What is representing those terms ?
ADHOC
In ad hoc mode, also known as Independent Basic Service Set (IBSS) or peer-to-peer mode, all of the computers and workstations connected with a wireless NIC card can communicate with each other via radio waves without an access point.
Ad hoc mode is convenient for quickly setting up a wireless network in a meeting room, hotel conference center, or anywhere else sufficient wired infrastructure does not exist.
INFRASTRUCTURE
Infrastructure Mode In infrastructure mode, all mobile and wireless client devices and computers communicate with the access point, which provides the connection from the wireless radio frequency world to the hard-wired LAN world. The access point performs the conversion of 802.11 packets to 802.3 Ethernet LAN packets
Data packets traveling from the LAN to a wireless client are converted by the access point into radio signals and transmitted out into the environment. All wireless clients and devices within range can receive the packets, but only those clients with the appropriate destination address will receive and process the packets. A basic wireless infrastructure with a single access point is called a Basic Service Set (BSS).
When more than one access point is connected to a network to form a single sub-network, it is called an Extended Service Set (ESS). The 802.11 specification includes roaming capabilities that allow a client computer to roam among multiple access points on different channels. Thus, roaming client computers with weak signals can associate themselves with other access points with stronger signals. Alternately, by setting up multiple access points to cover the same geographic area and by using different non-overlapping frequencies,
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