LAN Data Link Layer Addressing

Last week, we discussed Fibre Channel addressing. This time, we’ll focus on data link layer technologies used in multi-access networks: Ethernet, Token Ring, FDDI, and other local area- or Wi-Fi technologies.

The first local area networks (LANs) ran on a physical multi-access medium. The first one (original Ethernet) started as a thick coaxial cable1 that you had to drill into to connect a transceiver to the cable core.

Later versions of Ethernet used thinner cables with connectors that you put together to build whole network segments out of pieces of cable. However, even in that case, we were dealing with a single multi-access physical network – disconnecting a cable would bring down the whole network.

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Cisco Intent-Based Networking: Part I – Introduction

 Introduction

This chapter introduces Cisco's approach to Intent-based Networking (IBN) through their Centralized SDN Controller, Cisco DNA Center, rebranded as Cisco Catalyst Center (from now on, I am using the abbreviation C3 for Cisco Catalyst Center). We focus on the network green field installation, showing workflows, configuration parameters, and relationships and dependencies between building blocks. The C3 workflow is divided into four main entities: 1) Design, 2) Policy, 3) Provision, and 4) Assurance, each having its own sub-processes. This chapter introduces the Design phase focusing on Network Hierarchy, Network Settings, and Network Profile with Configuration Templates. 

This post deprecates the previous post, "Cisco Intent-Based Networking: Part I, Overview."

Network Hierarchy

Network Hierarchy is a logical structure for organizing network devices. At the root of this hierarchy is the Global Area, where you establish your desired network structure. In our example, the hierarchy consists of four layers: Area (country - Finland), Sub-area (city - Joensuu), Building (JNS01), and Floor (JNS01-FLR01). Areas and Buildings indicate the location, while Floors provide environmental information relevant to wireless networks, such as floor type, measurements, and wall properties.


Network Settings

Network settings define device credentials (CLI, HTTP(S), SNMP, and NETCONF) required for accessing devices Continue reading

Debian on Mellanox SN2700 (32x100G)

Introduction

I’m still hunting for a set of machines with which I can generate 1Tbps and 1Gpps of VPP traffic, and considering a 100G network interface can do at most 148.8Mpps, I will need 7 or 8 of these network cards. Doing a loadtest like this with DACs back-to-back is definitely possible, but it’s a bit more convenient to connect them all to a switch. However, for this to work I would need (at least) fourteen or more HundredGigabitEthernet ports, and these switches tend to get expensive, real quick.

Or do they?

Hardware

SN2700

I thought I’d ask the #nlnog IRC channel for advice, and of course the usual suspects came past, such as Juniper, Arista, and Cisco. But somebody mentioned “How about Mellanox, like SN2700?” and I remembered my buddy Eric was a fan of those switches. I looked them up on the refurbished market and I found one for EUR 1’400,- for 32x100G which felt suspiciously low priced… but I thought YOLO and I ordered it. It arrived a few days later via UPS from Denmark to Switzerland.

The switch specs are pretty impressive, with 32x100G QSFP28 ports, which can be broken out to a set of Continue reading

My First Web Page

<h2>My First Web Page</h2>
<p>My first paragraph.</p>
<p>Never call dudud document.write after the document has finished loading.
<div id="om-utia0gbpx93d4wvo9abp-holder"></div>.
It will overwrite the whole document.</p>
<script>
document.write(5 + 6);
</script>

The post My First Web Page appeared first on Tigera.

Git Rebase: What Can Go Wrong?

Julia Evans wrote another must-read article (if you’re using Git): git rebase: what can go wrong?

I often use git rebase to clean up the commit history of a branch I want to merge into a main branch or to prepare a feature branch for a pull request. I don’t want to run it unattended – I’m always using the interactive option – but even then, I might get into tight spots where I can only hope the results will turn out to be what I expect them to be. Always have a backup – be it another branch or a copy of the branch you’re working on in a remote repository.

Git Rebase: What Can Go Wrong?

Julia Evans wrote another must-read article (if you’re using Git): git rebase: what can go wrong?

I often use git rebase to clean up the commit history of a branch I want to merge into a main branch or to prepare a feature branch for a pull request. I don’t want to run it unattended – I’m always using the interactive option – but even then, I might get into tight spots where I can only hope the results will turn out to be what I expect them to be. Always have a backup – be it another branch or a copy of the branch you’re working on in a remote repository.

SC23 Dropped packet visibility demonstration

The real-time dashboard is a joint InMon / Arista Network Research Exhibition, SC23-NRE-026 Standard Packet Drop Monitoring In High Performance Networks. a part of The International Conference for High Performance Computing, Networking, Storage, and Analysis (SC23) conference being held this week in Denver.
The conference network used in the demonstration, SCinet, is described as the most powerful and advanced network on Earth, connecting the SC community to the world.

The SC23-NRE-026 Standard Packet Drop Monitoring In High Performance Networks dashboard combines telemetry from all the Arista switches in the SCinet network to provide real-time network-wide view of performance. Each of the three charts demonstrate a different type of measurement in the sFlow telemetry stream:

  • Counters: Total Traffic shows total traffic calculated from interface counters streamed from all interfaces. Counters provide a useful way of accurately reporting byte, frame, error and discard counters for each network interface. In this case, the chart rolls up data from all interfaces to trend total traffic on the network.
  • Samples: Top Flows shows the top 5 largest traffic flows traversing the network. The chart is based on sFlow's random packet sampling mechanism, providing a scaleable method of determining the hosts and services responsible Continue reading

Nvidia planning 3 GPUs for sale in China to circumvent US restrictions: Reports

Chipmaker Nvidia is reportedly working on producing three new graphics processing units (GPUs) for sale in China in order to circumvent the new export restrictions imposed by the Biden administration.  The new chips — namely the H20, L20, and L2 — could go on sale in China from November 16 after the new US restrictions come into force, according to a news report from Chinastarmarket, which cites sources in the industrial supply chain put in place by Nvidia to manufacture these new GPUs.To read this article in full, please click here

Japanese government pledges further $13.3B to shore up domestic chip sector

The Japanese government has allocated an extra $13.3 billion (two trillion yen) to boost its domestic semiconductor industry.The funding is expected to be split between manufacturing and R&D, according to The Japan Times, which reported that the majority of the money will likely go to supporting TSMC and Rapidus. About $376 million (570 billion yen) will be assigned to a separate fund to enhance the stable supply of chips to Japan, the report said.The decision comes at the end of a year where both government subsidies and company investments and innovations have sought to significantly bolster the country’s chip manufacturing abilities and place it at the cutting edge of semiconductor technology.To read this article in full, please click here

KU040: Kubernetes Autoscaling Magic – Cost Control In Gen AI And LLMs With CAST AI (Sponsored)

In this sponsored episode of the Kubernetes Unpacked Podcast, we dive into the importance of cost and resource optimization with CAST AI. The truth is, it’s not just about saving money. The goal is ensuring that your apps are performing the way they should be. This not only saves customer frustration, but engineering frustration. We... Read more »

KU040: Kubernetes Autoscaling Magic – Cost Control In Gen AI And LLMs With CAST AI (Sponsored)

In this sponsored episode of Kubernetes Unpacked, we dive into the importance of cost and resource optimization with CAST AI. The truth is, it’s not just about saving money. The goal is ensuring that your apps are performing the way they should. This saves both customer and engineering frustration. We also explore from an engineering perspective how CAST AI uses AI in the background and how AI teams are building integrations into the product.

The post KU040: Kubernetes Autoscaling Magic – Cost Control In Gen AI And LLMs With CAST AI (Sponsored) appeared first on Packet Pushers.

Hedge 202: Internet Governance with George Michaelson

How is the Internet governed? Who sets the rules for the Internet, civil society, and government control? How much input should techies have, and how much should government control things? These are questions we don’t often ask, and yet are crucial to building and operating networks connected to the global Internet. George Michaelson joins Toms and Russ to talk about Internet governance—including contrary views of where things should be versus where they are.

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HN709: Protecting Data, Apps With Cloud DLP And CASB (Sponsored)

Cloud environments often have poor visibility and monitoring, and controlling access to sensitive corporate data is difficult. We speak with sponsor Palo Alto Networks about how it integrates CASB and Data Loss Prevention to control Web access and prevent sensitive information from leaking from your organization.

The post HN709: Protecting Data, Apps With Cloud DLP And CASB (Sponsored) appeared first on Packet Pushers.

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