The way that most services work under TCP/IP is that the server is configured to use a well known port number and the client connects from a random high port. Most of these well known ports are port numbers below 1,024. High ports are ports 1,024 or above. In the old days, ports below 1,024 …
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 …
Multimedia Messaging Service (MMS) is an upgraded version of the SMS (Short Messaging Service) through which users can send and receive multimedia messages such as texts, pictures, video clips, audio clips, etc. with any compatible cell phone. It is an advanced messaging service that lets users send multiple media in one single message to one …
Digital Subscriber Line or Digital Subscriber Loop (DSL) is a type of high-speed Internet technology that enables transmission of digital data via the wires of a telephone network. DSL does not interfere with the telephone line; the same line can be used for both Internet and regular telephone services. The download speed of DSL ranges …
PPP (Point-to-Point Protocol) is the most widely used method for transporting IP packets over a serial link between the user and the Internet Service Provider (ISP). Although PPP is primarily used over dialup lines, variants such as PPoE (PPP over Ethernet) and PPoA (PPP over ATM) extend PPP to new data-link layer protocols. PPP was …
CSMA/CD (Carrier Sense Multiple Access / Collision Detection) is the protocol used in Ethernet networks to ensure that only one network node is transmitting on the network wire at any one time. Carrier Sense means that every Ethernet device listens to the Ethernet wire before it attempts to transmit. If the Ethernet device senses that …
The ARP cache is a table that stores mappings between Data Link Layer addresses and Network Layer addresses. The Data Link Layer addresses are usually MAC addresses and the Network Layer addresses are most frequently IP addresses. The Operating System stores the ARP cache in RAM. Displaying the ARP Cache Under most Unix and Microsoft …
IPX/SPX is a protocol suite that is implemented on many corporate internetworks. IPX/SPX was developed to operate in Novell Netware in LAN environment. But today, the IPX/SPX is also used in Microsoft NT, Microsoft XP and Lotus Notes environment along with Vista. IPX/SPX on Cisco IOS The Cisco IOS also provides a wide range of …
A subnet mask allows users to identify which part of an IP address is reserved for the network and which part is available for host use. By looking at the IP address alone, especially now with classless inter-domain routing, users cannot tell which part of the address is which. Adding the subnet mask or netmask …
The Physical Layer is the lowest layer in the OSI (Open Systems Interconnection) Model of computer networking and is used to transfer electrical signals that represent data from one place to another. While the Physical Layer does not represent data itself, it does provide a means for that data to move. Essentially, the Physical Layer …