An RPC (Remote Procedure Call) is a technique used in computer science that allows an application to contact a separate application or service within the same hard drive or on a remote location. While the application initiating the call is known as the “client,” the application or location that is being called is referred to as the “server.” RPC is very popular and is used as a basic framework for several networking systems. For example, RPC is used in print spoolers for communication between a computer and a printer, fax Read More

Domain Name System (DNS) is an Internet Engineering Task Force (IETF) standard name service which enables applications and users to connect to hosts in TCP/IP based networks by specifying a name. DNS makes it possible to assign domain names to organizations independent of the routing of the numerical IP address. DNS is a hierarchically distributed database that creates hierarchical names that can be resolved to IP addresses. The IP addresses are then resolved to MAC addresses. DNS therefore provides the means for naming IP hosts, and for locating IP hosts when they are queried for Read More

Windows Server 2003 and Windows XP support the following PPP authentication protocols: PAP or Password Authentication Protocol The oldest forms of authentication schemes used where the user credential are sent in plain text. This is not the securest form of passing authentication credentials as anybody can use a third party sniffer program and capture these clear text username and password as they are unencrypted. The next thing that would happens is the news of a server being compromised due to intruder attack. Avoid using PAP as much as you can. Read More

Windows and other operating systems have a WiFi signal strength meter, but this is usually basic software and does not really tell the user much about the wireless signal. Fortunately, there are many other programs that do the same thing, but show the user more details about the wireless connection. We will describe some of these programs. Net Stumbler Net Stumbler does several things. It is a wireless signal strength meter that gives detailed reports to the user about the wireless network. Net Stumbler also provides the user with a Read More

A codec (Coder/Decoder) converts analog signals to a digital bitstream, and another identical codec at the far end of the communication converts the digital bitstream back into an analog signal. In the VoIP world, codecs are used to encode voice for transmission across IP networks. Codecs for VoIP use are also referred to as vocoders, for "voice encoders". Codecs generally provide a compression capability to save network bandwidth. Some codecs also support silence suppression, where silence is not encoded or transmitted. Codec Algorithm Bit Rate (Kbps) Comments ITU G.711 PCM Read More

Symmetric Digital Subscriber Line (SDSL) is a kind of one kind of Digital Subscriber Line (DSL) used to provide high-speed Internet connectivity. Symmetric DSL is called “symmetrical” because the upstream and downstream connections have the same bandwidth. SDSL maintains the same high speed in both directions while working over the existing “twisted-pair” cables that exist in all telephone equipment. SDSL requires only one pair of copper wires to support a connection. These wires may reach as long as 3 kilometers. How SDSL Differs from ADSL Unlike the much more common Read More

Users can connect to a Linksys router manually by attaching an Ethernet cable from the router to a computer and typing 192.168.1.1 (the default IP address)  in the web browser. This kind of connection is used to setup a router for the first time or troubleshoot problems when a wireless connection is not available. By default, the username and password are “admin” and “password” respectively, but can be changed once the user is logged into the Linksys interface. How to Wirelessly Connect to a Linksys Router Under normal circumstances, you Read More

QSIG is a signaling protocol that is  based on ISDN. It communicates signals between private branch exchanges (PBXs) within a Private Integrated Services Network (PISN) using the application-level ROSE and connection-level Q9.31 protocols. QSIG uses ISDN as the physical link layer in the exchanges and is often used in enterprise voice or integrated service networks. The Q reference point that the protocol derives its name from is the formal dividing or demarcation point between two PINXs (Private Integrated Network Exchanges). Who Invented the QSIG Protocol? ECMA International first created the Read More

RADIUS (Remote Authentication Dial In User Service), defined in RFC 2865, is a protocol for remote user authentication and accounting. RADIUS enables centralized management of authentication data, such as usernames and passwords. When a user attempts to login to a RADIUS client, such as a router, the router send the authentication request to the RADIUS server. The communication between the RADIUS client and the RADIUS server are authenticated and encrypted through the use of a shared secret, which is not transmitted over the network. The RADIUS server may store the Read More

Multi-mode fiber is a type of fiber optic cable which is thick enough for light to follow several paths through the code. Multi-mode fiber is best suited for use in short lengths, such as those used in Local Area Networks (LANs) and Storage Area Networks (SANs). Multi-mode fiber comes in two standard widths, 62.5 micron and 50 micron. A micron is one millionth of a meter. 62.5 micron multi-mode fiber can support Gigabit Ethernet over distances as long as 275 meters; 50 micron multi-mode fiber can increase that range to Read More