There are two methods of wireless networking:
Method |
Description |
Ad Hoc |
An ad hoc network works in peer-to-peer mode. The wireless NICs in each host communicate directly with one another. An ad hoc network:
You will typically only use an ad hoc network to create a direct, temporary connection between two hosts. |
Infrastructure |
An infrastructure wireless network employs an access point (AP) that functions like a hub on an Ethernet network. With an infrastructure network:
You should implement an infrastructure network for all but the smallest of wireless networks. |
The following diagram shows a sample enterprise wireless network operating in infrastructure mode:
The various components of a wireless network are described in the following table.
Component |
Description |
Station (STA) |
An STA is a wireless network card (NIC) in an end device such as a laptop or wireless PDA. STA often refers to the device itself, not just the network card. |
Access Point (AP) |
An access point (AP), sometimes called a wireless access point, is the device that coordinates all communications between wireless devices as well as the connection to the wired network. It acts as a hub on the wireless side and a bridge on the wired side. It also synchronizes the stations within a network to minimize collisions. |
Basic Service Set (BSS) |
A BSS, also called a cell, is the smallest unit of a wireless network. All devices in the BSS can communicate with each other. The devices in the BSS depend on the operating mode:
|
Independent Basic Service Set (IBSS) |
An IBSS is a set of STAs configured in ad hoc mode. |
Extended Service Set (ESS) |
An ESS consists of multiple BSSs with a distribution system (DS). The graphic above is an example of an ESS. |
Distribution System (DS) |
The distribution system (DS) is the backbone or LAN that connects multiple APs (and BSSs) together. The DS allows wireless clients to communicate with the wired network and with wireless clients in other cells. |
Wireless networks use the following for identification:
Identifier |
Description |
Service Set Identifier (SSID) |
The Service Set Identifier (SSID), also called the network name, groups wireless devices together into the same logical network.
Note: Using BSS ID to describe the SSID of a BSS is technically incorrect. |
Basic Service Set Identifier (BSSID) |
The BSSID is a 48-bit value that identifies an AP in an infrastructure network or a STP in an ad hoc network. The BSSID allows devices to find a specific AP within an ESS that has multiple access points, and is used by STAs to keep track of APs when roaming between BSSs. Note: Do not confuse the BSSID with the SSID. They are not the same thing. |
Credit: Testout 640-802 CCNA Notes
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