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 ...
IPv6 Dynamic Address Allocation
As with IPv4, IPv6 addresses can be statically assigned. However, when it comes to dynamic addressing, IPv6 has a different approach. IPv6 uses the ICMPv6 Router Advertisement message to suggest to devices how to obtain their IPv6 addressing information. More ...
The OSI Data Link Layer
The Data Link layer uses MAC addresses is to pass data frames from the Physical layer to the Network layer and vice versa. The use of MAC addresses permits the direction of data within the same network, but not across routers. More ...
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 ...
14 Common Network Ports You Should Know
Ports are virtual software-based and are managed by a computer's operating system. Different types of data flow to and from a computer over the same network connection. The use of ports informs computers what to do with the data they receive. Each port is assigned a number, and each is associated with a specific process or service. Port numbers are standardized, most reserved for certain protocols, for example, all HTTP messages go to port 80. More ...
Free eBook: Introduction to 802.11 Wireless
The growth of wireless mobile devices is incredible. If you're an IT professional you'll need to understand wireless technology. This free ebook by Aaron Balchunas explains everything from radio frequency to wireless authentication protocols. More ...
DSL (Digital Subscriber Line)
DSL (Digital Subscriber Line) is a technology used to transmit digital data over telephone lines. DSL service can be transmitted simultaneously with voice band telephone service on the same line because DSL uses a much higher frequency that rides on top of the low 3400 Hz voiceband. More ...
Unicast, Multicast, Broadcast. What Does It Mean?
Unicast, Multicast, and Broadcast are different network transmission methods. Unicast is a transmission between a single sender and a single receiver, while Broadcast is a transmission from a single sender to all clients on the network. More ...
Representation of IPv6 Addresses
IPv6 addresses are 128 bits in length and written as a string of hexadecimal digits. At first glance, these addresses can look overwhelming. RFC 2373 and RFC 5952 provide two helpful rules for reducing the notation involved in the standard format. 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 ...
IPv4 Address Classes
Originally, IP network numbers were defined with rigid boundaries and grouped into address classes. Even though address classes was created to facilitate efficient use of the IPv4 address space, because of its rigidity it has been abandoned for more flexible classless addressing. More ...
Networking Routing Believability and Administrative Distance
If a network is running more than one routing protocol and a router receives two route advertisements from different routing protocols, which route advertisement does the router believe?. More ...
IPv6 Neighbor Discovery Protocol (NDP)
Neighbor Discovery Protocol (NDP) is used by IPv6 hosts for Router Discovery, Neighbor Discovery and Duplicate Address Discovery. More ...
Comparing IPv4 and IPv6 at a Glance
When examining the details of the IPv4 and IPv6 headers, there are some important differences between the two protocols. This article summarizes some of the differences. 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 ...
