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Category: Copper Networks

10G Stacking Over Cat6a or DAC

10G Stacking Over Cat6a or DAC

We have got benefits from the stacking of 10G SFP+ switches for the past decades, and the 10G SFP+ direct attach cable (DAC) makes the stacking low-cost. But when 10GBASE-T becomes a new port choice on 10G switches, stacking on 10G switches has to meet the issue about whether to choose Cat6a or SFP+ DAC. At first people think that Ethernet cable is cheaper and easier to deploy than SFP+ DAC, but later they realized the issue is not only about the cable cost.

  10G stacking-cat6a or DAC

Comparison of Stacking 10G Over Cat6a and SFP+ DAC

Before going on, it should be noted that this discussion is focused on 10G stackable switches that have both 10GBASE-T ports and SFP+ ports (such as Cisco 550X series switches, Dell 8024).

In terms of the cost, one Cat6a cable costs just one third of a 10G SFP+ DAC of the same length. But cable price is not the only factor that contributes to the total budget in building a network. Let’s see some properties of these two technologies.

Power Consumption
SFP+ DAC Cat6a
Power Consumption Per Port 1-1.5 W 4-6 W
Max. Reach 10 m 100 m

Obviously, SFP+ DAC uses much less power than Cat6a cable. It is important to know that for every watt of power consumed, typically two additional watts are needed for cooling. If there is a lot of ports in the stacking, this power consumption will be significant. So when power consumption matters a lot in your stacking, it will be a huge saving to choose SFP+ DAC instead of Cat6a.

10G cable power consumption
More ports mean more power consumption.
Latency

Also in a case when low latency is strictly required, like in automated financial trading, it is also better to use SFP+ DAC for 10G stacking. Because for the same links and lengths, Cat6a presents higher latency than SFP+ DAC.

automated financial trading low latency
Automated financial trading requires low latency.
Distance

When you have many stacked 10G switches located at different places, i.e. at separate floors or at opposite ends of a hallway, Cat6a can achieve the stacking connection if it is less than 100 m. But typically you’ll be suggested to use fiber link, because the power consumption in long-term could exceed the extra cost for buying 10G fiber optics and cables.

10G stacking distance
The stacking distances affect the cable choice.

As for distances more than 100 m, neither SFP+ DAC nor Cat6a can work. You have to turn to fiber optic patch cable and 10G SFP+ transceiver module.

Conclusion

Considering the total cost and performance of Cat6a and SFP+ DAC for 10G stacking, SFP+ DAC appears to be a better choice in short range. The low power consumption and low latency properties can help accomplish a good stacking, and thus shortening the downtime, improving resiliency, and simplifying administration.

Difference Between Passive and Active Twinax Cable Assembly

Difference Between Passive and Active Twinax Cable Assembly

Optical fiber cabling had gone through rapid development over recent years and maintained its leading role in telecom field. While twinax cable still remained a good way to access the networking industry trends over the last three decades and presented the highest longevity among all media. Twinax cable (see in following Figure) is a type of cable similar to coaxial cable that has two inner conductors instead of one. And owing to its cost efficiency, it is commonly used in short-range high-speed differential signaling applications. Currently there is a twinax cable which comes in either passive or active copper cable. So what is the difference between them? Today’s passage will provide a satisfying solution to you.

Twinax cable

Describing Passive and Active Twinax Cable
A passive twinax cable carries a signal over short lengths (5m or under) of copper with no additional components to boost signal. While an active copper cable contains electrical components in the connectors that boost signal levels. This makes active copper cables a little more expensive than passive copper cables; however, they can connect the Converged Network Adapter (CNA) to a top-of-the-rack switch over longer distances than passive copper cables.

Why Implement Active Over Passive and Vice Versa?
Length and signal strength are always two important factors you should look into when requiring a cable for an application. Typically, we can see passive twinax cables being used between the server and the Top of Rack (ToR) switch. The upside in this configuration is that the passive twinax cabling connection is much cheaper than the cost of an optical link. The downside is that you are limited in distance and there’s also some cable interoperability issue you’ll need to deal with. Passive twinax cables are rated for ranges up to 5m and provide a good working solutions at a great cost.

When the distance between connection points exceeds 5m, it is highly recommended to use active cables to ensure signal is transferred all the way through. The downside is that they are more expensive and use more power. The upside is that you don’t have to worry about distance (up to 300 meters) and, perhaps more importantly, you don’t have to worry about which vendor’s cable you use and the signal is improved and gives peace of mind by creating a trustworthy connection. In regards to active versus passive twinax cables, it depends on what you are connecting together.

QSFP+ Copper Cables—A Cost-effective Application of  Twinax Cable
QSFP+ direct attach copper cable assemblies offer a highly cost-effective way to establish a 40 Gigabit link between QSFP+ ports of QSFP+ switches within racks and across adjacent racks. QSFP+ Copper Cable is an extension of the established interface system SFP+ that is mainly used in short distance. 40G QSFP+ to 4SFP+ copper breakout cable and QSFP to QSFP copper direct attach cable are the two common types of 40G QSFP+ Copper cables.

QSFP to 4SFP+ copper breakout cables are suitable for very short distances and offer a very cost-effective way to connect within racks and across adjacent racks. Take QSFP-4SFP10G-CU1M as an example, this breakout cable connects a 40G QSFP port and four 10G SFP+ ports of Cisco switches and operates at a link length of 1m. While a QSFP+ to QSFP+ passive copper cable consists of a cable assembly that connects directly into two QSFP+ modules, one at each end of the cable. This cable use integrated duplex serial data links for bidirectional communication and is designed for data rates up to 40Gbps. There are various QSFP+ to QSFP+ passive copper cables branded by famous brands, like Cisco, HP, Juniper, Brocade, etc. The following picture shows a Cisco QSFP-H40G-CU3M Compatible QSFP+ to QSFP+ passive copper cable.

Cisco QSFP-H40G-CU3M

Summary
There isn’t a truly visual way to tell the difference between active and passive twinax cables. Therefore when you are requiring a twinax cables, please follow the instructions that I have listed above or you should ask your vendors for expertise suggestion. Fiberstore offers a large variety of SFP+ Twinax cables and QSFP+ cables that are well tested and compatible with major brand. If you have any inquiry of our products, please feel free to contact us.

Considerations of Planning a Pre-terminated Cabling Infrastructure

Considerations of Planning a Pre-terminated Cabling Infrastructure

pre-terminated copper trunkPre-terminated cable assemblies including various trunk cables, patch cords, and plug-and-play cassettes provide a plug-and-play, time-saving and easy-to-deploy solution for links between switches, servers, patch panels and ZDA (Zone Distribution Areas) in a data center. However, compared to field-terminated cabling, pre-terminated cabling need more additional upfront planning and detailed analysis in order to establish the cabling and termination routes and lengths needed. Thus, some key considerations should be remembered when planning a pre-terminated cabling infrastructure.

Architecture & Configuration

Common network architectures include traditional three-tier switch architecture, fabric switch architecture, end-of-row, middle-of-row, and top-of-rack configurations. Understanding what type of architecture and configuration will be deployed in your network will help determine the placement of devices such as switches, routers and servers. In addition, it ultimately impact the cabling termination routes and length needed. It is a very important and basic consideration.

Cabling Media

Cabling media mainly includes copper and fiber. To determine which type should be used is a key part of the planning process. The selection criteria are determined by cost considerations, bandwidth requirement, distance limitations, equipment interfaces, power consumption, pathway space, and overall life-cycle costs. In addition, we should also consider the cabling environment such as the influence of electromagnetic or radio frequency interface (EMI/RFI).

pre-terminated-fiber

Migration & Scalability

A right pre-terminated cabling infrastructure is not only to satisfy today’s requirements but also to meet future-proof upgrade. Knowing the migration strategy and future plans is important for us to choose the right pre-terminated cabling and components with enough scalability. For instance, if we need to migrate from 10GbE to 40/100GbE network, careful consideration should be given to the fiber count, connector type, distances, insertion loss budget, and ease of switching out cassettes or other connectivity components.

Pathways

Pathways contain position, elevations, required separation, and type of pathway system used (e.g. overhead or underfloor) can impact the cable lengths. Thus, considerations such as specific rack heights and clearances, accommodating required separation, selecting the cable support system, etc. should be determined before calculating cable lengths between equipment and patch panels.

Cable Runs

The rack-level detail of the installation is also an important consideration that impacts pre-terminated cable lengths. It is important to order lengths that do not come up short while avoiding too much slack in cabinets and pathways. In addition, bend radius and service loops must be considered. Moreover, proper sequencing is also important to ensure that longer cable trunks are laid into trays first for an overall cleaner installation.

Other Considerations

In addition to the above considerations, there are other important considerations for choosing right pre-terminated cabling, such as cable density and airflow. Cable polarity, color-coding as well as the customer needs and specifications also require proper planning and detailed analysis. If using custom pre-terminated cable assemblies, make sure that the delivery of materials can catch up with your deployment schedule.

Pre-terminated cabling solution helps save much time and even much labour due to its benefits of plug-and-play and easy-to-deploy. But only choosing the right cabling that can satisfy your network demands will get the most out of the investment. The above contents list some key considerations which may give you some guides before planning a pre-terminated cabling infrastructure.

Buyer Guides: FS.COM offers a series of cost-effective fiber and copper pre-terminated cabling solutions which satisfy your today’s and tomorrow network demands. OEM is also available to meet your unique demands. If you are interested in them, you can purchase the most cost-effective products from FS.COM or contact sales@fs.com for details.
Differences Between Phone & Network Cable

Differences Between Phone & Network Cable

When connecting the computer to the network devices like switches and routers, you must use a network cable, namely an Ethernet patch cable. A regular phone cable will not work, even though it looks similar to a network cable. There are some differences between phone cable and network cable, including:

Network cables are usually thicker and rounder than a telephone cable.

rj45-vs-rj11Network cables, including Cat5, Cat5e, Cat6, Cat6a, etc., are twisted pair cables for carrying signals in structured cabling for computer networks such as Ethernet. An Ethernet network cable consists of 8 wires; twisted, and made into 4 pairs, each colour coded by a solid colour with their respective dashed/striped white cables. While phone cables are narrower and flat, and are made up of four wires. Thus, a network cable is wider than a phone cable, resulting in larger bandwidth than phone cable.

Network cables have larger RJ-45 connectors and phone cables usually have smaller RJ-11 connectors.

The connectors terminated with an Ethernet network cable are commonly known as RJ-45 connectors. Phone cables have the similar connectors called RJ-11. “RJ” is short for registered jack. The RJ-45 has eight contacts that accept eight wires, also know as pins. Network cables usually have more pins than phone cables. Thus, RJ-45 connector is larger than an RJ-11 connector. And as a result, the jack for network cables is wider than a phone’s cable.

There are different usages of network cables and phone cables.

Phone cables are generally used for home telephone lines and Digital Subscriber Line (DSL) connections. Ethernet network cables are typically used to interconnect computers and network devices such as hubs, switches and routers. Depending on different connection, there are straight-through network cable and crossover network cable for choice.

cable usages

Ethernet network cables and phone cables look alike, and they both send and receive information. But as mentioned above, they differ in many ways. Are there other differences between them? Let us know in the comments.

Buyer Guides: FS.COM offers a full range of Ethernet network cables including Ethernet network patch cables and bulk cables of Cat5e, Cat6, Cat6a and Cat7. If you have demands on them, you can purchase the most cost-effective cables from FS.COM. View more information in this page or contact sales@fs.com for details.
Copper Cabling Choices for 10G Ethernet

Copper Cabling Choices for 10G Ethernet

Nowadays, though fiber becomes popular with the benefit of delivering the lowest latency, many IT departments still use copper cabling for switch-to-switch or switch-to-server connections in 10G Ethernet (10 GbE). Currently, there are two major copper cabling technologies applied for 10 GbE over copper. What are they?

As the following table shown, one of the 10GbE copper cabling options is the SFP+ Direct Attach Copper Cable (DAC Cable), and the other one is the 10GBASE-T with twisted-pair Ethernet cable. In the following section, they are respectively introduced in details.

Media Copper Cable Distance (max) Averange Latency Standard
SFP+ DAC Twin-ax copper SFP+ Cu 10 m (33 ft) 0.1 μs MSA SFF-8431
10GBASE-T Twin-pair Category 6 RJ45 30 m (98 ft)-50 m(164 ft) >1.5 μs IEEE 802.3an-2006
Twin-pair Category 6A RJ45 100 m (328 ft) >1 μs
Twin-pair Category 1 GG45 100 m (328 ft) >1 μs

 

SFP+ DAC Is Convenient for Short Runs

SFP+ is the form factor for 10GbE optical transceivers. 10G SFP+ DAC cable is designed with SFP+ connectors on two ends of a twin-ax copper cable. Because of its low latency, small form factor, and reasonable cost, it has become the preferred and convenient 10GbE copper cabling option for servers and storage devices in a rack, usually within 10 meters (33 ft). 10G SFP+ DAC can help simplify rack cabling and termination. For instance, in a ToR (Top of Rack) architecture, each server and network storage device can be directly connected to the ToR switch without the need for intermediate patch panels. More over, 10G SFP+ DAC is flexible enough for vertical cabling management within the rack architecture. The only cabling outside the rack is the ToR switch uplink connection to the aggregation layer, making moving racks easy.

10G Ethernet copper cabling option: 10G SFP+ DAC

10GBASE-T With CAT 6A Cable Is Perfect for Long-Term Plan

10GBASE-T was released by IEEE 802.3an in 2006 which specifies 10Gbps data transmission over four-pair copper cabling. 10 GbE over CAT 6A cable and CAT 7 cable that use RJ45 connectors can reach up to 100 meters. Among them, CAT 6A is currently the preferred cable option for future-proofing cabling installations and widely used in 10GbE copper cabling. In addition, when using CAT 6A in 10 GbE systems, choosing the right cable type, namely unshielded or shielded (e.g. UTP or F/UTP) is also necessary. In general applications, the UTP cabling is commonly used. But for long-term consideration and noisy environment, the F/UTP may be better.

10G Ethernet copper cabling option: 10GBASE-T CAT 6A

Conclusion

10G Ethernet over copper still plays an important role in the data center switch/server interconnection. Current copper cabling choices for 10G Ethernet include SFP+ DAC and 10GBASE-T with Ethernet cables. Each of them has its own advantage. The SFP+ DAC is convenient for short runs while the 10GBASE-T solution is perfect for long-term plan in a longer distance. Only the right one is the best. So, how do you plan your copper cabling for 10 GbE?