White Box Switch: to Be or Not to Be

Current Situation

White box switch refers to the ability to use “generic”, white box switching and routing hardware in the forwarding plane of a software-defined network (SDN). So that consumer can purchase a generic Ethernet switch without a network operating system (NOS), and install an operating system of their choice. However, white box switch hasn’t been widely accepted and recognized currently. The reasons are as followed: 1. No matter in a data center or enterprise, switch accounts for a very low share in network construction, far below the server, storage, and bandwidth. But it takes up a very important spot in an enterprise, and any problem of it would result in widespread influence. 2. In terms of customer technicians, few people are knowledgeable about network. So when they have problems with network equipment, they are prone to turn to vendor service. While unfortunately, white box switch manufacturers are not professional enough, especially those manufacturers having separated software and hardware, which means white box manufacturers can’t take on projects like branded manufacturers. 3. White box manufacturers have little proficiency. They don’t have complete product lines, and they don’t make core equipment, let alone functionally complex provider equipment (PE).

white box switch

Production Mode

Generally, there are four major components that make up a network switch, namely silicon, box, network OS and drivers, and applications. White box switching is the idea that the silicon & box can be bought as one thing, and the network OS and applications as other things. This idea is opposite to the traditional norm of network switch acquisition. Through the separation of software and hardware, customers can obtain different support levels for hardware and software. Having a software platform that is independent of hardware also allows support engineers to debug it easily and provide relevant output to the networking team.

Advantages

Although status quo of white box switch is not so satisfactory, it won’t block and cloud its prospect of development since it still has a lot of advantages overweighing its disadvantages.

1. Cost

To be honest, most vertically integrated switching & routing platforms are loaded with features the most of consumers will never use. Furthermore, many of the features that consumers want to use come at a high price. So they often have to pay extra expenses for these features. However, the overall cost of white box switch is lower than those branded equipment, because it removed some features that consumers rarely used and brand premium as well.

2. Quality & Simplification

Despite this price advantage, some consumers would regard white box as cheap inferior goods, which turns out a misunderstanding. Because the companies making hardware are professional OEM factories. Their quality of switches is as good as branded switches. Even the brands of hardware are their OEM. That is to say, white box is on par with brand-name systems because they are actually the same hardware. Apart from the quality, white box switch does not involve complicated function, and they only make function sets needed by target consumers. For example, they are less likely to involve MPLS VPN, ISSU Etc. Instead, they focus on relatively simple and controllable data center, especially SDN switch. It simplifies software and makes it understood to most users.

3. Features & Capabilities

White boxes typically are used as a top-of-rack switch or as part of an SDN deployment. They support industry standards such as OpenFlow. Besides, they are highly programmable and work with orchestration tools such as Ansible, Chef and Puppet. Also, white box switches are characterized by strong telemetry capabilities and openness so that network administrators can get whatever information they need for whatever purpose. In fact, in this area, it’s fair to say white boxes are often superior to traditional layer 2/3 switches.

Prospect of White Box Switch

White box switch puts new ground rules in the market, and lowers the cost of acquisition, while at the same time allows consumers to pick and choose the features and functions they are willing to pay for. As the white box switching and NOS market begin to broaden, I believe what the market will see is a broad variety of applications that consumers can choose to add to their newly flexible networks. White box switch is not merely about choosing a hardware manufacturer or NOS provider. The path white box switch ultimately takes us down to is choice of applications running on those switches. That’s a whole different market. That’s a whole different way to think about networking.

25G Vs. 40G Ethernet: Who Is the Winner?

In recent years, the fast growth of data centers leads to increase in global data traffic, which give rise to the need for faster data transmission over a network. 25G Ethernet is the product of that condition. 25G Ethernet is regarded as an incremental update from 10G Ethernet, and it supports 100G Ethernet with single lane at 25Gbps. Due to the booming of 25G, some industry experts claimed that 40G Ethernet is dead, which is biased in some degree. Then 25G vs. 40G Ethernet, which is even better?

Advantages and Disadvantages of 25G and 40G Ethernet
Advantages of 25G Ethernet

Different from 40G and 100G, 25G is a single-lane variant for 25Gbps operation, and that allows a breakout of 100G, which fit the most popular form factors. Based on existing module form factors, such as SFP28 and QSFP28, 25G operations allow for a breakout connection that is configurable as either 25G per lane or the full 100G without changing the port on front of switches, bring more flexibility in the rack and front-panel connections. In addition, with the 25G Ethernet, network operators are no longer forced to use a 40G QSFP port to go from one individual device to another to achieve 100G throughput. The final advantage of 25G is that it can use existing optical plants (depending on what was installed) and increase the bandwidth by 2.5x without changing the physical infrastructure.

25g ethernet sfp28

Disadvantages of 25G Ethernet

As 25G Ethernet is just rising, the interoperability becomes an important factor to ensure wide market adoption and to offer higher speeds for future applications. Besides, compared with 10G 40G and 100G, there aren’t many products of 25G, which limit the development of 25G networks.

Advantages of 40G Ethernet

40G Ethernet is an Ethernet standard developed by the IEEE 802.3ba Task Force to support sending Ethernet frames at 40 gigabits per second. It also addresses physical layer specifications for communication across back planes, copper cabling, multimode fiber optic cable, and single mode fiber. And 40G Ethernet technology is more mature compared with 25G. In the market, there are various types of products for 40G applications, especially the MPO trunk cable assemblies, cassettes, and QSFP 40G optical modules, which offers the required bandwidth for different applications.

40G solution

Disadvantages of 40G Ethernet

At present, 40G is popular in data centers and no drawbacks found. If we have to say one, the utilization of fibers may be one. As we all know, 12-fiber cabling solution is common in 40G networks. But there are four fibers unused, resulting in fiber waste.

Comparison Between 25G and 40G Ethernet in Network
Application

At present, 25G is mainly used for switch-to-server applications. While 40G is for switch-to-switch applications. In other words, no one is using 25G for switch-to-switch links right now. Even the industry giant like Cisco doesn’t offer 25G optical transceiver. But with the fast development of 25G Ethernet, 25G for switch-to-switch application maybe come into reality in the near future.

Switches Selection

Switches are important when comparing 25G and 40G Ethernet. Most switches are currently sold, like Cisco 93180YC-EX, Arista 7060CX-32S support both 10G and 25G, and the price is not higher than older 10G products with full backward compatibility. For example, each SFP28 port supports 1G, 10G or 25G, and each QSFP28 port supports 10G, 25G, 40G, 50G or 100G.

Cabling Options

Cabling options determine how far the two types of Ethernet go. It’s a big mistake to ignore cabling. In the market, there are several types of cabling options, and there are some big swings in price. Here is a simple comparison.

25g ethernet vs 40g ethernet

Summary

From the comparison above, we can draw a conclusion that 25G Ethernet can be used for data centers, but it doesn’t mean 40G is dead. Even though 25G Ethernet seems to have a brilliant future, under present conditions, 40G is a safe choice due to its mature market adoption. Perhaps in a few years, 25G connectivity will be a cheaper alternative.

Network Virtualization and Challenges in SDN/NFV Implementation

Software defined networking (SDN) and network functions virtualization (NFV) are two closely related technologies that are both toward network virtualization and automation. The occurrence of these two technologies are mainly driven by the requirements for robust data management systems and access to bandwidth by servers located at different sites and connected over long distances through public and private clouds. SDN and NFV have some similarities but they are different in many aspects. In addition, though SDN and NFV are highly promoted as next-generation dominants in recent years, there are still many challenges in successfully deploying them. This post will give some basic knowledge about SDN and NFV, and the challenges faced in implementing SDN and NFV.

Understand SDN and NFV

Although SDN and NFV are both network virtualization technologies, they’re really not dependent on each other. And it is not always necessary to involve them in the same network. The infrastructures of SDN and NFV will be explained in the following text, and the major differences between them will be displayed.

What Is SDN?

The function of SDN is somewhat hinted by its name. With SDN, the users are able to manage and control the entire network through software that makes networks centrally programmable. It achieves this by separating the system that decides where traffic is sent (the control plane) from the underlying system that pushes packets of data to specific destinations (the data plane). As known to network administrators and value added resellers (VARs), SDN is built on switches that can be programmed through an SDN controller based on an industry standard controller like OpenFlow.

What Is NFV?

Network function virtualization is similar to traditional server virtualization mechanisms but clearly focuses on networking services. Within NFV, they’re virtualized network functions. It means NFV separates network functions from routers, firewalls, load balancers and other dedicated hardware devices and allows network services to be hosted on virtual machines. Virtual machines have a manager, which allows multiple operating systems to share a single hardware processor.

Differences Between SDN and NFV

Both SDN and NFV rely on software that operates on commodity servers and switches, but both technologies operate at different levels of the network. They are not dependent and you could perfectly have just an NFV platform operating a piece of your environment without the inclusion of full-developed SDN or only SDN. The following figure shows a use case of SDN and NFV.

SDN fabric with NFV

The differences between SDN and NFV can be summarized from five aspects. They are presented in the table below.

SDN NFV
Basics SDN separates control and data and centralizes control and programmability of the network. NFV transfers network functions from dedicated appliances to generic servers.
Areas of Operation SDN operates in a campus, data center and/or cloud environment. NFV targets the service provider network.
Initial Application Target SDN software targets cloud orchestration and networking. NFV software targets routers, firewalls, gateways, WAN (wide area network), CDN (content delivery network), accelerators and SLA (service level agreement) assurance.
Protocols OpenFlow. No protocols, yet.
Supporting Organization Open Networking Foundation (ONF). ETSI NFV working group.

 

Challenges in SDN/NFV Implementation

Though SDN and NFV are promising technologies, there are still many roadblocks in their deployments. Complete standards and proven examples are still needed for wider implementation of SDN/NFV.

Security is one of the biggest concerns in implementing SDN. While centralized control and virtualization of network topology are powerful assets that SDN allows, they also create new security vulnerabilities that must be addressed. The positive side of implementing SDN is that the user is able to make uniform security policies across the whole system. But naturally, the negative side is that, if the SDN controller is successfully hacked, the attacker would have complete control of the system.

Another major challenge is the scalability of SDN systems, in the view of the virtualization that comes with the SDN systems (via NFV). It is a fact that the continuous growth of network data consumption makes scalability a challenge for any network system. If integrated properly, SDN can improve the scalability in a given data center or network. But there are scalability concerns raised by the SDN architecture. Since it is a single item, the centralized SDN controller is not necessarily scalable for larger networks. This also presents a single point of failure in the network, which would be dangerous if the controller or an uplink device fails. There are potential solutions to this problem, but these are still in development.

As for NFV implementation, there are challenges for NFV independent software vendors (ISVs). The first challenge is to develop an innovative, virtualized product that meets the reliability and scalability requirements of the telecom industry. In addition to technical challenges, ISVs also have to develop a concise value proposition to convince the large telcos why they should adopt a new, unproven product into their highly complex network operations.

Conclusion

To sum up, it is no doubt that SDN and NFV can bring many benefits to network administrators by accomplishing virtualization and automation of the systems. And it also cannot be denied that there are still many improvements needed to be made for SDN and NFV deployments. Knowing the pros and cons of them can help in correctly facing these technologies and avoid blind following up or complete refusal to new products. FS.COM has announced new 10/40/100GbE open networking switches for data centers and enterprise networks, which support SDN/NFV. Also high performance 40G and 100G DAC and optical transceivers are provided at competitive prices. For more details about SDN switches, please visit www.fs.com or e-mail to sales@fs.com.

Connectivity Solutions for Duplex and Parallel Optics

In optical communication, duplex and parallel optical links are two of the most commonly deployed cabling structures. This post will discuss some specific connectivity solutions using 2-fiber duplex and 8-fiber/20-fiber parallel fiber optic modules.

Duplex and Parallel Optical Links

A duplex link is accomplished by using two fibers. The most commonly used connector is the duplex LC. The TIA standard defines two types of duplex fiber patch cables terminated with duplex LC connector to complete an end-to-end fiber duplex connection: A-to-A patch cable (a cross version) and A-to-B patch cable (a straight version). In this article the LC to LC duplex cables we use are all A-to-B patch cables. It means the optical signal will be transmitted on B connector and received on A connector.

two types of duplex-patch-cable

Figure 1: two types of fiber patch cables

A parallel link is accomplished by combining two or more channels. Parallel optical links can be achieved by using eight fibers (4 fibers for Tx and 4 fibers for Rx), twenty fibers (10 fibers for Tx and 10 fibers for Rx) or twenty-four fibers (12 fibers for Tx and 12 fibers for Rx). To accomplish an 8-fiber optical link, the standard cabling is a 12-fiber trunk with an MTP connector (12-fiber connector). It follows the Type B polarity scheme. The connector type and the alignment of the fibers is shown in figure 2.

8-fiber parllel system

Figure 2: parallel fiber (8-fiber) optic transmission

To accomplish a 20-fiber parallel optical link, a parallel 24-fiber MTP connector is used. Its fiber alignment and connector type is shown in figure 3.

20-fiber parallel system

Figure 3: parallel fiber (20-fiber) optic transmission
Duplex Fiber Optic Transmission Links (2-fiber to 2-fiber)

We will discuss the items required to connect two duplex transceivers in this part. These 2-fiber duplex protocols include but not limited to: 10GBASE-SR, 10GBASE-LR, 10GBASE-ER, 40GBASE-BiDi, 40GBASE-LR4, 40GBASE-LRL4, 40GBASE-UNIV, 40GBASE-FR, 100GBASE-LR4, 100GBASE-ER4, 100GBASE-CWDM4, 100GBASE-BiDi, 1GFC, 2GFC, 4GFC, 8GFC, 16GFC, 32GFC.

Duplex Direct Connectivity

When directly connecting two duplex SFP+ transceivers, an A-to-B type patch cable is required. This type of direct connectivity is suggested only to be used within a given row of racks/cabinets. Figure 4 shows two SFP+s connected by one LC to LC duplex patch cable.

2-fiber to 2-fiber direct connectivity Figure 4: 2-fiber to 2-fiber direct connectivity

Duplex Interconnect

The following figure is an interconnect for two duplex transceivers. An 8-fiber MTP trunk cable is deployed with 8-fiber MTP-LC breakout modules connected to the end of the trunk. It should be noted that the polarity has to be maintained during the transmission. And pinned connectors should be deployed with unpinned devices. Structured cabling allows for easier moves, adds, and changes (MACs). Figure 5 illustrates this solution.

2-fiber to 2-fiber interconnect (1)

Figure 5: 2-fiber to 2-fiber interconnect (1)

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

Figure 6 is also an interconnect solution for SFP+ transceivers, but on the right side an 8-fiber MTP to 4 x LC harness cable and an MTP adapter panel are used instead. This solution works best when connectivity is required for high port count switch.

2-fiber to 2-fiber interconnect (2)

Figure 6: 2-fiber to 2-fiber interconnect (2)

Item Description
1 LC to LC duplex cable (SMF/MMF)
2 MTP-8 to duplex LC breakout module (pinned)
3 8 fibers MTP trunk cable (not pinned)
4 96 fibers MTP adapter panel (8 port)
5 8 fibers MTP (not pinned) to duplex 4 x LC harness cable
Duplex Cross-Connect

This solution is a duplex cross-connect. It will allow all patching to be made at the main distribution area (MDA) with maximum flexibility for port-to-port connection. Figure 7 illustrates the cross-connect solution for duplex connectivity.

2-fiber to 2-fiber cross-connect

Figure 7: 2-fiber to 2-fiber cross-connect

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

We will discuss items required to connect two parallel (8-fiber or 20-fiber) transceivers in this part. These protocols include but not limited to: 40GBASE-SR4, 40GBASE-xSR4/cSR4/eSR4, 40GBASE-PLR4, 40GBASE-PSM4, 100GBASE-SR4, 100GBASE-eSR4, 100GBASE-PSM4, 100GBASE-SR10.

Parallel Direct Connectivity (8-fiber or 20-fiber)

When directly connecting two QSFP+ or QSFP 28 transceivers, an 8-fiber MTP trunk cable is needed. For directly connecting two CFP transceivers, a 24-fiber MTP trunk cable is needed.

8-fiber to 8-fiber direct connectivity

Figure 8: 8-fiber to 8-fiber direct connectivity
Parallel Interconnect (8/20-fiber)

Figure 9 shows an interconnect solution for two CFP modules (20-fiber). To break-out the CFPs to transmit the signal across an 8-fiber infrastructure, a 1 x 3 breakout harness (24-fiber MTP to three 8-fiber MTP) is required. To achieve an interconnect for two 8-fiber optics, we can replace the breakout harness by an 8-fiber MTP (pinned) trunk and the 24-fiber MTP trunk by an MTP (not pinned) trunk.

20-fiber to 20-fiber interconnect

Figure 9: 20-fiber to 20-fiber interconnect

Item Description
1 1×3 MTP breakout harness cable (24-fiber MTP to three 8-fiber MTP) (pinned)
2 96 fibers MTP adapter panel (8 ports)
3 24 fibers MTP trunk cable, three 8-fiber legs (not pinned)
Conclusion

This post gives brief introduction to the meaning of duplex and parallel optical link and presents some connectivity solutions for two duplex optics or two parallel optics. The corresponding items used in each solution are listed too. The transmission distance and working environment should be taken into account when applying each cabling solution. The parallel to duplex connectivity solutions will be discussed in the next post.

Functions of ONT and OLT in GPON Network

Gigabit passive optical network (GPON) is a point-to-multipoint access mechanism providing end users with the ability to consolidate multiple services onto a single fiber transport network. To realize this technology, many devices are used to support the network, such as optical splitter, ONT, OLT, etc. In this article, we will mainly discuss the functions of ONT and OLT in GPON network.

GPON

Functions of ONT

Optical network terminal (ONT) is an optical modem that connects to the termination point with an optical cable. It is used at end user’s premise to connect to the PON network on one side and interface with the user on the other side. Data received from the customer end is sent, aggregated and optimized by the ONT to the upstream OLT. ONT is also known as optical network unit (ONU). ONT is an ITU-T term, while ONU is an IEEE term. They both refer to the user side equipment in GPON network. A small difference between them might be the application locations. ONU can work in different temperature and weather conditions.

ONT

Functions of OLT

Optical line terminal (OLT) is the endpoint hardware equipment located in a central office of the PON network. Its basic function is to control the float information in optical distribution network (ODN) to go in both directions. OLT converts the standard signals used by fiber optic service (FiOS) to the frequency and framing used by PON system. In addition, it coordinates the multiplexing between the ONT conversion devices. There are two float directions for OLT system. One is the upstream direction to distribute different types of data and voice traffic from users. The other is the downstream direction which gets data, voice and video traffic from metro network or from a long-haul network and sends it to all ONT modules on the ODN.

OLT

How to Add or Delete ONT on OLT?
Way to Add ONT on OLT

If the password of an ONT is obtained, you can run the ONT add command to add the ONT offline. However, if the password is unknown, you can run the port portid ont-auto-find command in the GPON mode to enable the ONT auto-find function of the GPON port, and then run the ONT confirm command to confirm the ONT. When the ONT is added, you need to run the display ONT info command to see the current status of ONT. If the control flag is active, run state is online, config state is normal, and match state is match, then the ONT adding process is successful.

Way to Delete ONT on OLT

When you need to delete the ONT on OLT, please use the delete command. Then ONT configuration data is deleted with the deletion of the ONT and the online ONT is forced offline. ONT can’t be deleted when it has been configured with other services. You need to unbind the service first before delete the ONT.

How to Troubleshoot ONT?

To troubleshoot the ONT, you should remember that the most important step is to connect your computer directly to the ONT to see if the problem goes away. You can use the Ethernet cable for connection. If the problem still exists, you can reconnect the ONT power supply to clear its internal cache. If the network can not be restored after the above methods, maybe you need to consult professionals for help.

Conclusion

ONT and OLT are indispensable components in the GPON network system. If you are considering to purchase the ONT or OLT devices, FS.COM is a good place to go. Different types of ONT and OLT equipment are provided with high integration, flexible adaption and great reliability to meet all your requirements.

Related Article: Comparison Between EPON and GPON