigabit Ethernet
25 Gigabit Ethernet has passed the first hurdle in the IEEE standards body with a successful Call for Interest (CFI) in July, 2014. It is a proposed standard for Ethernet connectivity that will benefit cloud and enterprise data center environments. 25 GbE leverages technology defined for 100 Gigabit Ethernet implemented as four 25 Gbit/s lanes (IEEE 802.3bj) running on four fibers or copper pairs. Telecom giants like Google, Microsoft, Arista, and Mellanox are pushing the development of a 25 Gigabit Ethernet standard for top-of-tack server networking. Relevant transceiver modules and optical cables are developed to support this technology.

40G Ethernet Network
The IEEE P802.3ba 40G and 100G Ethernet Task Force was formed to develop a 40 Gigabit Ethernet and 100 Gigabit Ethernet draft standard. At the physical layer, 40G Ethernet is essentially 4×10G lanes. Standards-based 40G Ethernet switches and routers are starting to show up in enterprise networks, following ratification of the IEEE 802.3ba specification in mid-2010. QSFP+ modules and 40G DAC cables are introduced to back 40G networking, which are warmly welcomed by network designers. For example, QSFPP-4X10GE-LR (see in Figure 2) is compatible Juniper QSFP+ transceiver. It can be used in a 4×10G modules with 10GBASE-LR interfaces.

Juniper QSFPP-4X10GE-LR

25 Gigabit or 40 Gigabit Ethernet for Your Server
The most obvious feature of 25 Gigabit is described in two words—single lane. The phrase refers to the electrical signaling on the chip that would power an Ethernet port, while the design of 40 GbE was based on 10 GbE. Originally, 100 GbE had a similar heritage, with its initial design in 2010 using 10 lanes of 10 Gbps. This is the first generation of 100G transport links. As standards bodies sought to improve the efficiency of 100 GbE in the coming years, its second generation consists of four lanes of 25 Gbit/s Ethernet on four fiber or copper pairs. This will be disruptive to the 10G and 40G infrastructure.

In addition, the proposed 25 GbE standard reduces the number of lanes on the chip makes it less expensive to produce and less power-hungry. It also simplifies the process with just minor changes for forward error correction and lane alignment when compared to 40 GbE. To sum up, getting 25 GbE performance for the same price of 10G combined with reduced operating costs, which makes itself a compelling proposal for migration.

On the other hand, driven by cloud computing, mobile broad-band and IPTV for higher user bandwidth, demand for 40G transport links is growing quickly. 40G links has been deployed for more than 5 years. Compared to 25GbE, it has a longer history. And a good news is that advances in semiconductor technology and innovative designs are reducing the cost of 40G systems. High-speed serial links, flexible interfaces, integrated packet, lower power and less silicon real estate are all helping telecom manufacturers deliver cost-effective solution to upgrade from 10G to 40G.

The 40GbE specification defines a wide range of port types and has been ratified by IEEE. 40G optical equipment are all compatible with the existing 10G devices. Take 40G-QSFP-4SFP-C-0101 (see in Figure 3) as an example, it is the compatible Brocade QSFP+ to 4SFP+ Passive Breakout Copper Cable, which offer a cost-effective way to establish a 40G link between QSFP port and SFP+ within racks and across adjacent racks. However, 25GbE transceiver modules like QSFP28 and SFP28 will not be compatible with the existing QSFP+ and SFP+ cable assemblies. Which will cause trouble to users. Many experts believe that if people agree to add 40GbE instead of endlessly debating will lead to faster standards completion.

Brocade 40G-QSFP-4SFP-C-0101

Right Move at the Right Time
Planning for migration to higher-speed Ethernet can feel daunting as telecom experts hold different opinions towards the future of 25G and 40G. Some believe that the dominant next-generation server connection speed is going to be 25G, but some confirm that 40G between switches is expected to remain and will not be affected by this development. Just remember to make the right move at the right time. Fiberstore is working on providing cost competitive longer reach option for mainstream customers. We are very glad to offer our expertise in choosing the physical infrastructure that best meets your needs.