Tag Archives: network switch

An Overview on EVPN and LNV

Bombarded with assorted network applications and protocols, the technologies and solutions for network virtualization delivery have been enriched greatly over past years. Among those technologies, VXLAN, also called virtual extensible local area network, is the key network virtualization. It enables layer 2 segments to be extended over an IP core (the underlay). The initial definition of VXLAN (RFC 7348) only relied on a flood-and-learn approach for MAC address learning. Now, a controller or a technology such as EVPN and LNV in Cumulus Linux can be realized. In this post, we are going to make an exploration on those two techniques: LNV and EVPN.


Figure 1: VXLAN

What Is EVPN

EVPN is also named as Ethernet VPN. It is largely considered as a unified control plane solution for the controller-less VXLAN, allowing for building and deploying VXLANs at scale. The EVPN relies on multi-protocol BGP (MP-BGP) to transport both layer 2 MAC and layer 3 IP information at the same time. It enables a separation between the data layer and control plane layer. By having the combined set of MAC and IP information available for forwarding decisions, optimized routing and switching within a network becomes feasible and the need for flooding to do learning gets minimized or even eliminated.

What Is LNV

LNV is the short of lightweight network virtualization. It is a technique for deploying VXLANs without a central controller on bare metal switches. Typically, it’s able to run the VXLAN service and registration daemons on Cumulus Linux itself. The data path between bridge entities is established on the top of a layer 3 fabric by means of a simple service node coupled with traditional MAC address learning.

The Relationship Between EVPN and LNV

From the above wiki of the EVPN and LNV, it’s easy for us to notice these two technologies are both the applications of VXLAN. For LNV, it can be used to deploy VXLAN without an external controller or software suite on the bare-metal layer 2/3 switches running Cumulus Linux network operating system (NOS). As for EVPN, it is a standards-based control plane for VXLAN, which can be used in any usual bare-metal devices, such as network switch and router. Typically, you cannot apply LNV and EVPN at the same time.

Apart from that, the deployments for EVPN and LNV are also different. Here, we make a configuring model for each of them for your better visualization.

EVPN Configuration Case



Figure 2: EVPN

In the EVPN-VXLAN network segments shown in Figure 2 (Before), hosts A and B need to exchange traffic. When host A sends a packet to host B or vice versa, the packet must traverse the switch A, a VXLAN tunnel, and the switch B. By default, routing traffic between a VXLAN and a Layer 3 logical interface is disabled. If the functionality is disabled, the pure Layer 3 logical interface on the switch A drops Layer 3 traffic from host A and VXLAN-encapsulated traffic from the switch B. To prevent the pure Layer 3 logical interface on the switch A from dropping this traffic, you can reconfigure the pure Layer 3 logical interface as a Layer 2 logical interface, like Figure 2 (After). After that, you need to associate this interface with a dummy VLAN and a dummy VXLAN network identifier (VNI). Then, an Integrated routing and bridging (IRB) interface need to be created, which provides Layer 3 functionality within the dummy VLAN.

LNV Configuration Case



Figure 3: LNV

The two layer 3 switches are regarded as leaf 1 and leaf 2 in the above figure. They are running with Cumulus Linux and have been configured as bridges. Containing physical switch port interfaces, the two bridges connect to the servers as well as the logical VXLAN interface associated with the bridge. After creating a logical VXLAN interface on both leaf switches, the switches become VTEPs (virtual tunnel end points). The IP address associated with this VTEP is most commonly configured as its loopback address. In the image above, the loopback address is for leaf 1 and for leaf 2.


In this post, we have introduced the two techniques of network virtualization: EVPN and LNV. These two applications of network virtualization delivery share some similarities, but also quite a lot of differences. Being satisfied with the simplicity, agility, and scalability over the network, the EVPN has been a popular choice in the market.

How to Choose a Gigabit Network Switch?

Gigabit network switch is the most commonly used equipment in data centers. Before choosing the best network switch for the current or future network, people can type “Ethernet switch” into the online shopping site or search engine, they may find a ton of listings for switches of all kinds and price levels. It’s not an easy job to find one. Then how to choose a Gigabit network switch in order to avoid buying the wrong device or overspending needlessly?

Gigabit network switch is widely used

Figure: Gigabit network switch is widely used.

Types of Gigabit Network Switch

Gigabit Ethernet switch can be divided into unmanaged, managed and PoE categories.

Unmanaged switches use the plug-and-play design that means they only allow Ethernet devices to communicate with one another. They are shipped with fixed configuration and don’t allow any changes to this configuration. This type of network switch is normally found in home networks or small business.

Managed switches offer all the features of unmanaged switches and are capable of configuring, managing and monitoring one’s LAN. Users have greater control over how data travels over the network and decide which one has access to it.

PoE switches support electrical power and data transmission over one network cable, which will greatly simplify the cabling process. Using a PoE switch, people don’t need to worry about power outlet when deploying network devices.

Features of Gigabit Network Switch

With a network switch, users can have different networked devices on their desks as well as bandwidth-intensive applications that require high rates of data transmission and no tolerance for congestion. These switches are the basics of modern wired network. They can not only provide the connections to PCs and other devices in a wide variety of fields, but also support the cloud storage of servers. With new trends like SDN and the IoT transforming the industry, people have to get the features that they need from the switches, so that they would know which switch is the one that they need.

How to Choose a Gigabit Network Switch?

Here are the most important facts you should consider when choosing a Gigabit network switch.

  • Choose the role of the switch. If you are just looking for a device to extend your wired network at home, one unmanaged switch is suitable. And an 8 port Ethernet switch or 12 port switch is enough for home network. If you want to find a switch for a large network, you may buy one or more managed switches acting as core switches. 24 port and 48 port PoE managed switches are the right choice.
  • Choose the forwarding rate of the switch. Gigabit switches have different processing rate. Processing and forwarding data rates are very important. The processing rate becomes lower, the forwarding rate will be slower. This may make the switch unable to accommodate full wire-speed communication across all the ports. So people should figure out what forwarding rate they need before buying a Gigabit switch.


From the above, we know how to choose a Gigabit network switch. If you have decided to buy a network switch, welcome to visit FS.COM. FS has a good selection of 10Gb switch, 40G or even 100G switch and PoE switch for home and office users.

How to Mount a Network Switch to a Rack?

A network switch has been recognized as one of the most important devices for today’s networking technology. It allows simultaneous transmission of multiple packets and partition a network more efficiently than bridges or routers. The rack mount switch can be installed in a standard 19-inch equipment rack or on a desktop or shelf. So how do you mount a network switch to a rack to establish network wiring connections? Here’s a step-by-step guide to teach you how to mount a network switch to a rack.

Preparations Before Mounting the Network Switch

Before rack mounting the switch, please pay attention to the following factors:

  • Location: The site should be at the center of all the devices you want to link and near a power outlet, so that it is accessible for installing, cabling and maintaining the devices in the rack.
  • Temperature: Since the temperature within a rack assembly may be higher than the ambient room temperature, check that the rack-environment temperature is within the specified operating temperature range (0 to 40 °C).
  • Mechanical Loading: Do not place any equipment on top of a rack-mounted unit.
  • Circuit Overloading: Be sure that the supply circuit to the rack assembly is not overloaded.
  • Grounding: The switch rack should be properly grounded.

How to Mount a Network Switch to a Rack?

Step1. Attaching the Brackets to the Switch

Attach the brackets to the network switch using the screws provided in the mounting accessory.

network switch to rack

Step2. Installing the Switch in the Rack

Mount the switch in the rack with the optional rack mount kit, usually using the rack-mounting screws. Be sure to secure the lower rack-mounting screws first to prevent the brackets being bent by the weight of the switch.

switch rack

Step3. Adding Other Switches into the Rack

If there is only one data switch to be installed in the rack, then you can make the connection to a power source now. If there are multiple switches to be mounted, you need to install the another switch on the top of the first one in the rack, and then attach the power cords.

Step4. Attaching the Power Cords

After you complete mounting all of the switches in the rack, it’s time to connect the switch rack to the power source. Remember to verify that you have the correct power supply (AC-input or DC-input and the correct wattage) for your configuration.

Caution: To prevent bodily injury when mounting or servicing the switches in a rack, you must take special precautions to ensure that the system remains stable. The following guidelines are provided to ensure your safety:

  • This network switch should be mounted at the bottom of the rack if it is the only unit in the rack.
  • When mounting the switch in a partially filled rack, load the rack from the bottom to the top with the heaviest component at the bottom of the rack.
  • If the rack is provided with stabilizing devices, install the stabilizers before mounting or servicing the switches in the rack.

Establishing Network Wiring Connections

After mounting your network switches to a rack, you can establish the network wiring connections according to your requirements now. If you’re using a Gigabit Ethernet switch, it can be connected to 10, 100 or 1000Mbps network interface cards in PCs and servers, as well as to other switches and hubs. It may also be connected to remote devices using optional SFP transceivers. No matter which type of network switches you are using, make sure that they are securely mounted in the rack and connected to the corresponding networking wiring systems.

Layer 2 vs Layer 3 Switch: How to Choose for VLAN?

With the advent of VLAN (Virtual Local Area Network), network managers can logically divide the physical LAN into different broadcast domains by spanning across multiple switches or even routers. The first series of VLAN switches on the market are Layer 2 switches which operate at Layer 2 of the ISO Reference Model. Soon afterwards, Layer 3 switches emerge as alternatives for VLAN and have gained incremental popularity. Layer 2 vs Layer 3 switch, which is more suitable for VLAN? We’re gonna elaborate it in this post.


Layer 2 Switch—Switching Layer for OSI Model

A Layer 2 switch is a type of network switch or device that works on the data link layer via OSI (Open Systems Interconnection) model and utilizes MAC address to determine the path through which the frames are to be forwarded. It uses hardware based switching techniques to connect and transmit data in VLAN. By looking at the destination MAC address in the frame header, the Layer 2 switch interconnects multiple end nodes of VLAN and intelligently forwards traffic between them without unnecessary flooding of frames onto the network. Generally speaking, Layer 2 switches come with different types of interfaces like 10 Mbps, 100 Mbps, 1 Gbps, 10 Gbps, etc. They can support full-duplex communication on each of its port. They expand network by connecting to the rest of the devices in the fabric through high speed ports that can be connected to either another Layer 2 or Layer 3 switch.

Pros and Cons


  • Forwards packets based on the unique Media Access Control (MAC) address of each end station
  • Information is easily retrieved and data packets transferred quickly at the wire speed of the network
  • No setup or management is required
  • Cheap and easy to deploy
  • Improve security with low latency
  • Flow accounting capabilities


  • Can not apply any intelligence when forwarding packets
  • Unable to route packets based on IP address
  • Can not guarantee bandwidth to Voice over IP (VoIP) users

Layer 3 Switch—Routing Layer for Sub Network

Layer 3 switch, known as the routing layer, can provide logical partitioning of sub networks with scalability, security, and Quality of Service (QoS). As an enhancement feature, QoS goes beyond the simple packet prioritization found in CoS by providing bandwidth reservation and packet delay bounding. In Layer 3 system, the packets are sent to a specific next-hop IP address, based on destination IP address. Different from MAC addresses of Layer 2 switch, each IP packet in Layer 3 switch contains source and destination IP addresses. The backbone of the Internet, along with those of many large organizations, is built upon a Layer 3 foundation. The functions of a Layer 3 switch (or multilayer switch) combine some features of a Layer 2 switch and a router.

Pros and Cons


  • Use logical addressing to determine the paths to destination networks
  • Intelligent packet forwarding (routing) based on Layer 3
  • Enable a router to link different sub networks together
  • Segment a network into two or more VLANs
  • Enhance security controls to prevent unauthorized setup changes
  • Provide guaranteed Quality of Service (QoS)


  • Extra processing power and memory is required for Layer 3 switching
  • Prices are higher than for a Layer 2 switch
  • Require setup and management

Layer 2 vs Layer 3 Switch: How to Choose for VLAN?

Layer 2 vs Layer 3 switch: how to choose for VLAN? Small networks can be built using just Layer 2 devices, but most corporate networks contain a mix of Layer 2 and Layer 3 switches as illustrated in the figure below. The most significant difference between Layer 2 and Layer 3 switch is the routing method. Layer 3 switch is capable of inter-VLAN routing and does not need additional device connected like router on-a-stick. Since network architectures on Layer 2 switching allow end station connectivity, it is often practical to construct a VLAN via Layer 2 switch only. Because it can provide simple, inexpensive, high-performance connectivity for hundreds or even thousands of end stations. However, Layer 3 switches also maintained a presence at many points within a corporate network. For a while it presents minimal problems, since a majority of the data traffic stayed local to the sub network, which was increasingly being serviced by a Layer 3 switch.

layer 2 vs layer 3 network


When it comes to the choice between Layer 2 switch vs Layer 3 switch, remember that both Layer 2 and Layer 3 switch have seen the most striking infrastructure for VLAN over the past decade. Whether to choose a Layer 2 vs Layer 3 switch is dependent upon many factors, such as routing method, speed requirement, networking design, as well as your budge. But where to get reliable and high performance Layer 2 and Layer 3 network switch? FS.COM provides a full set of gigabit switch, 10gb switch, 40gb switch and 100gb switch with Layer 2 or Layer 3 feature, which can support advanced hardware based VLAN deployment.

Related Article: Layer 2 vs Layer 3 Switch: Which One Do You Need?

The Rise of White Box Switches

White-box switch is nothing new to us. ODMs (original design manufacturers) have been building hardware for well-known vendors for many years. These vendors take the ODM hardware, install their operating system, and sell the unit as a bundle, often attaching a support contract. Until now many companies like FS are also getting into the game of producing white-box switches. White-box switches look just like any other switch, which are gaining increasing attention in next generation data center deployments, with many software-defined networking (SDN) startups offering solutions that include them. Enterprises are wondering how white-box switches will impact their data center plans. So what are white box switches?

What Is a White Box Switch?

white box switches

A white box switch is a network switch which comes with an installed operating system. It can be used as a standard for the base of hardware system elements. In the case of operating systems, white box switches are generally preinstalled on the system, or can be installed later. Loading of the white box switch is not difficult and can be done in a short period of time. They are generally used with SDNs and particularly useful in terms of a networking approach where the control is generated from the physical infrastructure after decoupling it. It can act as an efficient open-source tool for management of materials and information on a device.

And the major difference between traditional black box switch and white box switch is that the first one can’t be programmed but the later one can be programmed. With white box switches, a service can be programmed by using switch controller like ONOS while traditional black box switch provides very limited features and every time when you need to update something you have to log into switches and then change the rules. The white box switches are flexible, fast and inexpensive, which is why many opt for this type of switch.

Reasons for Buying White Boxes

Although white box switches have been around for years, the adoption has been limited to niche companies that have large engineering departments. The rise of software-defined networking (SDN) has brought them into the public eye, though, as a lower-cost alternative to traditional network hardware. In fact, some of the early messaging around SDN revolved around using white boxes as a complete replacement for all network hardware. Besides, many improvements have been made in white boxes during the past few years. So if you ask me why it is the time of white box switches and why you should buy white box switches. Here I’ve got a number of reasons for you:

  • 3-year ROI. A low-cost product can get ROI (return on investment) in less time and be replaced sooner. Faster hardware rotation equals more innovation/feature adoption.
  • Software bugs. Vendors take months to locate, accept, and fix bugs, which has enormous impact on your business. With OCP-compliant white boxes, you can switch software and keep your business alive, or work around slow vendor support.
  • Self-sparing. For some/most use cases, self-sparing is better than relying on vendor inventory. When products are cheap, you can hold inventory in your data center and bring MTTR down to hours instead of days.
  • Cost and reliability. What the customer is often paying for is the software that rides on top of the hardware and the logo. From a reliability standpoint, white boxes are on par with brand-name systems because they are actually the same hardware.
  • SDN. Move your operational focus from a vendor-specific CLI to an SDN solution. If you’re concerned about having multiple vendors to operate, then buy a SDN solution that is device independent.
  • Network operations. Many engineers may ask questions like “Do I have to write my own operating system?” “How do I install a network operating system” “What do I buy?” when considering a white box switch. Now, they can be reassured because white boxes can now be purchased from mainstream network vendors such as FS and HP. Also, when one purchases a white box, those suppliers will offer the kind of technical support most engineers need.

White boxes are certainly ready for mainstream adoption. Although they aren’t for every use case, but in the right situation, like an SDN deployment, they can be as good or better than traditional switches with a much lower price point and equivalent operational costs. If you want to purchase one, you may visit FS.COM where you can find the best-value and cost-efficient white box switch.

Related article: What White Box Switch Means to SDN Deployment