I don’t like to correct my friends in public, but if someone says “I still believe that flow-based technologies will exceed the capabilities of packet-based technologies” (see Network Break 53), it’s time to revisit the networking fundamentals.
According to Wikipedia (but what do they know…):
Read more ...When using open-source network simulators that use KVM as a virtualization tool, each node in the network simulation is actually a KVM virtual machine so the maximum supported number of nodes in a network simulation is the same as the maximum number of KVM virtual machines that can run on the host computer.
Unfortunately, there seems to be no single authoritative statement about the maximum number of KVM virtual machines that can run on a host computer. Most information I could find about KVM limits does not publish absolute limits but, instead, recommends best practices.
In this post, I will synthesize the information available from many different sources into a single recommendation for the maximum number of KVM-based nodes that can run in an open-source network simulator running on a single host computer.
The goal of this article is to introduce a script that automates a process of collecting MAC and IP address of hosts connected to Cisco switches using Simple Network Management Protocol (SNMP). We will configure SNMP version 2c and 3 on Cisco switches and create a BASH script that collects required data for us. For this purpose I have created a test network lab using GNS3. The topology consists of three Cisco virtual switch appliances running vIOS-L2 and one network management station (NMS) based on Kali Linux. Network hosts are simulated by Core Linux appliances connected to Cisco vIOS-l2 switches.
1. GNS3 Lab
1.1 List of software used for creating GNS3 lab
1.2 Network Topology Description
All virtual network and host devices are running inside GNS3 project and they are emulated by Qemu emulator and virtualizer. The only exception is a Cisco Catalyst 3550 switch that is connected to topology via GNS3 network Continue reading
Talking with Martin Casado on the Future of Networking. Its all about the applications.
The post Show 265: Future Of Networking: Martin Casado appeared first on Packet Pushers.
Talking with Martin Casado on the Future of Networking. Its all about the applications.
The post Show 265: Future Of Networking: Martin Casado appeared first on Packet Pushers.
This post explains how to set up a keyboard layout the way I like it. It may not fit you at all, but it may give you ideas that would work for you.
In short: I remap Caps Lock to add some extra keys.
First a description of what my preferred keyboard layout is: I type Dvorak, but also want to occasionally use Swedish letters. There are a couple of Dvorak versions for Swedish, but since most of my typing is in English or programming I think they compromise too much on the accessibility of other keys to add these three Swedish characters.
So for decade or so I’ve been remapping Caps Lock to AltGr and holding down AltGr to add new keys. Typing “ö” quickly became fluent and easy, since it involves holding down one key with my left hand and pressing a key with another.
I used this method even before I switched to Dvorak, because if you’ve ever coded on a Swedish keyboard you should know how terrible it is. I know several Swedish programmers who use US keyboard layout all the time because of this, and simply live without being able to type proper Swedish.
This post explains how to set up a keyboard layout the way I like it. It may not fit you at all, but it may give you ideas that would work for you.
In short: I remap Caps Lock to add some extra keys.
First a description of what my preferred keyboard layout is: I type Dvorak, but also want to occasionally use Swedish letters. There are a couple of Dvorak versions for Swedish, but since most of my typing is in English or programming I think they compromise too much on the accessibility of other keys to add these three Swedish characters.
So for decade or so I’ve been remapping Caps Lock to AltGr and holding down AltGr to add new keys. Typing “ö” quickly became fluent and easy, since it involves holding down one key with my left hand and pressing a key with another.
I used this method even before I switched to Dvorak, because if you’ve ever coded on a Swedish keyboard you should know how terrible it is. I know several Swedish programmers who use US keyboard layout all the time because of this, and simply live without being able to type proper Swedish.
This is just notes in case I need to do this again. It’s for my QPov project.
sudo apt-get install autoconf libboost-all-dev libjpeg-dev libtiff-dev libpng-dev
git clone https://github.com/POV-Ray/povray.git
cd povray
git checkout --track -b 3.7-stable origin/3.7-stable
cd unix
./prebuild.sh
cd ..
./configure --prefix=$HOME/opt/povray COMPILED_BY="My_Name on RPi"
make
make install
This is just notes in case I need to do this again. It’s for my QPov project.
sudo apt-get install autoconf libboost-all-dev libjpeg-dev libtiff-dev libpng-dev
git clone https://github.com/POV-Ray/povray.git
cd povray
git checkout --track -b 3.7-stable origin/3.7-stable
cd unix
./prebuild.sh
cd ..
./configure --prefix=$HOME/opt/povray COMPILED_BY="My_Name on RPi"
make
make install
This morning my wife was trying to purchase something from BELK.com. She ran into an issue at the point of transaction. The error that was being returned looked like the credit card number was invalid. Since the first attempt was on a mobile device, she attempted the transaction again from a computer. This was met with the same challenge. Ultimately, three different credit cards were attempted and none seemed to work. After reviewing the card account activity, I could see a total of about 5 authorizations against the 3 cards.
My wife contacted BELK by phone and they asked us to call our cc company (which I begrudgingly did). Finally they were able to process the cart transaction manually and admitted that we weren’t the only people experiencing the problem. They went on to say that their systems were very slow and that they were having issues with transactions internally too.
Continue reading
Hey, it's HighScalability time:
Netronome, Xilinx, and others are playing with the 'OpenFlow 2.0' language.
Please join us in congratulating the following iPexpert students who have passed their CCIE lab!
You might be familiar with the idea of using BGP as an SDN tool that pushes forwarding entries into routing and forwarding tables of individual devices, allowing you to build hop-by-hop path across the network (more details in Packet Pushers podcast with Petr Lapukhov).
Researchers from University of Louvain, ETH Zürich and Princeton figured out how to use OSPF to get the same job done and called their approach Fibbing. For more details, listen to Episode 45 of Software Gone Wild podcast with Laurent Vanbever (one of the authors), visit the project web site, or download the source code.
