N/W ( Tutorials I )

What Is LAN

LAN is a computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. A system of LANs connected in this way is called a wide-area network (WAN). Most LANs connect workstations and personal computers. Each node (individual computer) in a LAN has its own CPU with which it executes programs, but it also is able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as data. Users can also use the LAN to communicate with each other, by sending e-mail or engaging in chat sessions.

Term Protocol

Protocol is a standard way of communicating across a network. A protocol is the "language" of the network. It is a method by which two dissimilar systems can communicate. TCP is a protocol which runs over a network.

FTP (File Transfer Protocol)

FTP is File Transfer Protocol. It used to exchange files on the internet. To enable the data transfer FTP uses TCP/IP, FTP is most commonly used to upload and download files from the internet. FTP can be invoked from the command prompt or some graphical user interface. FTP also allows to update (delete, rename, move, and copy) files at a server. It uses a reserved port no 21.

What is multicasting

Multicasting allows a single message to be sent to a group of recipients. Emailing, teleconferencing, are examples of multicasting. It uses the network infrastructure and standards to send messages.

Functionality Of PING

Ping Is particularly used to check if the system is in network or not. It also gives packet lost information. In windows ping command is written as ping ip_address. The output returns the data packets information. The number of packets sent, received and lost is returned by PING.

MAC Address

A Media Access Control address is a unique identifier that is assigned to the network adapters or NICs by the manufacturers for the purpose of identification and used in the Media Access Control protocol sub layer. It is a 12 digit hexadecimal number. A MAC address usually encodes the registered identification of the manufacturer, if the address is assigned by the manufacturer. It some times also called as Ethernet Hardware Address / physical address/ adapter address.

Spanning-Tree protocols

Spanning Trees are a standard technique implemented in LAN connections. On a mesh topology, a set of spanning tree algorithms were developed for prevention of redundant transmission of data along intermediate hops between a source and a destination host. In the absence of spanning trees, a mesh network is flooded and rendered unusable by messages by circulating within a loop that is infinite, between hosts. An algorithm used in transparent bridges which determines the best path from source to destination to avoid bridge loops.

At the time of STP initialization in a network, its first action is to utilize the Spanning Tree Algorithm for selection of a root bridge and a root port. The root bridge is the network which has lowest-value bridge identifier. All the switches on the network use Bridge Protocol Data Units to broadcast the bridge IDs to the other switches in that network. Soon after selection of the root bridge, determination of the root ports on all other bridges is done.