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NAS vs SAN: What’s the Difference?

In the era of information technology, data has become the most critical asset for companies. Without access to their data, companies may not be able to provide their customers with desired services. Thus how to effectively store, access, protect and manage critical data is a new challenge facing IT departments. Direct attached storage (DAS), network attached storage (NAS) and storage area network (SAN) are three main technologies for storage networking. Among them, NAS and SAN are similar in using internet technology to ensure users can access and manage their storage data easily. But they are in fact two different storage technologies. This post will focus on NAS vs SAN.

What Are Network Attached Storage and Storage Area Network?

Network attached storage is a file level storage system served as a local area network (LAN) node. It is usually referred to as a single storage device connected to network, allowing clients or associated devices in the LAN to share file-based data through a standard Ethernet connection.

Network attached storage

Unlike network attached storage, storage area network provides block-level network access to storage. It often consists of hosts, switches, storage elements, and storage devices that are interconnected using a variety of technologies, topologies, and protocols.

storage area network

NAS vs SAN: What’s the Difference?

As the name implies, a network attached storage consists just of storage device while a storage area network is a network. The followings are some other differences between them:

NAS vs SAN

1. NAS vs SAN Connections

The network attached storage system can be connected directly to the network using an Ethernet cable into an Ethernet switch. Almost any device that can connect to the LAN (or is interconnected to the LAN through a WAN) can connect to a network attached storage and share files with the use of NFS, CIFS or HTTP protocol.

In contrast, devices in storage area network system are connected together using a network fabric, such as iSCSI or Fibre Channel. And only server class devices with SCSI Fibre Channel in a virtual computing environment can be connected to the storage area network.

2. NAS vs SAN Data Identify

As mentioned above, network attached storage is a file level storage system. So it identifies data by file name and byte offsets, transfers file data or file meta-data and handles security, user authentication, file locking.

Storage area network stores data in a block level. It addresses data by disk block number and transfers raw disk blocks. In this case, storage area network has lower latency and higher performance than network attached storage.

3. NAS vs SAN Backups and Mirrors

Backups and mirrors of network attached storage are done on files, not blocks, to save bandwidth and time. And the snapshot can be tiny compared to its source volume.

Backups and mirrors of storage area network require a block by block copy, even if blocks are empty. A mirror machine must be equal to or greater in capacity compared to the source volume.

NAS vs SAN: Which One to Choose?

Network attached storage and storage area network are two popular solutions for networking storage. Which on to choose is largely depend on your actual requirements. With much simpler design, network attached storage is far less expensive than storage area network. And it is ideal for those who looking for an easily implemented storage solution. While storage area network is a high-performing and complex system, suitable for companies looking for top-of-the-line storage performance and reliability.

Hyperconverged Infrastructure Basics

Hyperconverged infrastructure has been talked a lot in recent years and its adoption is skyrocketing in data centers. However, many people are still confused by this term. This post will introduce it in details.

What’s Hyperconverged Infrastructure

Hyperconverged infrastructure is often named HCI. It is introduced in 2012 to describe a fully software-defined IT infrastructure that virtualizes all the elements of conventional hardware-defined systems. In other words, the networking and storage tasks in the hyperconverged infrastructure are implemented virtually through software rather than physically in hardware. Generally, hyperconverged infrastructure is at least composed of virtualized computing (a Hypervisor), a virtualized SAN (software-defined storage) and virtualized networking (Software-defined networking). It can be utilized as a way to pool together resources so as to maximize the interoperability of on-premises infrastructure.

Hyperconverged Infrastructure

Hyperconverged Infrastructure VS Converged Infrastructure

Hyperconverged infrastructure and converged infrastructure are two alternative solutions to replace the traditional IT infrastructure. This part will tell the differences between them to help you choose one over another for your network deployment.

Hyperconverged Infrastructure VS Converged Infrastructure

Hyperconverged VS Converged Infrastructure Components

Converged infrastructure defines compute, storage, networking and server virtualization—which are the four core components in a data center—as one dense building block. Hyperconverged infrastructure is born from converged infrastructure and the idea of the software-defined data center (SDDC). Besides the data center’s four core components, hyperconverged infrastructure integrates more components such as backup software, snapshot capabilities, data deduplication, inline compression, WAN optimization and so on.

Hyperconverged VS Converged Infrastructure Principle

Hyperconverged infrastructure is a software defined approach. It means the infrastructure operations are logically separated from the physical hardware, and all components in a hyperconverged infrastructure have to stay together to function correctly. While converged infrastructure is a hardware-focused, building-block approach. Each component in a converged infrastructure is discrete and can be used for its intended purpose. For example, the server can be separated and used as a server, just as the storage can be separated and used as functional storage.

Hyperconverged VS Converged Infrastructure Principle

Hyperconverged VS Converged Infrastructure Cost

Converged infrastructure allows IT to use a single vendor for end-to-end support for all core components instead of the traditional approach where IT might buy storage from one vendor, network from another and compute from another. It also offers a smaller footprint and less cabling, which can reduce the cost of installation and maintenance.

Hyperconverged infrastructure allows IT to build, scale and protect your IT infrastructure more affordably and effectively. For example, a 10GbE Access Layer Switch (8*10/100/1000Base-T+8*1GE SFP Combo+12*10GE SFP+) specially for hyperconverged infrastructure only costs US$ 1,699. And the software-defined intelligence reduces operational management, providing automated provisioning of compute and storage capacity for dynamic workloads.

Conclusion

It is reported that hyperconverged infrastructure will represent over 35 percent of total integrated system market revenue by 2019. This makes it one of the fastest-growing and most valuable technology segments in the industry today. The upfront costs of hyperconverged infrastructure may be a little high now, but in the long term it can pay off.

Which Tight Buffered Fiber Distribution Cable Fits Your Application?

Optical fibers with fiber counts ranging from 2 to 144 counts or more are usually coated together inside a single strand of fiber optic cable for better protection and cabling. Multi-fiber optic cables are usually required to pass a lot of distribution points. And each individual optical fiber should connect only one specific optical interface via splicing or terminating by connectors. Thus, fiber optic cables used for distribution should be durable and easy to be terminated. Tight buffered fiber distribution cables, which meet these demands, are widely used in today’s indoor and outdoor applications, like data center and FTTH projects. This post will introduce tight buffered fiber distribution cables.

tight buffered fiber cable

The Beauty of 900um Tight Buffered Fibers

Most of tight buffered fiber distribution cables are designed with 900um tight buffered fibers. This is decided by its applications. As the above mentioned, the distribution cable should be durable and easy to be terminated. The following picture shows the difference between 250um bare fiber and 900um tight buffered fiber. They are alike, but the tight buffered fiber has an additional buffer layer. Compared with bare fibers, 900um tight buffered fibers can provide better protection for the fiber cores. 900um tight buffered fibers are easy to be stripped for splicing and termination. In addition, tight buffered fiber cables are usually small in package and flexible during cabling. These are the main reasons why a lot of fiber optic distribution cables use tight buffered design.

250um vs 950um

Choose Tight Buffered Distribution Fiber Cables According to Applications

900nm tight buffered distribution fiber cables also come in a variety of types. Tight buffered distribution fiber cables used for different environments and applications might have different fiber types, outer jackets and cable structures. The following will introduce several tight buffered distribution fiber cables for your reference.

unitized distribution fiber cable
Indoor Tight Buffered Distribution Fiber Cable

Tight buffered distribution fiber cables used for indoor applications are usually used for intra building backbones and routing between telecommunication rooms. Large tight buffered fiber cable with fiber counts more than 36 fibers generally has “sub-unit” (unitized) design (shown in the above). While smaller tight buffered distribution cables, with fiber counts of 6, 12 or 24, usually have “single-jacket” (non-unitized) designs, which are more flexible in cabling and have much smaller packages and cost advantages. The lower count tight buffered distribution fiber cables with color coded 12 fibers and 24 fibers are very popular. The following picture shows a 24-fiber indoor tight buffered distribution fiber cable with single-jacket design.

24-fiber tight buffered fiber cable

During practical use, these 6, 12 or 24-fiber indoor tight buffered distribution fiber cables can be spliced with other fibers or be terminated with fiber optic connectors. And they can be made into multi-fiber optic pigtails or fiber patch cable after terminated with fiber optic connector on one end or two end. The color coded fibers can also ease fiber cabling.

Indoor/Outdoor Armored Tight Buffered Distribtight buffered fiber terminationution Fiber Cable

Although tight buffered distribution fiber cables are usually used for indoor applications, there is still a place for them in outdoor applications after added with a layer of metal armored tube inside the cable. Armored fiber cables are durable, rodent-proof, water proof and can be directly buried underground during installation, which saves a lot of time and money.

Armored tight buffered distribution fiber cable

Here we strongly recommend a low fiber count armored tight buffered distribution fiber cable which can be used for both indoor and outdoor applications (show in the above picture). This low fiber count armored tight buffered cable has a single-jacket design with a steel armored tape inside the cable. It can be used for both backbone cabling and horizontal cabling in indoor environments. And it can also be used for direct buried applications and aerial application in outdoor environments.

FS.COM Same Day Shipping Tight Buffered Distribution Fiber Cables Solution

During the purchasing of fiber optic cables, one of the most important thing is the shipment of fiber cables. Many bulk fiber cables are transmitted via shipping, which might take a long time. Now FS.COM customers in the USA can enjoy same day shipping for tight buffered distribution fiber cables for both indoor and outdoor applications. Details are shown in the following table. Kindly contact sales@fs.com for more details, if you are interested.

Part No. Description
31909 12 Fibers OM3 Plenum, FRP Strength Member, Non-unitized, Tight-Buffered Distribution Indoor Fiber Optical Cable GJPFJV
31922 12 Fibers OM4 Plenum, FRP Strength Member, Non-unitized, Tight-Buffered Distribution Indoor Fiber Optical Cable GJPFJV
31866 24 Fibers OM4 Riser, FRP Strength Member, Non-unitized, Tight-Buffered Distribution Indoor Fiber Optical Cable GJPFJV
51308 24 Fibers OS2, LSZH, Single-Armored Double-Jacket, Tight-Buffered Distribution Waterproof Indoor/Outdoor Cable GJFZY53

Source: http://www.fs.com/blog/tight-buffered-fiber-distribution-cables-for-indoor-and-outdoor-use.html

100G QSFP28 Fiber Optic Modules and Standards

The developing of 100G fiber optic transceiver has experienced a lot of challenges, thus various types of 100G fiber optic transceivers are being invented. Many 100G modules appeared on the market for a while and disappeared soon. Now it seems that 100G QSFP28 module will win the competition. It has the same cabling structure as 40G QSFP+ module and high density feature, which allows network upgrade to 100G with lower cost and less time. This post will introduce several commonly used 100G QSFP28 modules and standards.

100G QSFP28

QSFP28 module uses four lanes for 100G optical signal transmitting like 40G QSFP+. However, each lane of QSFP28 can transmit 25G optical signal. To fit the various requirements in practical applications, IEEE and MSA standards that support different transmission distances and fiber types are being published.

100Gbase-SR4 QSFP28

100Gbase-SR4 is a standard published by IEEE. 100Gbase SR4 QSFP28 module uses eight multimode fibers for 100G dual-way transmission over 850nm. It can support a transmission distance up to 70m over OM3 and 100m OM4 with a MTP interface. 12-fiber MTP OM3/OM4 trunk cables are suggested to be used with QSFP-100G-SR4 modules. 100Gbase-SR4 QSFP28 is the most popular QSFP28 module according to research.

100Gbase-LR4 QSFP28

100Gbase-LR4 is another 100G standards published by IEEE. It focuses on longer transmission distance over single-mode fiber. 100Gbase-LR4 QSFP28 has a duplex LC interface and uses WDM technologies to achieve 100G dual-way transmission over four different wavelengths around 1310nm. It can support distances up to 10km.

Although IEEE has defined two 100G standards separately for short and long distances, the requirements of various applications cannot be fully satisfied. For instances, the 100G-QSFP-LR4 module can support 10km, which is too much for a lot of single-mode applications. It would be uneconomical to buy a 10km module for just 1km or 2km application. MSA has published two 100G standards — 100Gbase-PSM4 and 100Gbase-CWDM4, which can help to decrease the cost of 100G deployment.

100Gbase-PSM4 QSFP28

100Gbase-PSM4 QSFP28 module has a MTP interface working on wavelength of 1310nm for 100G transmission over single-mode fibers. It can support transmission distance up to 500 meters. 100Gbase-PSM4 QSFP28 module is much cheaper than 100Gbase-LR4 QSFP28 module. And 500 meter’s transmission distance can cover a wide range of applications.

100Gbase-CWDM4 QSFP2

For longer transmission distance, 100Gbase-CWDM4 QSFP28 is suggested, which supports a distance up to 2km over single-mode fiber optic cable. 100Gbase-CWDM4 standard is published by MSA, which is a more cost-effective solution for a wide range of applications compared with 100Gbase-LR4. This module uses CWDM technologies to transmit the 100G optical signal via a duplex LC interface over wavelengths near 1310nm.

100G QSFP28 DAC

100G QSFP28 family also includes a series of direct attach cables. There are mainly two types of QSFP28 DAC, which are QSFP28 to QSFP28 DAC and QSFP28 to SFP28 DAC. These QSFP28 DACs are cost-effective solution for 100G transmission less than 5 meters.

100G QSFP28 Module Interface Fiber Type Distance Standards
100Gbase-SR4 QSFP28 MTP Multimode 70m (OM3); 100m (OM4) IEEE
100Gbase-LR4 QSFP28 LC Duplex Single-mode 10km IEEE
100Gbase-PSM4 QSFP28 MTP Single-mode 500km MSA
100Gbase-CWDM4 QSFP28 LC Duplex Single-mode 2km MSA
Conclusion

There are many ways to transmit to 100G network. 100G QSFP28 modules are the suggested methods. Both IEEE and MSA published standards for 100G QSFP28. For short distance transmission over multimode, 100Gbase-SR4 QSFP28 module is suggested. For single-mode applications, 100Gbase-PSM4 supporting 500m, 100Gbase-CWDM4 supporting 2km and 100Gbase-LR4 supporting 10km are available. The above table shows the basic information of these modules for your reference.

Difference Between 100G-QSFP-PSM4, 100G-QSFP-SR4 and 100G-QSFP-LR4

QSFP28 fiber optic transceiver is becoming the preferred solution for 100G network. It has the same outside looking as the 40G QSFP+ transceiver. But it has a 4*25G electrical interfaces which can transmit optical signals up to 100G. The part numbers of the QSFP28 transceivers are usually market as 100G-QSFP-xx. Now there is a wide selection of 100G QSFP28 modules for 100G Ethernet link, including fiber optic transceiver and direct attached cable. Different part numbers of 100G modules are making customers confused. This post will introduce the differences between the three 100G QSFP28 modules: 100G-QSFP-PSM4, 100G-QSFP-SR4 and 100G-QSFP-LR4.

100G-QSFP-PSM4

Transmission Mode

It is known that QSFP28 modules generally use four lanes to transmit 100G with each lane supporting 25G. Thus, the transmission method is just like 40G QSFP+ transceiver. 100G QSFP28 SR4, LR4 and PSM4 all use the 4*25 transmission mode. However, both the QSFP28 SR4 and QSFP28 PSM4 use a 12-fiber MTP interface which achieves dual-way 100G transmission over 8 fibers at the same time. QSFP28 LR4 uses a LC duplex fiber optic interface for 100G transmission on two directions at the same time. QSFP28 LR4 transmit optical signals over four different wavelengths around 1310nm with each wavelength carrying 25G optical signal. The wavelength ranges of the four lanes are as following:

  • 1294.53nm-1296.59nm
  • 1299.02nm-1301.09nm
  • 1303.54nm-1305.63nm
  • 1308.09nm-1310.19nm
Transmission Media and Distances

The three modules can support different transmission distances. 100G-SR4 QSFP28 module works over wavelength of 850nm and is used with 12-fiber MTP OM3 or OM4 multimode fiber cables for short transmission distances up to 100m. 100G-LR4 QSFP28 module is suggested to be used with single-mode fiber. It works over 1310nm wavelengths and can transmit 100G signals up to 2km. 100G-PSM4 QSFP28 is also used with 12-fiber MTP fiber cables but the fiber type is single-mode and the transmission distance is up to 500m.

100G-QSFP-SR4

Cabling Structure

The transmission mode of the fiber optic transceiver plays an important role during fiber cabling. 100G-QSFP-SR4 and 100G-QSFP-LR4 are invented for short distance transmission and long distance transmission separately. However, the have different cabling structure. The former requires a multi-fiber cabling structure based on 12-fiber MMF MTP interfaces. While 100G-QSFP-LR4 just required the traditional two-fiber SMF cabling structure. In this case, the conversion between multimode fiber to single-mode fiber would be complex as they used totally different cabling structure. Thus, 100G-QSFP-PSM4 is invented which runs over single-mode fiber, but uses the same cabling structure as 100G-QSFP-SR4. With 100G-QSFP-PSM4, the conversion between multimode and single-mode would save more without changing the existing fiber cabling structure.

100G QSFP28 Transceiver Data Rate Interface Fiber Type Transmission
Distance
Wavelengths Cabling Structure
100G-QSFP-SR4 4*25G MTP MMF 70m (OM3);
100m (OM4)
850nm 12-Fiber MTP
100G-QSFP-LR4 4*25G LC SMF 2km 1310nm LC Duplex
100G-QSFP-PSM4 4*25G MTP SMF 500m 1310nm 12-Fiber MTP
Conclusion

The above table listed the basic information of the three modules for your referent. 100G-QSFP-SR4 are suitable for short distance transmission over OM3 or OM4 fiber using 12-MTP fiber cabling system. 100G-QSFP-PSM4 also has a 12-fiber MTP interface but it can support a transmission distance up to 500m over SMF. 100G-QSFP-LR4 is suitable for long transmission distance up to 2km over two single-mode fibers. If you are interested in more 100G QSFP28 modules, kindly click the following page: 100G Transceiver.

Related Article: 40G vs 100G: Which One Is Worth the Investment?