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WiFiRe LAN Emulation

WiFiRe LAN Emulation. Single Sector, 1 BS, multiple ST and clients Single proxy server to handle web and VoIP requests All machines connected using 802.3 or 802.11 based LAN MAC code in user space with Ethernet Sockets. TestBed Setup. To Internet. proxy. BS. switch. ST-1. ST-2. switch.

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WiFiRe LAN Emulation

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  1. WiFiRe LAN Emulation • Single Sector, 1 BS, multiple ST and clients • Single proxy server to handle web and VoIP requests • All machines connected using 802.3 or 802.11 based LAN • MAC code in user space with Ethernet Sockets

  2. TestBed Setup To Internet proxy BS switch ST-1 ST-2 switch switch client-1 client-2 client-3 client-4

  3. TestBed (cont.)‏

  4. Ethernet sockets • Using PF_SOCK in C • Byte level access • Binding with particular NIC • Send/receive data using sockets on MAC layer • Allows non-Ethernet packets (like WiFiRe frame); Eth switch broadcast those packets

  5. Beacon, Registration etc. • BS sends periodic beacons • ST sends registration request • BS adds ST in list, allow access • ST starts transmission • client can not start communication before registration • BS and ST shut down/ restart condition handled

  6. Beacon, Registration etc. ST sends request

  7. Encapsulation and Fragmentation • ST will receive packets from client, keep them in buffer • Encapsulate multiple MAC packets and make packets of 1450 bytes • Fragment MAC packets if larger • Takes care of Ethernet MTU • see next slide

  8. Encapsulation and Fragmentation ST collects packet and send them in single frame to BS

  9. Communication using 802.11 • Ethernet socket replaced with WiFi socket • Works with pseudo interface • Using madwifi driver • Transparent to BS/ST code • Client can be connected via wired/wireless LAN

  10. Communication with 802.11 Able to send / receive packets on 802.11 TCP session using 802.11

  11. GPSS and GPC mode • Grant per Subscriber station model followed • BS gives slots per ST • ST handles client level fairness • SSID, CID on ST level • GPC mode – work in progress

  12. Web and VoIP connectivity • Proxy machine runs squid server for web traffic • Asterisk server for VoIP connectivity • Clients send request to proxy using WiFiRe MAC protocol • Client --> ST --> BS --> proxy • Proxy replies back • Proxy --> BS --> ST --> Client

  13. Work in Progress • Basic Scheduler • Traffic Diversion at BS • Soft timer and ST synchronisation • DL-MAP and UL-MAP for GPC • Generic MAC PDU

  14. WiFiRe LAN Emulation Demo • at CEWiT, IITM • ?

  15. Assumption from IIT-M PHY board • Give feedback to MAC about PHY characteristic (like modulation, bandwidth, timeslot, sync issue etc. )‏ • Able to send / receive packet on given time slot (for example: send 1000 bytes at t=50)‏ • Synchronisation among sectors (6 PHY issue)‏ • Understand Ethernet packets • Buffer for bigger packets

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