Confederations By its true definition, a confederation is an organization which consists of a number of parties or groups united in an alliance or league. But what is a BGP confederation? BGP Confederation A BGP confederation is an alternative method to route reflectors, used to reduce the number of BGP peerings within a single AS. … Read more
What is ORF? Outbound Route Filtering (ORF) is a Cisco proprietary feature that prevents the unnecessary exchanging of routes that are subject to inbound filtering. This, in turn, minimizes bandwidth across the links and reduces CPU cycles upon the router during the processing of the neighbor UPDATE. ORF works by the router transmitting its inbound filters … Read more
BGP Path Selection Process BGP exchanges routes (prefixes) between BGP peers. Each of these announcements from a peer for a prefix is called a path. [1] The routes within these UPDATE messages are stored within the BGP Table and kept separate from the Routing Information Base (RIB). The BGP process then selects the “best” path from … Read more
Introduction When the BGP routing policy is amended the BGP neighbor session must be reset in order for the changes to take effect. Of course in a production environment performing a hard reset i.e clear ip bgp … , isn’t something that is recommended. Within this article, we will look at the various options available … Read more
Introduction Reverse path forwarding (RPF) is a technique used in modern routers for the purposes of ensuring loop-free forwarding of multicast packets in multicast routing and to help prevent IP address spoofing in unicast routing. [1] Within this article, we will look at multicast RPF, and look into why it is needed along with how it … Read more
BGP Messages Within BGP (as per RFC 1771) there are four BGP message types. They are, OPEN – Used to open a BGP communication session between peers. This is the first message sent by each side once the 3WHS is complete, and can be thought of as a HELLO. Only once each side has confirmed … Read more
Introduction With this article, we will look at the basic commands used within Cisco IOS to configure OSPF. Basic Configuration To initially configure OSPF, at a minimum, you must configure three things – process ID, router ID, and the network. Process ID – Defines the OSPF process ID that OSPF will run under. This is … Read more
Introduction In order for OSPF-enabled routers to exchange information, they must form an adjacency (relationship) with their neighbor. Within this article, we will look at the process and various steps involved (Figure 1). Requirements Before the OSPF router even starts to try and form an adjacency, OSPF must know/determine the following: Router ID – The … Read more
Introduction IGMP (Internet Group Management Protocol) is a Layer 3 protocol (IP protocol number 2) and is a key component (Figure 1) to IP multicast. The role of IGMP is to notify a local multicast router when a host wants to receive multicast traffic for a specific group. Figure 1 – Summary of Multicast Components. There are 3 versions … Read more
Introduction Within this article we will look at how to interact with a networking device (Cisco CSR) using the NETCONF protocol. To do so, we will use the Python module – ncclient. What is NETCONF First of all, What is NETCONF? NETCONF (NETwork CONFiguration) is a protocol defined by the IETF to “install, manipulate, and … Read more
Introduction Following on from our previous article around NETCONF and YANG, we will look at the RESTCONF protocol. As per RFC 8040 (RESTCONF Protocol), the IETF describes RESTCONF as, “an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF).” Protocol … Read more
TL;DR NETCONF/YANG provides a standardized way to programmatically update and modify the configuration of a network device. To break this down further. YANG is the modelling language that describes the configuration changes. Whereas NETCONF is the protocol that applies the changes to the relevant datastore (i.e running, saved etc) upon the device. Introduction Let us start … Read more
Introduction Within this tutorial we will use NETCONF and YANG to configure an interface upon a Cisco CSR router using a combination of Python and the BASH CLI. Furthermore we will use 2 main tools – Pyang and Pyangbind. Before we start lets have a quick overview on what these tools do, Pyang is a YANG … Read more
Introduction NFV is a term that has been around for a few years now. As vendors and the open source communities look to drive the adoption of NFV, a wave of new acronyms and buzzwords are spreading through the industry. Within this article we will look into the various NFV components (such as standards, platforms, … Read more
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
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 box@odl:~$ sudo apt-get update box@odl:~$ sudo apt-get install software-properties-common box@odl:~$ sudo apt-get install maven git unzip Install Java 1.8 {loadposition content_lock} box@odl:~$ sudo add-apt-repository ppa:webupd8team/java box@odl:~$ … Read more
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
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
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
Introduction Cisco Express Forwarding (CEF) is a packet-switching technique used within Cisco routers. The main purpose of CEF is to optimize the forwarding of packets and increase the packet switching speed. History Prior to CEF there were 2 methods for packet-switching – Process- Switching and Fast-Switching. Process-Switching The first method, process-switching is the oldest and … Read more
Here is our hand-picked selection of the best courses you can find online:
Cisco CCNA 200-301 Certification Gold Bootcamp
Complete Cyber Security Course – Network Security
Internet Security Deep Dive course
Python Pro Bootcamp
and our recommended certification practice exams:
AlphaPrep Practice Tests - Free Trial