| 
           
            | 
                General 
                  Networking TermsNetwork
 A network is a collection of computers, server devices, and 
                  communication devices connected together and capable of communication 
                  with one another through a transmission medium.
 InternetAn internet is any grouping of two or more networks connected 
                  by one or more internet routers.
 
 Network 
                  ServicesNetwork services are the capabilities that the network system 
                  delivers to users, such as print servers, file servers, and 
                  electronic mail.
 
 AddressesTransmitting information in a network system is made possible 
                  by an addressing scheme that identifies the sender and destination 
                  of the transmission, using network and node addresses. Data 
                  is transmitted toand from these addresses in the form of packets.
 
 Routing 
                  TableA routing table is maintained in each router. This table lists 
                  all networks and routers in the internet and enables routers 
                  to determine the most efficient route for each packet. The routing 
                  table serves as a logical map of
 the internet, specifying the address of the next router in the 
                  path to a given destination network and the distance in hops. 
                  The router uses the routing table to determine where and whether 
                  to forward a packet. Each router periodically broadcasts its 
                  routing table to other routers on each of its directly connected 
                  networks, enabling them to compare and update their own tables 
                  with the most recent record of connected networks and routes. 
                  In this way, routing tables are kept current as changes are 
                  made on the internet.
 
 HopA hop is a unit count between networks on the internet. A hop 
                  signifies “one router away.”
 NodeDevice on the network.
 TCP/IP 
                  Networking TermsFTP
 File Transfer Protocol gives users the ability to transfer files 
                  between IP hosts. It uses TCP to provide connection initiation 
                  and reliable data transfer.
 HostA computer with one or more uses that can act as an endpoint 
                  of communication if it has TCP/IP.
 ICMPInternet Control Message Protocol provides a means for intermediate 
                  gateways and hosts to communicate. There are several types of 
                  ICMP messages and they are used for several purposes including 
                  IP flow control, routing table correction and host availability.
  
                  IPInternet Protocol which routes the data.
 IP 
                  DatagramThe basic unit of the information passed across and IP Internet. 
                  It contains address information and data.
 PINGPacket InterNet Groper is a program which uses ICMP echo request 
                  message to check if the specific IP address is accessible from 
                  the current host.
 
 PortA Destination point used by transport level protocols to distinguish 
                  among multiple destinations within a given host computer.
 
 SubNet 
                  AddressAn extension of the IP addressing scheme which enables an IP 
                  site to use a single IP address for multiple physical networks. 
                  Subnetting is applicable when a network grows beyond the number 
                  of hosts allowed for the IP address class of the site.
 
 TCPTransmission Control Protocol ensures reliable, sequential, 
                  delivery of data. TCP at each end of the connection ensures 
                  that the data is delivered to the application accurately, sequential, 
                  completely and free of duplicates. The application passes a 
                  stream of bytes to TCP which breaks it into pieces, adds a header, 
                  forming a segment, and then passes each segment to IP for transmission.
 
 TelnetThe TCP/IP standard protocol for remote terminal connection 
                  service. A user can telnet from the local host to a host at 
                  a remote site.
 
 UDPUser Datagram Protocol provides simple, efficient protocol which 
                  is connectionless and thus unreliable. The IP address contained 
                  in the UDP header is used to direct the datagram to a specific 
                  destination host.
 
 Well-Known 
                  PortAny set of port numbers reserved for specific uses vy transport 
                  level protocols (TCP & UDP). Well-known ports exist for 
                  echo servers, time servers, telnet and FTP servers.
 Communication 
                  Link DefinitionsSynchronous Serial Interfaces
 A serial interface between two devices which provides for bi-directional 
                  data transfer as well as clocking. One device, the DCE, provides 
                  the transmit and the receive timing to the second device, the 
                  DTE.
 Data 
                  Communication Equipment (DCE)This interfaces to the communication service’s transmission/reception 
                  medium, and includes T1 Voice/Data Multiplexors, 64/56 Kilobit 
                  DSU/ CSUs, and Fiber Optic Modems. The DCE provides the transmit 
                  and
 receive data pathways, along with their synchronous clocking 
                  signals, that are used by the Engage Router’s DTE interface 
                  for full duplex communication between the remotely interconnected 
                  networks.
 
 Data 
                  Terminal Equipment (DTE)This equipment, such as an Engage Router, attaches to the terminal 
                  side of Data Communication Equipment.
 
 Data 
                  Carrier Detect (DCD)A signal that indicates to the DTE that the DCE is receiving 
                  a signal from a remote DCE.
 
 Data 
                  Terminal Ready (DTR)Prepares the DCE to be connected to the phone line, then the 
                  connection can be established by dialing. Enables the DCE to 
                  answer an incoming call on a switched line.
 |  |  |  |