fir3net
June 11, 2017

How to Build an OpenStack Network using the OpenStack CLI

in OpenStack
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 segment traffic using a VLAN tag of 50. Figure 1 - Topology Components Before…

TUN, TAP and Veth - Virtual Networking Devices Explained

in Terms and Concepts
Computer systems typically consist of a (or set of) networking devices, i.e eth0, eth1 etc. These network devices are associated to a physical…

How to Install OpenDaylight

in How-Tos
OpenDaylight is an SDN controller provided by the Linux Foundation. In this article we will show you the steps required to perform a simple…

What is OpenFlow?

in Protocols
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…

What is SNI (Server Name Indication)?

in Concepts and Terminology
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…

Route Leaking within an MPLS Network

in Cisco
Introduction First of all, what is a route leak? A route leak is the propagation of routing announcement(s) beyond their intended scope - RFC7908…

How to Configure an L3 MPLS VPN on Cisco IOS

in Cisco
Introduction Within this article we will walk through the various steps required in configuring MPLS. NOTE This article does not look to explain the…
cisco_cef

What is CEF (Cisco Express Forwarding)?

in Cisco
Introduction Cisco Express Forwarding (CEF) is a packet-switching technique used within Cisco routers. The main purpose of CEF is to optimize the…

How to Write Clean Code

in Programming
Introduction Even bad code can function. But if code isn't clean, it can bring a development organization to its knees. Every year, countless hours…

Python - What are Context Managers?

in Python
What are Context Managers? Context managers are constructs that allow you to set something up and tear something down automatically, by using using…

Python - What are Static and Class Methods?

in Python
Have you ever seen some Python code and wondered what @staticmethod and @classmethod do ?In short, they are both methods that modify the default…

Python - What are Abstract Classes?

in Python
An abstract class can be considered a blueprint for other classes, allowing you to mandate a set of methods that must be created within any child…

Yum Error - Thread died in Berkeley DB library ... Error: rpmdb open failed)

in Linux
Issue When executing Yum you receive the following error, [root@william-gce blog]# yum install npm rpmdb: Thread/process 3934/139752225695488 failed:…

Python - What does Property() do ?

in Python
What is Property()? The purpose of this function is to create a property of a class. A property looks and acts like an ordinary attribute, except…

Cisco ASA - ICMP Inpsect and the Connection Table

in Cisco
Recently I've discovered that there is, well, fairly limited information online around this point. In this short article we will explain how ICMP…