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Category Archives for "Networking"

Demystifying &&, ||, and ! on Linux

The &&, ||, and ! operators allow you to run a lot of useful commands on Linux, but you first need to get used to syntax that is a little trickier than the if-then-else command you might normally use.To get started, I should explain that one thing the command examples in this post have in common is the use of something that I might call a shorthand “if” test. Here’s an example:$ [ -f donuts ] $ echo %?1 The -f donuts command asks if there is a file (-f) named “donuts”. Unless we display the return code afterwards with "echo $?", the result of the test is not displayed. In this case, it’s false (i.e., not zero), so we know the file doesn’t exist. No donuts for us!To read this article in full, please click here

Demystifying &&, ||, and ! on Linux

The &&, ||, and ! operators allow you to run a lot of useful commands on Linux, but you first need to get used to syntax that is a little trickier than the if-then-else command you might normally use.To get started, I should explain that one thing the command examples in this post have in common is the use of something that I might call a shorthand “if” test. Here’s an example:$ [ -f donuts ] $ echo %?1 The -f donuts command asks if there is a file (-f) named “donuts”. Unless we display the return code afterwards with "echo $?", the result of the test is not displayed. In this case, it’s false (i.e., not zero), so we know the file doesn’t exist. No donuts for us!To read this article in full, please click here

HP finishes the ultimate edge computing test: In space

You want edge computing? How about 250 miles straight up? HP Enterprise has announced that the Spaceborne Computer-2 (SBC-2) on the International Space Station (ISS) has successfully completed 24 research experiments in less than a year.The SBC-2 is the first in-space commercial edge computing and AI-enabled system to run on the ISS, according to HPE, and was installed in May 2021. The experiments involved real-time data processing and testing of new applications to prove reliability in space to increase autonomy for astronauts. HPE said the experiments reduced the time-to-insight from days and months to minutes.How to choose an edge gateway SBC-2 consists of HPE’s Edgeline Converged EL4000 Edge system, which is designed to perform in harsher edge environments, including space. SBC-2 is also made up of the HPE ProLiant DL360 high-performance server designed for workloads like HPC, and AI.To read this article in full, please click here

HPE finishes the ultimate edge computing test: In space

You want edge computing? How about 250 miles straight up? HP Enterprise has announced that the Spaceborne Computer-2 (SBC-2) on the International Space Station (ISS) has successfully completed 24 research experiments in less than a year.The SBC-2 is the first in-space commercial edge computing and AI-enabled system to run on the ISS, according to HPE, and was installed in May 2021. The experiments involved real-time data processing and testing of new applications to prove reliability in space to increase autonomy for astronauts. HPE said the experiments reduced the time-to-insight from days and months to minutes.How to choose an edge gateway SBC-2 consists of HPE’s Edgeline Converged EL4000 Edge system, which is designed to perform in harsher edge environments, including space. SBC-2 is also made up of the HPE ProLiant DL360 high-performance server designed for workloads like HPC, and AI.To read this article in full, please click here

HPE tests gear at the ultimate edge: Space

You want edge computing? How about 250 miles straight up? HP Enterprise has announced that the Spaceborne Computer-2 (SBC-2) on the International Space Station (ISS) has successfully completed 24 research experiments in less than a year.The SBC-2 is the first in-space commercial edge computing and AI-enabled system to run on the ISS, according to HPE, and was installed in May 2021. The experiments involved real-time data processing and testing of new applications to prove reliability in space to increase autonomy for astronauts. HPE said the experiments reduced the time-to-insight from days and months to minutes.How to choose an edge gateway SBC-2 consists of HPE’s Edgeline Converged EL4000 Edge system, which is designed to perform in harsher edge environments, including space. SBC-2 is also made up of the HPE ProLiant DL360 high-performance server designed for workloads like HPC, and AI.To read this article in full, please click here

HPE finishes the ultimate edge computing test: In space

You want edge computing? How about 250 miles straight up? HP Enterprise has announced that the Spaceborne Computer-2 (SBC-2) on the International Space Station (ISS) has successfully completed 24 research experiments in less than a year.The SBC-2 is the first in-space commercial edge computing and AI-enabled system to run on the ISS, according to HPE, and was installed in May 2021. The experiments involved real-time data processing and testing of new applications to prove reliability in space to increase autonomy for astronauts. HPE said the experiments reduced the time-to-insight from days and months to minutes.How to choose an edge gateway SBC-2 consists of HPE’s Edgeline Converged EL4000 Edge system, which is designed to perform in harsher edge environments, including space. SBC-2 is also made up of the HPE ProLiant DL360 high-performance server designed for workloads like HPC, and AI.To read this article in full, please click here

HPE tests gear at the ultimate edge: Space

You want edge computing? How about 250 miles straight up? HP Enterprise has announced that the Spaceborne Computer-2 (SBC-2) on the International Space Station (ISS) has successfully completed 24 research experiments in less than a year.The SBC-2 is the first in-space commercial edge computing and AI-enabled system to run on the ISS, according to HPE, and was installed in May 2021. The experiments involved real-time data processing and testing of new applications to prove reliability in space to increase autonomy for astronauts. HPE said the experiments reduced the time-to-insight from days and months to minutes.How to choose an edge gateway SBC-2 consists of HPE’s Edgeline Converged EL4000 Edge system, which is designed to perform in harsher edge environments, including space. SBC-2 is also made up of the HPE ProLiant DL360 high-performance server designed for workloads like HPC, and AI.To read this article in full, please click here

HP finishes the ultimate edge computing test: In space

You want edge computing? How about 250 miles straight up? HP Enterprise has announced that the Spaceborne Computer-2 (SBC-2) on the International Space Station (ISS) has successfully completed 24 research experiments in less than a year.The SBC-2 is the first in-space commercial edge computing and AI-enabled system to run on the ISS, according to HPE, and was installed in May 2021. The experiments involved real-time data processing and testing of new applications to prove reliability in space to increase autonomy for astronauts. HPE said the experiments reduced the time-to-insight from days and months to minutes.How to choose an edge gateway SBC-2 consists of HPE’s Edgeline Converged EL4000 Edge system, which is designed to perform in harsher edge environments, including space. SBC-2 is also made up of the HPE ProLiant DL360 high-performance server designed for workloads like HPC, and AI.To read this article in full, please click here

Upcoming Training: Network Troubleshooting

I’m teaching a three-hour webinar on troubleshooting on the 22nd of April:

This training focuses on the half-split system of troubleshooting, which is widely used in the electronic and civil engineering domains. The importance of tracing the path of the signal, using models to put the system in context, and the use of a simple troubleshooting “loop” to focus on asking how, what, and why are added to the half-split method to create a complete theory of troubleshooting. Other concepts covered in this course are the difference between permanent and temporary fixes and a review of measuring reliability. The final third of the course contains several practical examples of working through problems to help in applying the theory covered in the first two sections to the real world.

This is offered on Safari Books Online through Pearson. I think that if you register for the course, you can watch a recording later.

Register here.

The 2022 French Presidential election leaves its mark on the Internet

The 2022 French Presidential election leaves its mark on the Internet
The 2022 French Presidential election leaves its mark on the Internet

The first round of the 2022 French presidential elections were held this past Sunday, April 10, 2022, and a run-off will be held on April 24 between the top two candidates, Emmanuel Macron and Marine Le Pen. Looking at Internet trends in France for Sunday, it appears that when people were voting Internet traffic went down, and, no surprise, it went back up when results are coming in — that includes major spikes to news and election-related websites.

Cloudflare Radar data shows that Sundays are usually high-traffic days in France. But this Sunday looked a little different.

The seven-day Radar chart shows that there was a decrease in traffic compared to the previous Sunday between 08:00 and 16:00 UTC, that’s 10:00 and 18:00 in local time — bear in mind that polling stations in France were open between 08:00 and 19:00 (or 20:00 in big cities) local time. So, the decrease in traffic was ‘inside’ the period when French citizens were allowed to vote.

The 2022 French Presidential election leaves its mark on the Internet

That’s a similar trend we have seen in other elections, like the Portuguese one back in January 2022.

The time of the French election day with the largest difference compared to the previous Sunday was 14:00 Continue reading

Multicast PIM SSM – Source Specific Multicast

Multicast PIM SSM – Source Specific Multicast from a design point of view will be explained in this post. The Shortest Path Tree concept, Advantages, and disadvantages of Multicast PIM SSM will be covered as well.

What is Source Specific Multicast – PIM SSM?

PIM is a Multicast Routing Protocol. There are two categories of PIM protocol. PIM Dense mode and PIM Sparse Mode.

PIM Sparse Mode has 3 different modes of deployment. PIM SSM – Source Specific Multicast, PIM ASM – Any Source Multicast, and PIM Bidir – Bidirectional Multicast.

In this post, we will only cover PIM SSM but for the other PIM Sparse mode and PIM Dense mode design and deployment posts, place check Multicast category.

PIM SSM is called Source-Specific because Multicast receivers not only specify the Multicast Group that they are interested in but also they can signal to the network which course they are interested in or they are not interested in.

PIM SSM in the Routing Table

In the routers, we have multicast routing tables. SSM Multicast routing entries in the routers are seen as S, G.

S stands for multicast Source and G is used for multicast Group.

Source information has to Continue reading

BGP Private and Public AS Range

BGP Private and Public AS Range: On the internet, we have 2byte AS Numbers and 4 Byte AS Numbers. In this post, we will explain what are the BGP Private and Public AS Range for 2 byte AS and 4 byte AS numbers. Where Private BGP AS number is used and should be used and where Public AS Numbers in BGP is used and should be used. Not just where they should be used but also we will discuss where they shouldn’t be used too.

BGP Private AS Range for 2 Byte AS Numbers

A 2 byte AS number is a 16-bit number. This format provides for 65536 ASNs (0 to 65535). From these ASNs, the Internet Assigned Numbers Authority (IANA) reserved 1,023 of them (64512 to 65534) for private/internal usage.

BGP Private AS Range for 2-byte AS Number is between 64512 to 65535.

So we have 1023 BGP AS Numbers to use in a 2-byte ASN schema. Private AS numbers, similar to the Private IP address range (RFC 1918), should be used internally in the networks.

Not, external networks, such as the Internet. On Internet, in the Global Routing table, which is also known as Default Free Continue reading

9 hot jobs in the evolving data center

As data centers evolve, the skills needed to run them change as well, creating both a challenge and opportunity for current data-center workers.By necessity, modern data centers are at the forefront of efficiency for energy consumption, space utilization and automation. That efficiency extends to the personnel that staffs them and who must swiftly implement hardware, software, and architecture changes as best practices improve. That calls for new roles in administration, management, and planning.Existing career fields and legacy skill sets won’t cut it in many cases, but IT pros will be able to augment their existing skills to fill new roles as they open up—jobs with a more forward-looking focus.To read this article in full, please click here

9 hot jobs in the evolving data center

As data centers evolve, the skills needed to run them change as well, creating both a challenge and opportunity for current data-center workers.By necessity, modern data centers are at the forefront of efficiency for energy consumption, space utilization and automation. That efficiency extends to the personnel that staffs them and who must swiftly implement hardware, software, and architecture changes as best practices improve. That calls for new roles in administration, management, and planning.Existing career fields and legacy skill sets won’t cut it in many cases, but IT pros will be able to augment their existing skills to fill new roles as they open up—jobs with a more forward-looking focus.To read this article in full, please click here

Creating VRF Lite Labs With netsim-tools

I always found VRF lab setups a chore. On top of the usual IPAM tasks you have to create VRFs, assign route targets and route distinguishers, do that on every PE-router in your lab… before you can start working on interesting things.

I tried to remove as much friction as I could with the netsim-tools VRF configuration module – let me walk you through a few simple examples1 which will also serve to illustrate the VRF configuration differences between Cisco IOS and Arista EOS.

Read more …

Creating VRF Lite Labs With netlab

I always found VRF lab setups a chore. On top of the usual IPAM tasks you have to create VRFs, assign route targets and route distinguishers, do that on every PE-router in your lab… before you can start working on interesting things.

I tried to remove as much friction as I could with the netlab VRF configuration module – let me walk you through a few simple examples1 which will also serve to illustrate the VRF configuration differences between Cisco IOS and Arista EOS.

Read more …
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