Comparing Forwarding Performance of Data Center Switches

One of my subscribers is trying to decide whether to buy an -EX or an -FX version of a Cisco Nexus data center switch:

I was comparing Cisco Nexus 93180YC-FX and Nexus 93180YC-EX. They have the same port distribution (48x 10/25G + 6x40/100G), 3.6 Tbps switching capacity, but the -FX version has just 1200 Mpps forwarding rate while EX version goes up to 2600 Mpps. What could be the reason for the difference in forwarding performance?

Both switches are single-ASIC switches. They have the same total switching bandwidth, thus it must take longer for the FX switch to forward a packet, resulting in reduced packet-per-seconds figure. It looks like the ASIC in the -FX switch is configured in more complex way: more functionality results in more complexity which results in either reduced performance or higher cost.

Read more …

Network Centrality and Robustness

Introduction

A system is robust if the failure of some components doesn’t affect its function. As network engineers, we face various types of network failures like link, node failures all the time.

Generally, we use various Network modeling tools like Cariden(WAE), WANDL, etc. to model failures and see how the network reacts under a given failure condition. The components which are in play are:

  1. Type and Number of failures. Type: Link, Node. Number of Failures: Single or Double.
  2. Routing protocols running on top of the network and there reaction to the failure. Example: RSVP-TE, Pure IGP, SR-TE etc.
  3. Network flows and their volume.
  4. Network Topology.

In this blog post, we will focus purely on #4 Network topology and certain characteristics of topology, which may make them more robust than other topologies.

Key Idea

The network topology may have some critical nodes. If we can identify them and take them out of the service, they will significantly impact the functionality of the network. For example, in the case of a Hub and Spoke topology, if a Hub is out of service, it affects all the spokes vs. a spoke out of service. We can make this hub and spoke topology more Continue reading

pygnmi 11. Measuring Automated Testing with Coverage.py and Pytest

Hello my friend,

It is been a while since we posted our last blogpost, which was touching Infrastructure aspects of building Multi Server Cloud with ProxMox. After summer break we continue our blogging and developing activities at Karneliuk.com. Today we’ll show some backstage of the software development of the pygnmi.



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What is Automation? Network Automation?

In a nutshell, Automation and Network Automation are just subset of tasks from a broader topic called Software Development. With the move of the world towards Industry 4.0, the digital economy growth and others, all sort of applications are becoming more widely used. In order you create a history, and not being a part of that in the past, you shall know the principles of software development and be able to create applications yourselves. Sounds complicated? It may be, indeed. However, with our Network Automation Training you definitely will have a break-through in the software development world.

At our Continue reading

Getting Blasted by Backdoors

Open Door from http://viktoria-lyn.deviantart.com/

I wanted to take minute to talk about a story I’ve been following that’s had some new developments this week. You may have seen an article talking about a backdoor in Juniper equipment that caused some issues. The issue at hand is complicated at the linked article does a good job of explaining some of the nuance. Here’s the short version:

  • The NSA develops a version of Dual EC random number generation that includes a pretty substantial flaw.
  • That flaw? If you know the pseudorandom value used to start the process you can figure out the values, which means you can decrypt any traffic that uses the algorithm.
  • NIST proposes the use of Dual EC and makes it a requirement for vendors to be included on future work. Don’t support this one? You don’t get to even be considered.
  • Vendors adopt the standard per the requirement but don’t make it the default for some pretty obvious reasons.
  • Netscreen, a part of Juniper, does use Dual EC as part of their default setup.
  • The Chinese APT 5 hacking group figures out the vulnerability and breaks into Juniper to add code to Netscreen’s OS.
  • They Continue reading

Weekend Reads 090321


In our professional practice, we are often called to perform rapid, approximate calculations without a calculator. Any available scrap of paper such as an envelope will do to scribble on.


The wireless carrier initially confirmed 47.8 million former, prospective and existing customers were impacted, but found the data of an additional 5.3 million customers was compromised.


A recent measurement study suggests that BBR is already being deployed by 22% of the Alexa Top 20k websites on the Internet.


Zero trust improves the security of IT environments as demonstrated over time by reduced attacker dwell time. The challenge many people face is understanding where to begin.


In recent months, we’ve been sharing information collected by APNIC honeypots with our community at several conferences, seminars, and workshops. ‘Information’ here basically means observations from the logs/traffic, as well as artefacts collected (such as scripts and binaries).


The Internet plays a crucial role in our increasingly digital daily lives. But who shapes and governs the patchwork that enables this essential utility? And how do their actions bear on the rights and interests of users all over the world?


We are facing the same paradox with respect to privacy and influence on the Continue reading

Black Friday Downtime: How to Avoid Impacts on Your Business

Hannah Culver Hannah is a solutions marketer at PagerDuty interested in how real-time urgent work plays out across all industries in this digital era. It’s a brisk Friday morning in November. You’re sipping your coffee and mentally preparing yourself for the day that’ll define your fiscal year. How will you fare this Black Friday? Are your teams prepared? We’ve all heard the 2020 Holiday Shopping Season Report, “The online holiday season exceeded $188B resulting in a strong growth rate of 32% over the 2019 season.” This trend didn’t start with COVID-19, however. A

Heavy Networking 596: Weaponizing Firewalls And Middleboxes For DDoS Attacks

Today's Heavy Networking podcast dives into academic research on DDoS attack techniques. Our guests have published a paper about how the TCP protocol and middleboxes such as firewalls can be weaponized by bad actors and used in reflective amplification attacks. We discuss technical details, how they performed this research, potential countermeasures, and more.

Heavy Networking 596: Weaponizing Firewalls And Middleboxes For DDoS Attacks

Today's Heavy Networking podcast dives into academic research on DDoS attack techniques. Our guests have published a paper about how the TCP protocol and middleboxes such as firewalls can be weaponized by bad actors and used in reflective amplification attacks. We discuss technical details, how they performed this research, potential countermeasures, and more.

The post Heavy Networking 596: Weaponizing Firewalls And Middleboxes For DDoS Attacks appeared first on Packet Pushers.

Video: Introduction to Network Addressing

A friend of mine pointed out this quote by John Shoch when I started preparing the Network Stack Addressing slide deck for my How Networks Really Work webinar:

The name of a resource indicates what we seek, an address indicates where it is, and a route tells us how to get there.

You might wonder when that document was written… it’s from January 1978. They got it absolutely right 42 years ago, and we completely messed it up in the meantime with the crazy ideas of making IP addresses resource identifiers.

Read more …

Video: Introduction to Network Addressing

A friend of mine pointed out this quote by John Shoch when I started preparing the Network Stack Addressing slide deck for my How Networks Really Work webinar:

The name of a resource indicates what we seek, an address indicates where it is, and a route tells us how to get there.

You might wonder when that document was written… it’s from January 1978. They got it absolutely right 42 years ago, and we completely messed it up in the meantime with the crazy ideas of making IP addresses resource identifiers.

Read more …

Quick Tunnels: Anytime, Anywhere

Quick Tunnels: Anytime, Anywhere
Quick Tunnels: Anytime, Anywhere

My name is Rishabh Bector, and this summer, I worked as a software engineering intern on the Cloudflare Tunnel team. One of the things I built was quick Tunnels and before departing for the summer, I wanted to write a blog post on how I developed this feature.

Over the years, our engineering team has worked hard to continually improve the underlying architecture through which we serve our Tunnels. However, the core use case has stayed largely the same. Users can implement Tunnel to establish an encrypted connection between their origin server and Cloudflare’s edge.

This connection is initiated by installing a lightweight daemon on your origin, to serve your traffic to the Internet without the need to poke holes in your firewall or create intricate access control lists. Though we’ve always centered around the idea of being a connector to Cloudflare, we’ve also made many enhancements behind the scenes to the way in which our connector operates.

Typically, users run into a few speed bumps before being able to use Cloudflare Tunnel. Before they can create or route a tunnel, users need to authenticate their unique token against a zone on their account. This means in order to simply Continue reading

Western Digital announces a hybrid hard drive

Western Digital has announced a new disk drive architecture that combines flash memory with high-density hard-disk drives plus a small CPU to manage everything.If this sounds familiar, it is. Several years ago there was an effort by WD and other hard-disk drive (HDD) makers to build hybrid hard drives, with small flash drives acting as a cache for the hard disk, but those efforts failed, said Ravi Pendekanti, senior vice president of HDD product management and marketing at WD.Now see how AI can boost data-center availability and efficiency “There was a huge pitfall in those [drives],” he told me. The drives didn’t know what kind of data they had, so they didn’t know that hot data was frequently accessed and should be written on to the flash drive, while warm or cold that wasn’t accessed as much should be written to the disk.To read this article in full, please click here

Western Digital announces a hybrid hard drive

Western Digital has announced a new disk drive architecture that combines flash memory with high-density hard-disk drives plus a small CPU to manage everything.If this sounds familiar, it is. Several years ago there was an effort by WD and other hard-disk drive (HDD) makers to build hybrid hard drives, with small flash drives acting as a cache for the hard disk, but those efforts failed, said Ravi Pendekanti, senior vice president of HDD product management and marketing at WD.Now see how AI can boost data-center availability and efficiency “There was a huge pitfall in those [drives],” he told me. The drives didn’t know what kind of data they had, so they didn’t know that hot data was frequently accessed and should be written on to the flash drive, while warm or cold that wasn’t accessed as much should be written to the disk.To read this article in full, please click here

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