A Simple Description of the IPv6 Header and Datagram
This article provides a simple description of the IPv6 header and datagram without a lot referring back to IPv4. More ...
Network Operating Systems
The purpose of a network is to permit users share resources located on other computers and to share peripheral devices such as printers. A network operating system (NOS) is specialized systems software designed to provide networking functionality. 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 ...
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 ...
TCP/IP Utilities
TCP/IP comes with a set of command line utilities that a network technician can use to manage and troubleshoot a network. PING is used to test the ability of two hosts on a network to communicate. More ...
IPv6 Flow Label Field
The IPv6 Flow Label field is used to help identify all the packets within the same flow to ensure that all the packets receive the same type of handling by the IPv6 routers. 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 ...
IP Addressing
The IP protocol uses a 32-bit address to define the network segment address and the node address. If the device is to be connected to the Internet, the address needs to be unique among all other devices connected to the Internet. More ...
WAN Network Protocols - DSL, SONET, HDLC, DWDM, DLSW+
This article discusses some of the most implemented Wide Area Networking (WAN) protocols in enterprise networking environments today including HDLC, DSL, SONET, DWDM, and DLSW+. HDLC is a Cisco proprietary protocol for designed for sending data across serial links. More ...
IPv6 Packet Fragmentation
Unlike in IPv4, an IPv6 router does not fragment a packet unless it is the source of the packet. The fields used in the IPv4 header for fragmentation do not exist in the IPv6 header. More ...
The OSI Network Layer
The Network layer (OSI layer 3) uses routable protocols to deliver data packets to networks connected through routers. Routing is the process of moving data packets from one network or network segment to another. More ...
The OSI Reference Model
No real world network operating systems conform exactly to the OSI model, but it is useful as a reference when describing existing systems. It is difficult to study network devices such as routers, switches, and gateways without using the model. More ...
T-Carrier
T-carrier is a time-division multiplexed (TDM) digital signal that has been used by the telephone companies for many decades. 24 8-bit signals are time-division multiplexed into a 1.544 Mbps t-carrier signal. More ...
Networking Protocols, Ports, Standards, and Organizations What Does it All Mean?
A protocol is a set of rules that devices agree to. A port is specific electronic connection, or software interface a protocol uses. A standard is a specification that the characteristics of the protocol's signal and the design of the interface. Networking standards are developed by networking standards organizations. More ...
OSI Transport Layer
The Transport layer (OSI layer 4) uses connection-oriented protocols to provide a reliable end-to-end connection between the source computer and the destination computer. Transmission Control Protocol (TCP) is a transport layer protocol. More ...
