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How to Upgrade Cumulus Linux on N-Series Switches?

In the previous posts, we have introduced lots of details about Cumulus Linux, a network operating system. Also, we have talked about how to install Cumulus Linux on FS N-series switches like the 100GbE switch. In this post, we will solve another Cumulus Linux related question concerned by most of our users: how to upgrade Cumulus Linux on an N-series network switch?

Before Upgrading Cumulus Linux

Before any update, you should consider the migration and backup of some important data or files in case of any accident or emergency. In that way, being clear about the location of your configuration data is crucial before updating Cumulus Linux. Just like other Linux operating system distributions, the /etc directory is the primary location for all configuration data in Cumulus Linux. In the following figures, we list some files and as well as their directories that you are likely to do the backup.

Cumulus Linux Network Configuration Files

Figure 1: Cumulus Linux Network Configuration Files

Additional Commonly Used Files

Figure 2: Additional Commonly Used Files

Note: If you are using the root user account, consider including /root/. If you have custom user accounts, consider including /home//.

Upgrading Processes

Basically, there are two methods to upgrade Cumulus Linux: disk image install and package upgrade. According to different environment and preferences, the upgrade can be achieved in different ways. In this part, we will guide you on how to use these two ways one by one. By the way, if you are using MLAG to dual connect two switches in your environment, there are additional steps to follow. You can refer to the guide:Upgrade Switches in an MLAG Pair.

Solution 1: Installing A Disk Image

When you are performing a rolling upgrade in a production environment and using up-to-date and comprehensive automation scripts, the disk image installation will be recommended. It enables you to choose the exact release to which you want to upgrade. Moreover, it is the only method available to upgrade your switch like a 10GbE switch to a new release train (for example, from 2.5.6 to 3.7.0) or from a release earlier than 3.6.2.
To apply this upgrade, you need to use ONIE (open network install environment), which allows the installation of network operating systems (NOS) on a bare metal switch. FS N-series switches all include an ONIE installer. There are mainly six steps you can follow with:

1. Back up the configurations off the switch.

2. Download the Cumulus Linux image you want to install.

3. Install the disk image with the onie-install -a -i command, which boots the switch into ONIE. There are various ways to install the disk image, such as using FTP, a local file, or a USB drive. In figure 3, we demonstrate how to install image from a web server as your reference. After disk image installed, the switch can be rebooted.

Disk Image Install

Figure 3: Disk Image Install

4. Restore the configuration files to the new release—ideally with automation.

5. Verify correct operation with the old configurations on the new release.

6. Re-install third-party applications and associated configurations.

Solution 2: Upgrading Packages

Package upgrade is recommended if you are upgrading from Cumulus Linux 3.6.2 or later, or if you use third-party applications (package upgrade does not replace or remove third-party applications, unlike disk image install). When upgrading, configuration data stays in place. If the new release updates a configuration file that you changed previously, you are prompted for the version you want to use or if you want to evaluate the differences. Altogether, there are six steps as follows:

1. Back up the configurations from the switch.

2. Apply the following command to fetch the latest update metadata from the repository.

Command for the Latest Update Metadata

3. Review potential upgrade issues (in some cases, upgrading new packages might also upgrade additional existing packages due to dependencies). Run the following command to see the additional packages that will be installed or upgraded.

Command for Additional Packages

4. Upgrade all the packages to the latest distribution.

Command to the Latest Distribution

5. Reboot the switch if the upgrade messages indicate that a system restart is required.

Command to Reboot the Switch

6. Verify correct operation with the old configurations on the new version.

Questions & Answers

Besides the procedures to upgrade Cumulus Linux, we also list some questions concerned most by our FS customers.

1. How to Deal With Upgrade Failures?

Even the most well planned and tested upgrades can result in unforeseen problems. If you fail to upgrade Cumulus Linux, sometimes the best solution is to roll back to the previous state. You can refer to the following three techniques:

  • Back out individual packages: If you identify the problematic package, you can downgrade the affected package directly. In rare cases, you might need to restore the configuration files from backup or edit to back out any changes made automatically by the upgrade package.
  • Flatten and rebuild: use orchestration tools to re-install the previous OS release from scratch and then rebuild the configuration automatically.
  • Backup and restore: restore to a previous state, using a backup captured before the upgrade.
2. Will Future Software Updates for Cumulus Linux Be Free?

For FS N-series switches, the default validity of Cumulus Linux is one year. If Cumulus Linux OS is upgraded after 1 year, the customer can’t upgrade it for free and needs to renew the software support. Even if the software support service has been expired, you are allowed to use your current software as usual. By the way, we also provide a three-year software support fee option and a five-year software support fee option. The longer for OS support you choose, the more economical the switch will be.

3. Who Will Cover Technical Support?

FS will provide five-year tech support for the hardware. As for the problems about Cumulus Linux, FS and Cumulus will solve it together. Moreover, as one of the Linux distributions, the source code of Cumulus Linux is also freely available to everyone to use, modify or share such as GitHub. Just like the above question about the software update, the default validity of technical support for Cumulus Linux is one year. One year later, you can renew the support term.

Summary

In this post, we mainly focus on how to upgrade the Cumulus Linux on FS N-series switches. In addition, we list three after-sales related questions frequently asked by our FS customers.

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.

VXLAN

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

 

EVPN

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

 

LNV

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 10.2.1.1 for leaf 1 and 10.2.1.2 for leaf 2.

Summary

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.

Conclusion

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.

VLAN

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

Pros

  • 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

Cons

  • 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

Pros

  • 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)

Cons

  • 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

Summary

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?