Subnetting: Brushing up on the fundamentals

In the IT world, specifically in networking, there aren’t many aspects that are as much of an enigma as subnetting—the act of creating subnetworks.Subnets are logical divisions of an existing network that are defined by both class of IP address and the subnet mask. Often, consultants provide network design services to budding businesses to help establish a network that fits their needs at the time. But as the business grows or its needs change there may come a time when the initial network structure no longer works.IPv6 deployment guide I’m currently working on a project that fits that description to a tee. The network was conceived by consultants when there were not as many devices and users to accommodate. As the needs of the business grew, it became painfully obvious that a single /24 subnet that accommodates up to 254 hosts wasn’t enough anymore. So I’m building out a new network structure that can accommodate all of the devices we currently have, separated by types of devices, and with room for growth.To read this article in full, please click here

Response: Is Switching Latency Relevant?

Minh Ha left another extensive comment on my Is Switching Latency Relevant blog post. As is usual the case, it’s well worth reading, so I’m making sure it doesn’t stay in the small print (this time interspersed with a few comments of mine in gray boxes)


I found Cisco apparently manages to scale port-to-port latency down to 250ns for L3 switching, which is astonishing, and way less (sub 100ns) for L1 and L2.

I don’t know where FPGA fits into this ultra low-latency picture, because FPGA, compared to ASIC, is bigger, and a few times slower, due to the use of Lookup Table in place of gate arrays, and programmable interconnects.

Response: Is Switching Latency Relevant?

Minh Ha left another extensive comment on my Is Switching Latency Relevant blog post. As is usual the case, it’s well worth reading, so I’m making sure it doesn’t stay in the small print (this time interspersed with a few comments of mine in gray boxes)


I found Cisco apparently manages to scale port-to-port latency down to 250ns for L3 switching, which is astonishing, and way less (sub 100ns) for L1 and L2.

I don’t know where FPGA fits into this ultra low-latency picture, because FPGA, compared to ASIC, is bigger, and a few times slower, due to the use of Lookup Table in place of gate arrays, and programmable interconnects.

More FT8 propagation

Last month I graphed the distance to remote stations as a function of time of day.

Today I plotted the gridsquare locations on a world map:

Grid squares heard

Ignore the top right one. That’s “RR73”, and not a real grid square. The rest should be accurate.

More that can be done (more interesting with more data than I can get, though):

  • also take into account the received signal strength
  • …and number of unique callsigns per grid square
  • create animations over time

If I had access to the data from pskreporter I could even, instead of using just a callsign as input data, use a grid square as input.

So for example I could create an animation to show what the propagation was over the last week from any given gridsquare, and generate them on-demand.

Like last time the scripts are pretty hacky proof of concepts. But they work.

Verizon launches 5G fixed wireless in parts of 21 more cities

Communications giant Verizon last week launched 5G for Business Internet in 21 new markets, targeting SMBs and enterprises alike. 5G resources What is 5G? Fast wireless technology for enterprises and phones How 5G frequency affects range and speed Private 5G can solve some problems that Wi-Fi can’t Private 5G keeps Whirlpool driverless vehicles rolling 5G can make for cost-effective private backhaul CBRS can bring private 5G to enterprises The fixed-wireless plans provide download speeds of 100Mbps ($69/month), 200Mbps ($99/month), and 400Mbps ($199/month) with no data limits. Upload speeds are slower. Verizon is also offering a 10-year price lock for new customers with no long-term contract required.To read this article in full, please click here

Linux commands for testing connectivity and transfer rates

There are quite a few tools that can help test your connectivity on the Linux command line. In this post, we'll look at a series of commands that can help estimate your connection speed, test whether you can reach other systems, analyze connection delays, and determine whether particular services are available.ping The ping command is the simplest and most often used command for doing basic connectivity testing. It sends out packets called echo requests and are packets that request a response. The command looks for the responses and displays them along with how long each response took and then reports what percentage of the requests were answered.To read this article in full, please click here

Linux commands for testing connectivity and transfer rates

There are quite a few tools that can help test your connectivity on the Linux command line. In this post, we'll look at a series of commands that can help estimate your connection speed, test whether you can reach other systems, analyze connection delays, and determine whether particular services are available.ping The ping command is the simplest and most often used command for doing basic connectivity testing. It sends out packets called echo requests and are packets that request a response. The command looks for the responses and displays them along with how long each response took and then reports what percentage of the requests were answered.To read this article in full, please click here

Full Stack Journey 053: Exploring Developer Advocacy And Developer Relations

Today's Full Stack Journey delves into developer advocacy: what is it, why do organizations have this role, and what makes a good developer advocate? Host Scott Lowe has invited four practitioners to tackle these questions. He speaks with Jacquie Grindrod, Jeremy Meiss, Josh Wulf, and Ted Neward.

The post Full Stack Journey 053: Exploring Developer Advocacy And Developer Relations appeared first on Packet Pushers.

LinuxKit as a Commodity for Building Linux Distributions

Guest post by Docker Captain Gianluca Arbezzano

Recently Corey Quinn from LastWeekInAWS wrote an article that made me think “Nobody Cares About the Operating System Anymore”. Please have a look at it! I like the idea that nobody cares about where their application runs. Developers only want them running.

A bit of context about Tinkerbell

I am one of the maintainers for the Tinkerbell project. A bare metal workflows engine that heavily relies on containers and Docker to get its work done. It tries to find an answer for a reasonable question: how do we manage rooms of pieces of hardware? More in practice, how can we bring an API on top of everybody’s data centers?

Containers are the abstraction we decided to use when running reusable code (that we call actions) in somebody else’s hardware. Mainly because distribution, packaging, and runtime are solved issues. Everyone knows how to build, push and run a container.

I think this scenario compares well with the story Corey highlighted. Operating systems are an established, well-known abstraction for the majority of the use cases.

The special operating system for bare metal provisioning

The lifecycle of a bare metal server can be summarised as follows:

  1. Continue reading

Announcing Cloudflare Images beta to simplify your image pipeline

Announcing Cloudflare Images beta to simplify your image pipeline
Announcing Cloudflare Images beta to simplify your image pipeline

Today, we are announcing the beta of Cloudflare Images: a simple service to store, resize, optimize, and deliver images at scale.

In 2018, we launched Stream to provide a single product that could be used to store, encode, and deliver videos. With Cloudflare Images, we are doing for images what Stream did for videos. Just like Stream, Cloudflare Images eliminates the need to think about storage buckets, egress costs, and many other common problems that are solved for you out of the box. Whether you are building an ecommerce platform with millions of high-res product pictures and videos or a new app for creators, you can build your entire media pipeline by combining Cloudflare Images and Stream.

Fundamental questions for storing and serving images

Any time you are building infrastructure for image storage and processing, there are four fundamental questions you must answer:

  1. “Where do we store images?”
  2. “How do we secure, resize, and optimize the images for different use cases?”
  3. “How do we serve the images to our users reliably?”
  4. “How do we do all of these things at scale while having predictable and affordable pricing, especially during spikes?”

Cloudflare Images has a straightforward set Continue reading

VMware bundles support for the branch-of-one workforce

VMware has unveiled an integrated package of cloud security, access control and networking software aimed at addressing the key needs of today's COVID-19-driven remote workforce.VMware Anywhere Workspace brings together the company’s core enterprise software products, including its Workspace ONE unified endpoint management, Carbon Black Cloud cloud-native endpoint security, and secure access service edge (SASE) components, into a single system to support a widely distributed workforce. Read more: Who's selling SASE, and what do you get? "Enterprises are moving from simply supporting remote work to becoming distributed, anywhere organizations. Companies are rethinking where teams work, how they work, and how they support customers from wherever they are," Sanjay Poonen, chief operating officer, customer operations with VMware, wrote in a blog about the announcement. "To be successful, this means investing in technology and a long-term strategy to be a stronger, more focused and more resilient organization."  To read this article in full, please click here

VMware bundles support for the branch-of-one workforce

VMware has unveiled an integrated package of cloud security, access control and networking software aimed at addressing the key needs of today's COVID-19-driven remote workforce.VMware Anywhere Workspace brings together the company’s core enterprise software products, including its Workspace ONE unified endpoint management, Carbon Black Cloud cloud-native endpoint security, and secure access service edge (SASE) components, into a single system to support a widely distributed workforce. Read more: Who's selling SASE, and what do you get? "Enterprises are moving from simply supporting remote work to becoming distributed, anywhere organizations. Companies are rethinking where teams work, how they work, and how they support customers from wherever they are," Sanjay Poonen, chief operating officer, customer operations with VMware, wrote in a blog about the announcement. "To be successful, this means investing in technology and a long-term strategy to be a stronger, more focused and more resilient organization."  To read this article in full, please click here

The Future of Connectivity: Wi-Fi 6 and Smart Homes Explained

Wi-Fi has transformed the way we live, allowing us to work from any location, shop from the comfort of our armchairs, and benefit from a wide range of connected devices that would have been impossible if we were constrained by cables.The number of connected devices is growing faster than the number of global Internet users with  smart home devices like thermostats, smoke alarms and lighting systems making life more comfortable, safer, and more convenient.By 2023, Internet of Things (IoT) will account for half of the global device market and connected home applications will be the largest category. This is a huge opportunity for Communications Service Providers (CSPs) to offer additional services and generate revenues.To read this article in full, please click here

Feedback Requested: Chartering the MANRS Community

While MANRS has gone from strength to strength since its beginning in 2014, gaining attention, interest, and credibility from network operators worldwide, for the initiative to be sustainable and impactful in the long run there should be a stronger sense of ownership by the community. MANRS is an industry-led initiative whose participants set and develop […]

The post Feedback Requested: Chartering the MANRS Community appeared first on Internet Society.

Start building your own private network on Cloudflare today

Start building your own private network on Cloudflare today
Start building your own private network on Cloudflare today

Starting today, your team can create a private network on Cloudflare’s network. Team members click a single button to connect to private IPs in environments that you control. Cloudflare’s network routes their connection through a data center in one of over 200 cities around the world. On the other side, administrators deploy a lightweight software connector that replaces traditional VPN appliances.

Cloudflare’s private network combines IP level connectivity and Zero Trust controls. Thick clients like RDP software, SMB file viewers, or other programs can connect to the private IPs already in use in your deployment without any additional configuration. Coming soon, you’ll be able to layer additional identity-based network-level rules to control which users, from which devices, can reach specific IPs.

We are launching this feature as a follow-up to Cloudflare’s Developer Week because we are excited to give your development team, and your entire organization, a seamless platform for building and connecting your internal resources. We built this solution based on feedback from customers who want to move to a Zero Trust model without sacrificing some of the convenience of a private network.

We’re excited to give any team the ability to run their internal network on Cloudflare’s global Continue reading

Using Unequal-Cost Multipath to Cope with Leaf-and-Spine Fabric Failures

Scott submitted an interesting the comment to my Does Unequal-Cost Multipath (UCMP) Make Sense blog post:

How about even Large CLOS networks with the same interface capacity, but accounting for things to fail; fabric cards, links or nodes in disaggregated units. You can either UCMP or drain large parts of your network to get the most out of ECMP.

Before I managed to write a reply (sometimes it takes months while an idea is simmering somewhere in my subconscious) Jeff Tantsura pointed me to an excellent article by Erico Vanini that describes the types of asymmetries you might encounter in a leaf-and-spine fabric: an ideal starting point for this discussion.

Using Unequal-Cost Multipath to Cope with Leaf-and-Spine Fabric Failures

Scott submitted an interesting the comment to my Does Unequal-Cost Multipath (UCMP) Make Sense blog post:

How about even Large CLOS networks with the same interface capacity, but accounting for things to fail; fabric cards, links or nodes in disaggregated units. You can either UCMP or drain large parts of your network to get the most out of ECMP.

Before I managed to write a reply (sometimes it takes months while an idea is simmering somewhere in my subconscious) Jeff Tantsura pointed me to an excellent article by Erico Vanini that describes the types of asymmetries you might encounter in a leaf-and-spine fabric: an ideal starting point for this discussion.