User's Manual
Chapt er 6: Glossary
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Chapt er 6 : Glossary
ARP (Addre ss Re solut ion Prot ocol )
ARP is a TCP/ I P prot ocol for m apping an I P address t o a physical m achine address t hat is
recognized in the local net w ork, such as an Et hernet address.
A host wishing to obt ain a physical address broadcasts an ARP request ont o t he TCP/ I P
netw ork. The host on t he net work that has t he I P address in t he request t hen replies wit h
its physical hardware address.
I nverse ARP ( I n- ARP), on the ot her hand, is used by a host to discover it s I P address. I n
this case, t he host broadcasts it s physical address and a RARP server replies with the host's
I P address.
DH CP ( D ynam ic H ost Configura tion Pr ot ocol)
When operates as a DHCP server, t he ADSL Router assign I P addresses t o t he client PCs on
the LAN. The client PCs “ leases” these Privat e I P addresses for a user- defined am ount of
tim e. After t he lease t ime expires, t he privat e I P address is m ade available for assigning to
other network devices.
The DHCP I P address can be a single, fixed public I P address, an I SP assigned public I P
address, or a privat e I P address.
I f you enable DHCP server on a private I P address, a public I P address will have to be
assigned t o t he NAT I P address, and NAT has to be enabled so t hat t he DHCP I P address
can be t ranslated into a public I P address. By this, the client PCs are able t o access t he
I nt ernet.
LAN ( Local Are a N et w ork ) & W AN ( W ide Are a N et w or k)
A LAN is a com put er net work lim ited t o t he im m ediate area, usually t he sam e building or
floor of a building. A WAN, on t he other hand, is an outside connect ion t o another network
or t he I nt ernet .
The Ethernet side of t he ADSL Rout er is called t he LAN port . I t is a twist ed- pair Ethernet
10Base-T int erface. A hub can be connected t o the LAN port . More t han one com puters,
such as server or print er, can be connect ed through t his hub t o the ADSL Rout er and
com poses a LAN.
The DSL port of the ADSL Router com poses the WAN int erface, which supports PPP or RFC
1483 connect ing t o anot her rem ote DSL device.
N AT ( N et w ork Addr ess Tr an slat ion ) I P Addr ess
NAT is an I nt ernet standard that translates a privat e I P within one net work t o a public I P
address, either a static or dynam ic one. NAT provides a type of firewall by hiding int ernal I P
addresses. I t also enables a com pany t o use m ore int ernal I P addresses.
I f t he I P addresses given by your I SP are not enough for each PC on the LAN and t he ADSL
Rout er, you need to use NAT. With NAT, you m ake up a private I P net work for the LAN and
assign an I P address from t hat network t o each PC. One of som e public addresses is