Using this setting you specify the format used by the packet capture function to store the WLAN-specific information in the capture file.
The selection of the appropriate capture format depends on the transmission standard in your WLAN network and the scope of the information that you would like to capture. The IEEE 802.11 standard with its numerous extensions has grown over many years. However, the capture formats that were developed in parallel are not flexible enough to cater optimally for every extension (particularly 802.11n). For this reason there is no universal capture format which is equally suitable for all standards. However, there are recommendations that cover a wide spectrum of standards: Radiotap and PPI.
- SNMP ID:
- 2.12.86.1
- Console path:
- Setup > WLAN > Packet-Capture
- Possible values:
- Radiotap
- Uses the radiotap header. Radiotap is a widely accepted format on Linux and BSD WLAN drivers which enables the creation of compact captures due to its flexible structure. With radiotap you can record a large amount of WLAN-specific information with a high compression rate. This also applies to data packets from 802.11n compliant connections. Limitations only arise when recording antenna-specific RSSI and signal strength as well as aggregations (A-MPDU). If you do not require detailed WLAN-specific information for this, choose the PPI format instead.
- AVS
- Uses the AVS header. The AVS header is a newer development of the PRISM header, and is used by LCOS as the standard header up to version 8.60. However, since AVS is also unable to process information from 802.11n compliant connections, you should choose the more powerful radiotap header.
- PPI
- Uses the Wireshark proprietary PPI header. Use this setting if you want to analyze the capture file with Wireshark. PPI offers similar functions as radiotap but can also bypass its limitations on the recording of information about 802.11n compliant connections. A disadvantage to radiotap is, however, the weaker compression and less detailed header structure.
- PRISM
- Uses the classic PRISM header. Only use this setting if you want to analyze the capture file with a program which does not support any of the other formats. PRISM is not suitable for recording information from 802.11n compliant connections. In the meantime this is considered obsolete and should no longer be used.
- Plain
- Disables all headers. Use this setting if you are only interested in the packet data itself.
- Default:
- Radiotap
