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Projects Overview Andrea Forte

Projects Overview Andrea Forte. Fast L3 handoff Passive DAD (pDAD) Cooperative Roaming (CR) Highly congested IEEE 802.11 networks – Measurements and Analysis. Fast L3 Handoff. We optimize the IP address acquisition time as follows: Subnet Discovery Checking Cache for a valid IP

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Projects Overview Andrea Forte

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  1. Projects Overview Andrea Forte • Fast L3 handoff • Passive DAD (pDAD) • Cooperative Roaming (CR) • Highly congested IEEE 802.11 networks – Measurements and Analysis 2005-2006

  2. Fast L3 Handoff • We optimize the IP address acquisition time as follows: • Subnet Discovery • Checking Cache for a valid IP • Temp_IP (Cache miss) The client “picks” a candidate IP using particular heuristics. • SIP re-invite The CN will update its sessionwith the TEMP_IP. • Normal DHCP procedure to acquire the final IP • SIP re-invite  The CN will update its session with the final IP. 2005-2006

  3. Fast L3 Handoff - Results 2005-2006

  4. IP MAC Expire Client ID MAC IP1 MAC1 570 DUID1 MAC1 IP2 MAC2 580 DUID2 MAC2 IP3 MAC3 590 DUID3 MAC3 Flag IP Client ID Passive DAD - Architecture DHCP server Address Usage Collector (AUC) • AUC builds DUID:MAC pair table (DHCP traffic only). • AUC builds IP:MAC pair table (broadcast and ARP traffic). • The AUC sends a packet to the DHCP server when: • a new pair IP:MAC is added to the table • a potential duplicate address has been detected • a potential unauthorized IP has been detected • DHCP server checks if the pair is correct or not and it records the IP address as in use. (DHCP has the final decision!) TCP Connection Broadcast-ARP-DHCP Router/Relay Agent SUBNET 2005-2006

  5. Cooperative Roaming (CR) • Stations can cooperate and share information about the network (topology, services). • Stations can cooperate and help each other in common tasks such as IP address acquisition. • Stations can help each other during the authentication process without sharing sensitive information, maintaining privacy and security. • Stations can also cooperate for application-layer mobility and load balancing. 2005-2006

  6. CR – Results (1/2) 2005-2006

  7. CR – Results (2/2) 2005-2006

  8. Wireless measurements in highly congested 802.11 networks • IETF meeting in Dallas (IETF-65) • Three days of measurements (~8GB of data). • 400~500 people in one room (plenary). • IEEE 802.11a/b • Multiple APs on same channel. • Congestion analysis (throughput, retries, ARF), handoff analysis (Apple vs. others), unusual behaviors (broadcast feedback), load balancing (num. of clients vs. bandwidth). 2005-2006

  9. Projects OverviewKundan Singh • P2P-SIP using external DHT • Thread and event models • Conference server scalability 2005-2006

  10. SIP-using-P2PP2P-SIP using an external distributed hash table (DHT) • Data vs service modes • Data: treat DHT as data storage using put/get/remove • Service: join DHT to provide registrar/presence service using join/leave/lookup • Logical operations • Contact management • put (user id, signed contact) • Cryptographic key storage • User certificates and private configurations • Presence • put (subscribee id, signed encrypted subscriber id) • Composition needs service model • Offline message • put (recipient, signed encrypted message) • NAT and firewall traversal • STUN and TURN server discovery needs service model Proposed an XML-based data format 2005-2006

  11. SIP-using-P2PImplementation in SIPc with the help of Xiaotao Wu • OpenDHT • Trusted nodes • Robust • Fast enough (<1s) • Identity protection • Certificate-based • SIP id == email • P2P for Calls, IM, presence, offline message, STUN server discovery and name search • P2P clients better than proxies: • Less DHT calls • OpenDHT quota for fairness imposes limit on proxies Should this be made open source? 2005-2006

  12. SIP proxy performanceEffect of software architecture and multi-processor hardware Both Pentium and Sparc took approx 2 MHz CPU cycles per call/s on single-processor Calls/s for stateless proxy, UDP, no DNS, 6 msg/call Better performance as this includes mempool changes Calls/s for stateful proxy, UDP, no DNS, 8 msg/call Software architecture further improves performance: S3P3 can support 16 million BHCA 2005-2006

  13. Should sipd use 2-stage thread pool architecture? Not much concurrency in stateful mode: needs more investigation 2005-2006

  14. SIP conference server PerformanceFor G.711 audio mixing on a 3 GHz Pentium 4 with 1 GB memory • About 480 participants in a single conference with one active speaker (CPU is bottleneck) • About 40 four-party conferences, each with one active speaker (CPU is bottleneck) • Memory usage: 20 kB/participant • Mixer delay: less than 20 ms • Increasing the packetization interval to 40 ms improves performance to 700 participants, but also increases mixer delay • Both Pentium and Sparc take about 6 MHz/participant 2005-2006

  15. Cascaded conference server SIP REFER message is used to create cascading       I measured the CPU usage for two cascaded servers: supports about 1000 participants in a single conference. The cascaded architecture scales to tens of thousands of participants. 2005-2006

  16. Projects OverviewXiaotao Wu • CUTE (Columbia University Telecommunication service Editor) • GUI-based service creation tool to help inexperienced users to create services • Service learning and service management • Service learning • Service risk management • Handling feature interactions 2005-2006

  17. CUTE (Columbia University Telecommunication service Editor) 2005-2006

  18. Survey on CUTE • Evaluating how likely an end user can create telecommunication services by himself and how useful and friendly CUTE is • http://www.surveymonkey.com/s.asp?u=909901973365 2005-2006

  19. Service learning and service risks • Causal relationship between call information and call decisions • Decision tree induction • Incremental Tree Induction algorithm • Service risk management • Identify: Lose connection, privacy, money, attention • Analyze: Possibility, impact, overall risk • Resolve: Change communication methods, transfer, reduce overall risk • Contingency plan 2005-2006

  20. Feature interaction handling • Tree merging Incoming call Incoming call Incoming call If time is between 10:00AM and 11:00AM If address is hgs If address is hgs If time is between 10:00AM and 11:00AM = + accept accept accept reject Forward to conf Forward to conf reject Take actions from both scripts. Simply setting precedence rules cannot work. 2005-2006

  21. Service management 2005-2006

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