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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 Most likey there will be a time (for one reason or another) where you need to insert a number of spaces to a set of lines within a text file.Within this short article we will show you how via the use of VIM. Steps 1. Within VIM select blockwise visual mode, by pressing CTRL-V.2. … 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