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Category Archives for "Networking"

24 ways to check the status of files using if commands on Linux

There are a lot more ways to check files using if commands than many of us realize. Although this information is included in the bash man page, that man page has thousands of lines and you could easily find yourself paging down more than 100 times to reach it.This post, provides information on each option and examples for some of the most useful ones. [ Get regularly scheduled insights by signing up for Network World newsletters. ] Checking if a file exists One of the most commonly used tests for checking on files is if [ -f filename ]. This test will result in true if the file exists and is a regular file—not a directory or a symbolic link. You might use it like this:To read this article in full, please click here

24 ways to check the status of files using if commands on Linux

There are a lot more ways to check files using if commands than many of us realize. Although this information is included in the bash man page, that man page has thousands of lines and you could easily find yourself paging down more than 100 times to reach it.This post, provides information on each option and examples for some of the most useful ones. [ Get regularly scheduled insights by signing up for Network World newsletters. ] Checking if a file exists One of the most commonly used tests for checking on files is if [ -f filename ]. This test will result in true if the file exists and is a regular file—not a directory or a symbolic link. You might use it like this:To read this article in full, please click here

24 ways to check the status of files using if commands on Linux

There are a lot more ways to check files using if commands than many of us realize. Although this information is included in the bash man page, that man page has thousands of lines and you could easily find yourself paging down more than 100 times to reach it.This post, provides information on each option and examples for some of the most useful ones. [ Get regularly scheduled insights by signing up for Network World newsletters. ] Checking if a file exists One of the most commonly used tests for checking on files is if [ -f filename ]. This test will result in true if the file exists and is a regular file—not a directory or a symbolic link. You might use it like this:To read this article in full, please click here

24 ways to check the status of files using if commands on Linux

There are a lot more ways to check files using if commands than many of us realize. Although this information is included in the bash man page, that man page has thousands of lines and you could easily find yourself paging down more than 100 times to reach it.This post, provides information on each option and examples for some of the most useful ones. [ Get regularly scheduled insights by signing up for Network World newsletters. ] Checking if a file exists One of the most commonly used tests for checking on files is if [ -f filename ]. This test will result in true if the file exists and is a regular file—not a directory or a symbolic link. You might use it like this:To read this article in full, please click here

NVIDIA ConnectX SmartNICs

NVIDIA ConnectX SmartNICs offer best-in-class network performance, serving low-latency, high-throughput applications with one, two, or four ports at 10, 25, 40, 50, 100, 200, and up to 400 gigabits per second (Gb/s) Ethernet speeds.

This article describes how use the instrumentation built into ConnectX SmartNICs for data center wide network visibility. Real-time network telemetry for automation provides some background, giving an overview of the sFlow industry standard with an example of troubleshooting a high performance GPU compute cluster.

Linux as a network operating system describes how standard Linux APIs are used in NVIDIA Spectrum switches to monitor data center network performance. Linux Kernel Upstream Release Notes v5.19 describes recent driver enhancements for ConnectX SmartNICs that extend visibility to servers for end-to-end visibility into the performance of high performance distributed compute infrastructure.

The open source Host sFlow agent uses standard Linux APIs to configure instrumentation in switches and hosts, streaming the resulting measurements to analytics software in real-time for comprehensive data center wide visibility.

Packet sampling provides detailed visibility into traffic flowing across the network. Hardware packet sampling makes it possible to monitor 400 gigabits per second interfaces on the server at line rate with minimal CPU/memory overhead.
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What is CXL, and why should you care?

If you purchase a server in the next few months featuring Intel’s Sapphire Rapids generation of Xeon Scalable processor or AMD’s Genoa generation of Epyc processors, they will come with a notable new function called Compute Express Link (CXL)—an open interconnect standard you may find useful, especially in future iterations.CXL is supported by pretty much every hardware vendor and built on top of PCI Express for coherent memory access between a CPU and a device, such as a hardware accelerator, or a CPU and memory.PCIe is meant for point-to-point communications such as SSD to memory, but CXL will eventually support one-to-many communication by transmitting over coherent protocols. So far, CXL is capable of simple point-to-point communication only.To read this article in full, please click here

What is CXL, and why should you care?

If you purchase a server in the next few months featuring Intel’s Sapphire Rapids generation of Xeon Scalable processor or AMD’s Genoa generation of Epyc processors, they will come with a notable new function called Compute Express Link (CXL)—an open interconnect standard you may find useful, especially in future iterations.CXL is supported by pretty much every hardware vendor and built on top of PCI Express for coherent memory access between a CPU and a device, such as a hardware accelerator, or a CPU and memory.PCIe is meant for point-to-point communications such as SSD to memory, but CXL will eventually support one-to-many communication by transmitting over coherent protocols. So far, CXL is capable of simple point-to-point communication only.To read this article in full, please click here

What is CXL, and why should you care?

If you purchase a server in the next few months featuring Intel’s Sapphire Rapids generation of Xeon Scalable processor or AMD’s Genoa generation of Epyc processors, they will come with a notable new function called Compute Express Link (CXL)—an open interconnect standard you may find useful, especially in future iterations.CXL is supported by pretty much every hardware vendor and built on top of PCI Express for coherent memory access between a CPU and a device, such as a hardware accelerator, or a CPU and memory.PCIe is meant for point-to-point communications such as SSD to memory, but CXL will eventually support one-to-many communication by transmitting over coherent protocols. So far, CXL is capable of simple point-to-point communication only.To read this article in full, please click here

What is CXL, and why should you care?

If you purchase a server in the next few months featuring Intel’s Sapphire Rapids generation of Xeon Scalable processor or AMD’s Genoa generation of Epyc processors, they will come with a notable new function called Compute Express Link (CXL)—an open interconnect standard you may find useful, especially in future iterations.CXL is supported by pretty much every hardware vendor and built on top of PCI Express for coherent memory access between a CPU and a device, such as a hardware accelerator, or a CPU and memory.PCIe is meant for point-to-point communications such as SSD to memory, but CXL will eventually support one-to-many communication by transmitting over coherent protocols. So far, CXL is capable of simple point-to-point communication only.To read this article in full, please click here

Network Break 395: Broadcom Ships 51.2Tbps ASIC; Extreme’s New AP Goes Outdoors; Lloyd’s Rethinks Cyber Insurance Policies

This week's Network Break podcast drills into features in Broadcom's newest Tomahawk ASIC, a new Wi-Fi 6E from Extreme for outdoor use, and a $262 million infusion for the startup DriveNets. We also cover serious Apple vulnerabilities, why Lloyd's is rethinking cyber insurance for state-sponsored attacks, Cisco financial results, and more.

BrandPost: What’s the Difference Between SASE, SD-WAN, and SSE?

By: Derek Granath, Senior Director, SD-WAN Product and Technical Marketing at Aruba, a Hewlett Packard Enterprise company.A Quick History LessonBelieve it or not, the term Software-defined Wide Area Network (SD-WAN) was first introduced back in 2014, practically ancient history when it comes to networking at the edge. It’s now well recognized and increasingly adopted as the cloud-first way to transform WAN architecture, improving application performance, enabling more efficient connectivity, and reducing network complexity.Secure Access Service Edge, known as SASE, describes the cloud-first architecture for both WAN and security functions, all delivered and managed in the cloud. In short, SASE is a blend of SD-WAN and cloud-delivered security.To read this article in full, please click here

BrandPost: What’s the Difference Between SASE, SD-WAN, and SSE?

By: Derek Granath, Senior Director, SD-WAN Product and Technical Marketing at Aruba, a Hewlett Packard Enterprise company.A Quick History LessonBelieve it or not, the term Software-defined Wide Area Network (SD-WAN) was first introduced back in 2014, practically ancient history when it comes to networking at the edge. It’s now well recognized and increasingly adopted as the cloud-first way to transform WAN architecture, improving application performance, enabling more efficient connectivity, and reducing network complexity.Secure Access Service Edge, known as SASE, describes the cloud-first architecture for both WAN and security functions, all delivered and managed in the cloud. In short, SASE is a blend of SD-WAN and cloud-delivered security.To read this article in full, please click here

Internet Edge IP SLA Deep Dive

It is a common design to have an internet Edge router connected to two different internet service providers to protect against the failure of an ISP bringing the office down. The topology may look something like this:

Internet Edge HA scenario

The two ISPs are used in an active/standby fashion using static routes. This is normally implemented by using two default routes where one of the routes is a floating static route. It will look something like this:

ip route 0.0.0.0 0.0.0.0 203.0.113.1 name PRIMARY
ip route 0.0.0.0 0.0.0.0 203.0.113.9 200 name SECONDARY

With this configuration, if the interface to ISP1 goes down, the floating static route which has an administrative distance (AD) of 200 will be installed and traffic will flow via ISP2. The drawback to this configuration is that it only works if the physical interface goes down. What happens if ISP1’s CPE has the interface towards the customer up but the interface towards the ISP Core goes down? What happens if there is a failure in another part of the ISP’s network? What if all interfaces are up but Continue reading

Cisco DevNet certifications explained

The enterprise network is undergoing a fundamental transition from manual to automated, from hardware to software-defined, from tightly controlled to sprawling across SaaS, multi-cloud, remote work and IoT environments.Network professionals are expected to not only extend existing functionality across all of those environments, they must elevate the capabilities of the network to enable digital transformation. That means building a network that’s more agile, resilient, secure, scalable, observable and intelligent.To read this article in full, please click here

Cisco DevNet certifications explained

The enterprise network is undergoing a fundamental transition from manual to automated, from hardware to software-defined, from tightly controlled to sprawling across SaaS, multi-cloud, remote work and IoT environments.Network professionals are expected to not only extend existing functionality across all of those environments, they must elevate the capabilities of the network to enable digital transformation. That means building a network that’s more agile, resilient, secure, scalable, observable and intelligent.To read this article in full, please click here

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