1. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST MadWifi-ath5k Usage Example Jongryool Kim 2010.01.05 Networked Media Laboratory School of Information & Mechatronics Gwangju Institute of Science & Technology http://netmedia.gist.ac.kr

2. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST Madwifi Multiband Atheros Driver Wireless Fidelity Net80211 Stack It is available in source code format Contains all functionalities of IEEE 802.11 protocol HAL (hardware abstraction layer) It is available in binary form only All the access to the hardware is governed by HAL Public interfaces hal/ah.h Ath Layer Defines Atheros specific callbacks Call net80211 stack for exploiting 802.11 functionalities Call HAL to communicate with the hardware

3. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST HAL (Hardware abstraction layer) Closed source module of Mad-Wifi (a complied binary) Although some understanding can be derived about its functions, no modifications to this module HAL performs some transmit and receive functions Setting a maximum limit on the allowable transmit power Handling some beacon management functions, some interrupt, and cache handling functions Providing control over selection of modes Chip reset function http://madwifi-project.org/wiki/DevDocs/HAL-usage

4. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST Madwifi-ath5k FOSS Linux driver for Atheros wireless card Call hardware functions directly. Based on MadWifi and OpenHAL Supported modes: mesh STA, station mode, Ad Hoc mode, (except Access point mode) http://madwifi-project.org/wiki/About/ath5k Functionalities control retransmission limit counts change backoff counts to any values disable backoff (FreeMAC) access directly hardware register value Etc.

5. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST Madwifi-ath5k structure overview base.c, base.h, hw.c, hw.h, phy.c: contain functions (responsible for the transmission of packets, reception of packets, driver initialization, and other hardware functionalities.) ath5k.h: define structure of the HAL & contains setting of driver (transmission rate, reception status, and driver mode) reg.h: holds the values for the hardware registers of Atheros xxx cards. initvals.c: fills in the registers in the wireless care with initial values. debug.c debug.h

6. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST Congestion-Aware Rate Adaptation in Wireless Networks: A Measurement- Driven Approach (P. A. K. Acharya, etc.) @ SECON’ 08 Measurement-driven rate adaptation scheme for 802.11 devices that uses the congestion measurement to identify congestion related packet losses. Develop a congestion measurement technique to identify congestion in real-time Design and implement rate-adaptation scheme by using the congestion measurement (rate decision depends on losses due to poor link quality) To measure the channel busy time ath5k of MadWifi driver for Atheros AR5212 chipset. 32-bit register counter to track “medium busy time” and “cycle time” “cycle time” counter is incremented at every clock tick “medium busy time” counter represents the number of clock ticks for which the medium was sensed busy. The ratio of “medium busy time” and “cycle time” counters gives the fraction of time during which channel is busy. Medium utilization fraction: during given interval, sum of time to transmit all data, management, control frames and necessary MAC delay for each frame. 1

7. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST Spectrum Agile Radios Project Report (Ji Woong Lee,etc.) [UCB] Development of channel selection algorithm, selection of platform and prototyping the proof of concept. Statistics collection Ath5k driver has direct access to the hardware register value ( func. ath5k_hw_reg_read() ) AR5k_PROFCNT_RXCLR: amount of time that the communication channel is busy) AR5K_PROFCNT_CYCLE: total time that elapsed)

8. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST Contention in Multi-hop wireless networks: model and fairness analysis (Vinay Kolay,etc.) @ MSWIM’09 Mitigate contention unfairness by observing neighborhood contention and adapt CW min Choice of contention metric for link X (C(X)): Recall: Contention unfairness happens when the source node observes long busy periods and channel-gaps. Starvation indicators: Average wait time to transmit one packet (Wt ). Number of channel-gaps observed (Gn). Observation: While Wt is sucient, Wt :Gn converges faster. Protocol details Each node maintains neighborhood contention info (Contention Information Table). Node piggybacks CW min and C(X) periodically. Node adapts its CW min : Increment if the link has the lowest contention information. Decrement if the link is the most starved member. Avoid oscillations. Update using Additive Increase Additive Decrease (AIAD) method Multiplicative increase/decrease causes excessive short-term unfairness and longer convergence times. To allow flexibility in adjusting the low level MAC parameters like CW min this team will use a MadWifi-ath5k (FreeMAC: Framework for Multi-Channel MAC Development on 802.11 Hardware (Ashish Sharma, etc.) @SIGCOMM PRESTO’08)

9. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST WiFIX: A new solution for 802.11-based wireless mesh network (Rui Campos, etc) @ CRC 2009 WiFIX (Wi-Fi Network Infrastructure eXtension) based on 802.1D bridge and a single message protocol. Using 802.1D bridge’s simple learning mechanism for frame forwarding It is based on a single-message protocol that enables the self-organization of the WMN. To remove 802.11s proactive mechanisms For using 802.11s -> ath5k (Ubuntu 9.04, wireless card is an atheros WR50G)

10. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST Development of a Gateway to control and connect an Itinerant wireless sensor network with a central system via internet (2009) Implementation of wireless sensor networks on trains to monitoring temperature and vibration measurements in the wheels of trains. Ath5k : it is the driver needed for wireless mini-PCI adapter. Atheros 5354MP PLUS ARIES2 wireless Mini-PCI adapter (802.11 a/b/g)

11. Networked Media Lab. D EPT. OF I NFO. & Mech., GIST Conclusion Many researcher uses and will use MadWifi-ath5k for research There are new wireless chipset supported by Madwifi-ath5k (no Madiwifi) Therefore, we need to use and check the functionality and features of MadWifi-ath5k