Network Configurations
Infrastructure Mode
This is the standard network configuration mode utilized for Wi-Fi® networks.
- Uses Access Points (AP).
- Nodes can only transmit to other nodes through the AP.
- AP fully supports all 802.11 network management functions and operations.
- Basic Service Set (BSS) aka cell in the Infrastructure mode contains:
- Access points
- Wireless hosts
- LAN connection (second PHY)
In a typical home access network, the AP function is combined with switch and router functionality in a single device, such as the Linksys E1200.
Ad-Hoc Mode
- No Access Points.
- Nodes can only transmit to other nodes within the link coverage.
- Nodes organize themselves into a network of peer-peer connections.
- Independent Basic Service Set (IBSS) aka cell in the Ad-Hoc mode contains:
- Wireless hosts only
- Distributed management
- Each station searches for an IBSS before starting its own (best practice – not mandated by 802.11).
- Each station takes turns transmitting the beacon for the IBSS.
- Each station applies security to communications.
Due to the computational/protocol overhead of current Wi-Fi security frameworks (i.e. WPA/2), most stations only implement WEP (the original 802.11 security framework) in Ad-Hoc mode. The WEP is known to be easily broken.
For this reason, 802.11 Ad-Hoc mode is not supported in some systems (for example, android). This has led to the development of alternative configurations for implementing point-point Wi-Fi communications, such as Wi-Fi Direct or SoftAP.