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Category Archives for "Networking"

Using the Linux stat command to create flexible file listings

The stat command supplies a lot of detailed information on files.It provides not just the date/time of the most recent file changes, but also shows when files were most recently accessed and permissions changed. It tells you the file size in both bytes and blocks. It displays the inode being used by the file along with the file type. It includes the file owner and the associated user group both by name and UID/GID. It displays file permissions in both the “rwx” (referred to as the “human-readable” format) and numerically. On some systems, it might even include the date and time that a file was created (called its “birth”).[Get regularly scheduled insights by signing up for Network World newsletters.] In addition to providing all this information, the stat command can also be used to create file listings. These listings are extremely flexible in that you can choose to include any or all of the information described above.To read this article in full, please click here

IBM/Red Hat open hybrid-cloud application market

IBM and its Red Hat company have opened up what they call a one-stop-shop for customers looking to build, deploy and manage hybrid-cloud applications on-premises or in multicloud environments.With Red Hat Marketplace, enterprise customers can find and buy the  tools and services they need to build cloud-native applications across public and private cloud environments through one curated repository, Red Hat executives said.[Get regularly scheduled insights by signing up for Network World newsletters.] IBM and Red Hat executives said the enterprise software and service marketplace is specifically aimed at hybrid-cloud computing customers.To read this article in full, please click here

IBM/Red Hat open hybrid cloud application market

IBM and its Red Hat company have opened up what they call a one-stop-shop for customers looking to build, deploy and manage hybrid-cloud applications on-premises or in multicloud environments.With Red Hat Marketplace, enterprise customers can find and buy the  tools and services they need to build cloud-native applications across public and private cloud environments through one curated repository, Red Hat executives said.[Get regularly scheduled insights by signing up for Network World newsletters.] IBM and Red Hat executives said the enterprise software and service marketplace is specifically aimed at hybrid-cloud computing customers.To read this article in full, please click here

Cumulus Linux 4.2

Cumulus Linux is a network operating system for open networking hardware. Cumulus VX is a free virtual appliance that allows network engineers to experiment with Cumulus Linux and verify configurations before deploying into production. 
The Cumulus VX documentation describes how to build network topologies in KVM, VirtualBox, using VMWare hypervisors. If you want to run virtual machines locally, Cumulus in the Cloud is a free service that will allow you to access pre-built networks in the public cloud.

A key feature of Cumulus Linux is the use of the Linux kernel as the authoritative repository of network state. A result of this approach is that the behavior of a Cumulus Linux VX virtual appliance is the same as Cumulus Linux running on a hardware switch. For example, the open source FRR routing daemon shipped with Cumulus Linux uses the Linux netlink API to push routes to the kernel, which forwards packets in the virtual appliance. On a physical switch, routes are still pushed to the kernel, but kernel routing configuration is then offloaded to the switch ASIC so that packets bypass the kernel and are routed by hardware.

Cumulus Linux includes the open source Host sFlow agent. Here again, Continue reading

Virtual Open Office Hours – Mid September 2020

Virtual Open Office is a chance for people to gather and discuss any topics you find interesting. Open to Anyone. No cost or commitment. Just a chance to sit around and talk, like you were in the corridor at a conference.  I’ll be there with a coffee/tea or a beer/cocktail (as appropriate) Tuesday, September 15, […]

It Has to Work

From time immemorial, humor has served to capture truth. This is no different in the world of computer networks. A notable example of using humor to capture truth is the April 1 RFC series published by the IETF. RFC1925, The Twelve Networking Truths, will serve as our guide.

According to RFC1925, the first fundamental truth of networking is: it has to work. While this might seem to be overly simplistic, it has proven—over the years—to be much more difficult to implement in real life than it looks like in a slide deck. Those with extensive experience with failures, however, can often make a better guess at what is possible to make work than those without such experience. The good news, however, is the experience of failure can be shared, especially through self-deprecating humor.

Consider RFC748, which is the first April First RFC published by the IETF, the TELNET RANDOMLY-LOSE Option. This RFC describes a set of additional signals in the TELNET protocol (for those too young to remember, TELNET is what people used to communicate with hosts before SSH and web browsers!) that instruct the server not to provide random losses through such things as “system crashes, lost data, Continue reading

Network Break 300: Cisco Mixes Microservices And SD-WAN; Broadcom Rolls Out Gen7 Fibre Channel Switches

Network Break dives into a new Cisco project that ties microservices to SD-WAN, a CenturyLink outage, new vulnerabilities in IOS-XR, Broadcom's new Gen7 Fibre Channel switches, and more IT news.

The post Network Break 300: Cisco Mixes Microservices And SD-WAN; Broadcom Rolls Out Gen7 Fibre Channel Switches appeared first on Packet Pushers.

NSX for vSphere to NSX-T Migration Resources at VMworld 2020

VMworld, the industry’s largest virtualization-specific event, is right around the corner! As you get ready for VMworld, this blog is your resource for key sessions around migrating from NSX for vSphere to NSX-T. And, via the comments below, this blog is also your channel to connect back with us if you have any questions, need further clarifications, or would like a follow up call on migration strategies.

NSX for vSphere to NSX-T Migration Resources at VMworld 2020

Learn from the Experts at VMworld

So, you’re on NSX for vSphere and you’ve been coming across all the use cases addressed by NSX-T. To take advantage of those use cases, you decide you want to move to NSX-T. And you’re wondering:

  1. Are there any VMware-supported built-in tools?
  2. Can I do this by myself?
  3. Is there a migration process that resembles upgrading?
  4. Can this be done without adding net-new hardware?

We Answer Those Questions At VMworld Breakout Sessions

Join us at the VMworld breakout session VCNC1150: Migrating from NSX for vSphere to NSX-T Data Center Using Migration Coordinator as we explore various migration approaches and dive into a detailed demo of Migration Coordinator. Designed to provide the simple experience of an upgrade, Migration Coordinator is a built-in tool that allows our customers Continue reading

Heavy Networking 538: Running An Open, Automated Data Center Fabric With Nokia (Sponsored)

Today's show dives into Nokia's approach for automating and operating data center fabrics. In this sponsored episode we examine key elements of Nokia's approach including the SR Linux network OS and its Fabric Services Platform. Our guest is Steve Vogelsang, CTO for IP and Optical Networks at Nokia.

The post Heavy Networking 538: Running An Open, Automated Data Center Fabric With Nokia (Sponsored) appeared first on Packet Pushers.

What is SASE? A cloud service that marries SD-WAN with security

Secure access service edge (SASE) is a network architecture that rolls software-defined wide area networking (SD-WAN) and security into a cloud service that promises simplified WAN deployment, improved efficiency and security, and to provide appropriate bandwidth per application.Because it’s a cloud service, SASE (pronounced “sassy”) can be readily scaled up and scaled down and billed based on usage. As a result, it can be an attractive option in a time of rapid change.[Get regularly scheduled insights by signing up for Network World newsletters.] While some vendors in this space offer hardware devices to connect at-home employees and corporate data centers to their SASE networks, most vendors handle the connections through software clients or virtual appliances.To read this article in full, please click here

What is SASE? A cloud service that marries SD-WAN with security

Secure access service edge (SASE) is a network architecture that rolls software-defined wide area networking (SD-WAN) and security into a cloud service that promises simplified WAN deployment, improved efficiency and security, and to provide appropriate bandwidth per application.Because it’s a cloud service, SASE (pronounced “sassy”) can be readily scaled up and scaled down and billed based on usage. As a result, it can be an attractive option in a time of rapid change.[Get regularly scheduled insights by signing up for Network World newsletters.] While some vendors in this space offer hardware devices to connect at-home employees and corporate data centers to their SASE networks, most vendors handle the connections through software clients or virtual appliances.To read this article in full, please click here

What is SASE? A cloud service that marries SD-WAN with security

Secure access service edge (SASE) is a network architecture that rolls software-defined wide area networking (SD-WAN) and security into a cloud service that promises simplified WAN deployment, improved efficiency and security, and to provide appropriate bandwidth per application.Because it’s a cloud service, SASE (pronounced “sassy”) can be readily scaled up and scaled down and billed based on usage. As a result, it can be an attractive option in a time of rapid change.[Get regularly scheduled insights by signing up for Network World newsletters.] While some vendors in this space offer hardware devices to connect at-home employees and corporate data centers to their SASE networks, most vendors handle the connections through software clients or virtual appliances.To read this article in full, please click here

Understandability

According to Maor Rudick, in a recent post over at Cloud Native, programming is 10% writing code and 90% understanding why it doesn’t work. This expresses the art of deploying network protocols, security, or anything that needs thought about where and how. I’m not just talking about the configuration, either—why was this filter deployed here rather than there? Why was this BGP community used rather than that one? Why was this aggregation range used rather than some other? Even in a fully automated world, the saying holds true.

So how can you improve the understandability of your network design? Maor defines understandability as “the dev who creates the software is to effortlessly … comprehend what is happening in it.” Continuing—“the more understandable a system is, the easier it becomes for the developers who created it to change it in a way that is safe and predictable.” What are the elements of understandability?

Documentation must be complete, clear, concise, and organized. The two primary failings I encounter in documentation are completeness and organization. Why something is done, when it was last changed, and why it was changed are often missing. The person making the change just assumes “I’ll remember Continue reading

DHCP Relay Issues With Microsoft Surface Pro Docks and Junos

After deploying some new Juniper EX4600 core switches, my customer complained that he was experiencing about 45 seconds of delay in getting an IP address on a Surface Pro connected to a dock. The second time of connecting, it took about 8 seconds which was more acceptable. The 45 second delay came back every time they moved the Surface Pro to a new dock.

After ruling out a few things like Spanning Tree and LLDP, we isolated it down to the core switch. An older core switch elsewhere was configured for BootP Helper rather than DHCP relay, and clients connected to that did not have the problem.

Other devices didn’t exhibit the problem either – a Macbook was given an IP in the region of 4 seconds after connecting. The Surface Pro took 8 seconds consistently to connect when using a USB dongle. So the issue seemed to centre around the dock.

If you haven’t seen one of these before, they look like this – a black brick with some ports on it, supplied with power by another black brick:

The wire to the right of the image above ends in an edge connector that is plugged on to the Continue reading