User manual
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Router 
A system responsible for making decisions about which of several paths network 
(or Internet) traffic will follow. To do this, it uses a routing protocol to gain 
information about the network and algorithms in order to choose the best route 
based on several criteria known as “routing metrics.” 
Subnet Mask 
A subnet mask, which may be a part of the TCP/IP information provided by your 
ISP, is a set of four numbers (e.g., 255.255.255.0) configured like an IP address. 
It is used to create IP address numbers used only within a particular network (as 
opposed to valid IP address numbers recognized by the Internet, which must be 
assigned by InterNIC). 
TCP/IP, UDP 
Transmission Control Protocol/Internet Protocol (TCP/IP) and Unreliable 
Datagram Protocol (UDP). TCP/IP is the standard protocol for data transmission 
over the Internet. Both TCP and UDP are transport layer protocols. TCP 
performs proper error detection and error recovery, and thus is reliable. UDP, on 
the other hand, is not reliable. They both run on top of the IP (Internet Protocol), 
a network layer protocol. 
VCI 
A virtual circuit identifier is part of the ATM cell header. A VCI is a tag indicating 
the channel over which a cell will travel. The VCI of a cell can be changed as it 
moves between switches via signaling. 
VPI 
A virtual path identifier is part of the ATM cell header. A VPI is a conduit for a 
number of virtual circuits. 
WAN 
A wide area network is a network that connects computers located in 
geographically separate areas (e.g., different buildings, cities, countries). The 
Internet is a wide area network. 
Web-based Management Graphical User Interface (GUI) 
Many devices support a graphical user interface that is based on the Web 
browser. This means the user can use the familiar Netscape or Microsoft Internet 
Explorer to control/configure or monitor the device being managed. 










