We feature technical articles across the entire IT spectrum - CCNA networking, security, operating systems, cloud, and programming.

Interface to Network Security Functions (I2NSF)

Interface to Network Security Functions (I2NSF) is a working group within the IETF formed to define a set of interfaces and data models for monitoring and managing network security functions hosted across multiple sites. I2NSF states, Network security functions (NSFs) are provided and consumed in increasingly diverse environments. Users of NSFs could consume network security … Read more

What is MacVTap?

Definition MacVTap is a Linux device driver, based upon the combination of – Macvlan and TAP (descriptions below), that allows for the creation of virtual (tap-like) interfaces. Each virtual network interface is assigned its own MAC and IP address, then attached to the physical interface (also know as the lower interface), Macvlan – Linux kernel … Read more

The Journey of a Frame through a Linux Based System

Abstract The scope of this article is to describe, at a high level, the journey a frame takes through a Linux based system. NOTE This article does not cover Linux kernel performance issues and caveats, for more information around this please see pushing the limits of kernel networking. Ingress Lets first look at the path … Read more

How to Build an OpenStack Network using the OpenStack CLI

  Introduction Within this article we will detail the steps required to build a simple Neutron networking topology using the OpenStack CLI. Topology Our topology (Figure 1) will consist of an L3 router, an external network, a tenant network and a range of floating IPs. Our external network will be a VLAN based network and … Read more

What is the Difference between Apt-get Upgrade and Update?

The other day I asked myself, What is the difference between apt-get update and apt-get upgrade? As I’m sure many other people, at some point may ask the same, I thought I would share the answer. Quite simply, apt-get update – updates the list of available packages, and their versions. However it does NOT upgrade … Read more

How to Install OpenDaylight

OpenDaylight is an SDN controller provided by the Linux Foundation. In this article we will show you the steps required to perform a simple installation upon Ubuntu. Install Binaries [email protected]:~$ sudo apt-get update [email protected]:~$ sudo apt-get install software-properties-common [email protected]:~$ sudo apt-get install maven git unzip Install Java 1.8 {loadposition content_lock} [email protected]:~$ sudo add-apt-repository ppa:webupd8team/java [email protected]:~$ … Read more

What is OpenFlow?

What is OpenFlow? OpenFlow is a protocol, released by the ONF that allows the remote modification of a network switch’s forwarding table. In other words, the control plane is decoupled from the forwarding plane, enabling network controllers to define the flow of traffic between switches far greater than standard routing or forwarding protocols. Figure 1. … Read more

What is SNI (Server Name Indication)?

What is SNI? SNI (Server Name Indication) is an extension to the TLS protocol, that provides the ability to host multiple HTTPS-enabled sites on a single IP. How does it work? Prior to SNI the client (i.e browser) would send the requested hostname to the webserver within the HTTPS payload (Figure 1). Due to the … Read more

Route Leaking within an MPLS Network

Introduction First of all, what is a route leak? A route leak is the propagation of routing announcement(s) beyond their intended scope – RFC7908 Within this article we will look at 2 methods of route leaking within an MPLS environment – static routes and route maps. To demonstrate both methods we will look at 2 … Read more

How to Configure an L3 MPLS VPN on Cisco IOS

Introduction Within this article we will walk through the various steps required in configuring MPLS. NOTE This article does not look to explain the various terms and concepts of MPLS, for details around these please see Getting to Know MPLS. Overview Within our example we will have 2 customers COSTA and STARBUCKS. Each customer consisting … Read more