Classless IP Addressing
In the beginning, classful addressing was a great idea for keeping IP addresses organized. But as the Internet grew, and IP addresses became scarce, classful addressing was found to be too limiting. Classless IP addressing, known as Inter-Domain Routing (CIDR) was released in September 1993. More ...
Network Gateways
When networks with different protocols, such as Ethernet and Token Ring need to be connected together, this requires reconstruction of the data packets. To do this, information from above the network layer is required. A gateway is a device that can function at all seven layers of the OSI model. More ...
IPv4 Datagram Fields
If you are pursuing CompTIA Network+ certification, of if you're involved in network troubleshooting, it's important to understand the construction of an IP datagram. More ...
Internet Protocol versions IPv4, IPv5 and IPv6
Internet Protocol is the part of the TCP/IP protocol that is responsible for addressing packets. IPv4 uses a 32-bit address IPv6 uses a 128-bit address. This article describes how IPv4 are converted to IPv6 addresses. More ...
Session Border Controllers - More Than Just a Voice Firewall
The migration from Time-Division Multiplexing to the more flexible IP based SIP networks brought an unexpected security challenge. Session Border Controllers focused primarily on SIP and H.323 session security. More ...
What is PPP, PPPoA and PPPoE?
PPP was designed to provide a connection between two devices. PPP comes with options including encryption, authentication and data compression. PPPoA is the standard for connection over an ADSL network. PPPoE is the standard for connection over an Ethernet network. More ...
Understanding IP Routing
The Transmission Control Protocol/Internet Protocol TCP/IP suite of protocols is the underlying technology for information exchange on the Internet. This essential reference shows you how to isolate and resolve common network failures and to sustain optimal network operation. More ...
OSI Network Model
The OSI model was developed years ago as a reference for network protocol and application designers to build their products with an open standard. That would promote a standard for developing network devices, interfaces, applications and services that would work together. It is a model rather than a specification since it defines layers and services for those layers and how each layer works with the layer above and below it. More ...
Introducing OpenStack
OpenStack is one of the most popular cloud computing management packages. OpenStack provides a common platform for controlling clouds of servers, storage, network, and even application resources. OpenStack is managed through a web-based interface, a command-line interface (CLI), and an application programming interface (API). More ...
The OSI Application Layer
This layer provides the interface between applications and the Network Operating System (NOS). The Application layer provides network services and applications such as HTTP, FTP, TELNET and SMP. More ...
Evolution of the Microsoft NOS (Active Directory)
A Network operating system (NOS0) is a networked environment in which resources, such as users, groups, and computers are stored in a central repository. Microsoft's first integrated NOS environment became available in 1990 with the release of Windows NT 3.0. More ...
TCP/IP Protocol Suite
A good portion of the knowledge required to be a network technician relates to the TCP/IP protocol suite. This article describes the most important protocols in the TCP/IP protocol suite. Many other less frequently used protocols exist. More ...
Basic TCP/IP Networking
In this article, I'm going to describe how a network works. I am NOT not going to load you down with details. Instead, I'm just going to describe what happens when you start your client computer. How it gets access to the network. More ...
IPv6 Prefix Length Notation
In IPv4, the prefix (or network portion) of the address can be identified by a dotted-decimal netmask, commonly referred to as a subnet mask. IPv6 address prefixes can be represented much the same way that IPv4 address prefixes are written in CIDR notation. More ...
Neighbor Discovery Protocol (NDP)
Neighbor Discovery Protocol is part of the new version of the Internet Protocol (IPv6). Its function is to resolve IPv6 addresses into valid MAC addresses. All addresses discovered by NDR are stored in a buffer known as the neighbor cache. More ...
