IEEE ICPADS / P2PNVE 2007: Kalman Graffi - ECHoP2P - Emergency Call Handling over Peer-to-Peer Overlays
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IEEE ICPADS / P2PNVE 2007: Kalman Graffi - ECHoP2P - Emergency Call Handling over Peer-to-Peer Overlays

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The impact of the peer-to-peer paradigm increases both in research and in industry. Still, serious applications for P2P-based systems are rare. On the other hand, Emergency Call Handling (ECH) is (or ...

The impact of the peer-to-peer paradigm increases both in research and in industry. Still, serious applications for P2P-based systems are rare. On the other hand, Emergency Call Handling (ECH) is (or will be) a mandatory function for VoIP services. In this paper we investigate international legal and technical requirements of ECH and present ECHoP2P, a solution that fulfills these requirements. Based on Globase.KOM and HiPNOS.KOM, ECHoP2P provides the functionality to determine the closest and (geographically) responsible Emergency Station to a calling peer. Further, Emergency Calls are processed with highest priority in the overlay, so that quality of service guarantees are given. We evaluated ECHoP2P thoroughly and present the quality and costs analysis, identified tradeoffs and effects of optimization parameters. ECHoP2P provides a fully evaluated solution for Emergency Call Handling and for further location-aware applications.

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  • 22 Minuten für alles, d.h. 15 Minuten Vortrag
  • Bootstrapping: just one zone, the whole world assigned to the first superpeer (Peers with high CPU power, with good network connection, and with a history of long online times, are marked as potential superpeer) Network grows: highly loaded areas clustered into rectangular zones using a clustering algorithm assigned to one peer (preferably to one in that area) Load of the peers… Next slide
  • Betrachten wir also Scheduling und Active Queue Management Verfahren. Was Active Queue Management ist, werde ich gleich beschreiben. Allgemein geht es darum, dass das System Anfragen an eine Ressource erhält und entscheiden muss, welchem Anfrager wann die Ressource zur Verfügung gestellt wird. Dieses Prinzip ist auf verschiedene Ressourcen anwendbar, wie z.B. Rechenkraft, Bandbreite oder Speicherzugriffe. Wir gehen davon aus, dass die Anfragen in einer Queue zwischengespeichert werden, währen die Ressource in Benutzung ist. Scheduling nennt man nun das Verfahren, dass bestimmt, welches der Anfrager aus der Queue als nächstes Zugriff auf die Ressource erhält, sie bestimmt also die Reihenfolge der Anfrager in der Queue. Die Referenzlösung dafür ist First-In-First-Out. Nun kann es vorkommen, dass die Queue des Systems an ihre Grenzen stößt, da auch sie nur endliche Länge hat. Für diesen Fall gibt es Verfahren, die man unter dem Sammelbegriff Active Queue Management zusammenfasst. Sie entscheiden welche Anfragen aus der Queue entfernt werden, wenn eine Überlast vorliegt. Typisches Beispiel für ein Active Queue Management Verfahren ist Drop Tail, dass alle neu ankommenden Verfahren bei Überlast verwirft. Wir sehen, dass die Scheduling und Active Queue Management Verfahren allgemein für die Ressourcennutzung anwendbar sind. Um nun aber tiefer in die Materie einzusteigen und zu erfahren welche Verfahren es gibt und wo ihre Vor- und Nachteile liegen, habe ich mich mit verschiedenen Lösungen auseinander gesetzt.

IEEE ICPADS / P2PNVE 2007: Kalman Graffi - ECHoP2P - Emergency Call Handling over Peer-to-Peer Overlays IEEE ICPADS / P2PNVE 2007: Kalman Graffi - ECHoP2P - Emergency Call Handling over Peer-to-Peer Overlays Presentation Transcript

  • ECHoP2P: Emergency Call Handling over Peer-to-Peer Overlays Kalman Graffi , Aleksandra Kovacevic, Kyra Wulffert, Ralf Steinmetz
  • Outline
    • Motivation
    • Legal and Technical Requirements
    • Solution: ECHoP2P
      • Globase.KOM: Location Based Search
        • SOS Area Search
        • SOS Jurisdiction Search
        • SOS Jurisdiction Search Extended
      • HiPNOS.KOM: QoS for Overlay Flows
    • Evaluation
    • Conclusion and Impact
  • Emergency Call Handling is Crucial
    • Observation:
    • VoIP telephony is replacing primary phone service
    • Emergency Call Service:
      • Core feature of (classic) telephone networks
      • Limited support by VoIP Providers
      • No support by any P2P Internet telephony network
    • End User License Agreement
    • „ No Emergency Calls: by entering into this Agreement You acknowledge and agree that the Skype Software does not and does not intend to support or carry emergency calls. “
  • Scalable all-IP based ECH needed: P2P can help!
    • Policies governing Voice over IP are rapidly evolving
      • Emergency Call Support becomes mandatory around the world
    • Network technologies are converging
      • Next Generation Networks
      • P2P over UMTS and GPRS/GSM
      •  All-IP paradigm
    • IP-based telephony requires Emergency Call Support !
      • P2P-based architecture is a good candidate
      • P2P solution can be applied on any IP enabled network
      • P2P systems: scalable, robust and load balanced (if done well)
  • Outline
    • Motivation
    • Legal and Technical Requirements
    • Solution: ECHoP2P
      • Globase.KOM: Location Based Search
        • SOS Area Search
        • SOS Jurisdiction Search
        • SOS Jurisdiction Search Extended
      • HiPNOS.KOM: QoS for Overlay Flows
    • Evaluation
    • Conclusion and Impact
  • Legal and technical requirements
    • Location critical service:
      • Routing: contact the closest or the responsible ES
    • Quality of service is crucial :
      • Emergency Calls are privileged user traffic
      • Contact the ES as soon as possible
      • In case of congestion: keep less relevant traffic back
    •  Can peer-to-peer systems fulfill these requirements?
    • Provision of the caller’s number for call backs and identification
    • (Fast) provision of the caller’s geographical position
    • Identification of the calling person (EU and Japan)
    • Provision of call back opportunities and call up keeping
    • Dispatching the call to ES responsible for the caller’s location
    • Highest delay priority for emergency calls: low delay bounds
    • Provision of stable communication even under network congestion
  • Outline
    • Motivation
    • Legal and Technical Requirements
    • Solution: ECHoP2P
      • Globase.KOM: Location Based Search
        • SOS Area Search
        • SOS Jurisdiction Search
        • SOS Jurisdiction Search Extended
      • HiPNOS.KOM: QoS for Overlay Flows
    • Evaluation
    • Conclusion and Impact
  • EC Routing: Implementation in Globase.KOM
    • Problem: Location-based search requirements
    • Solution: Globase.KOM - Geographical LOcation BAsed SEarch
      • More details:
        • IEEE P2P ’07
        • ACM Transactions on Multimedia ‘07
      • Developed for the requirements of location based services
      • A logical neighbour is a geographical neighbour
        • Like in CAN
        • But: Tree structure enables search/lookup in O(log N)
      • Extended with following search mechanisms:
        • Closest peer (Emergency Station ES)
        • Peer fulfilling a specific criteria (responsibility)
  • Globase.KOM: Geographical LOcation BAsed SEarch = peers = superpeers A B Lower bound L1 Upper bound L2 Superpeer load Split zone to reduce load I A B J D K E H G C F C D E F G H I J K
  • EC Routing: Implementation in GLOBASE.KOM
    • Problem: Which is the proper Emergency Station?
    • Solutions for GLOBASE.KOM:
    • SOS Area Search
      • Focus on neighboring peers to caller’s location
      • Find closest Emergency Station
    • SOS Jurisdiction Search
      • Emergency Stations with Coverage Area
      • Find responsible Emergency Services Station
  • Outline
    • Motivation
    • Legal and Technical Requirements
    • Solution: ECHoP2P
      • Globase.KOM: Location Based Search
        • SOS Area Search
        • SOS Jurisdiction Search
        • SOS Jurisdiction Search Extended
      • HiPNOS.KOM: QoS for Overlay Flows
    • Evaluation
    • Conclusion and Impact
  • Closest Emerg. Station: SOS Area Search r r new SOS O A B D E G H I SOS SOS SOS B C SOS H Emergency Stations G H Peer Super Peer Emergency station F J SOS G K
  • Responsible ES : SOS Jurisdiction Search SOS O A B D E G H I SOS SOS SOS C SOS I Emergency Stations I F SOS Peer Super Peer Emergency station Emergency st. coverage area J
  • Discussion to Presented Search Mech.
    • SOS Area Search:
      • Finds closest peer with attribute X (= Emerg. Station)
      • But only few (what if destroyed?)
    • SOS Jurisdiction Search
      • Finds (jurisdictionally) responsible peer
      • But only one (same problem)
    • List of close ES may be useful in catastrophe scenarios
    • Solution:
    • If responsible Emergency Station in not available, then contact the next closest Emergency Station
    •  SOS Jurisdiction Search Extended
  • List of ESs: SOS Jurisdiction Search Extended SOS O A B D E G H I SOS SOS SOS G C SOS H I Emergency Stations G H I F SOS Peer Super Peer Emergency station Emergency st. coverage area J
  • Outline
    • Motivation
    • Legal and Technical Requirements
    • Solution: ECHoP2P
      • Globase.KOM: Location Based Search
        • SOS Area Search
        • SOS Jurisdiction Search
        • SOS Jurisdiction Search Extended
      • HiPNOS.KOM: QoS for Overlay Flows
    • Evaluation
    • Conclusion and Impact
  • Scheduling and Active Queue Management
    • Mechanisms to provide QoS in network layer
      • Scheduling
        • Reorder tasks/messages in queue
        • Reference: First-in-First-Out
      • Active Queue Management
        • Active upon congestion of queue
        • Reference: Drop Tail
    • Mechanisms can be applied to various resources
    Resource Sched.+AQM 1. Message Scheduling Before: After: 2. Queue Management Before: After: Queue Limit
  • Overlay Bandwidth Management
    • Overlay bandwidth management
      • New layer Network Wrapper : API between overlay and underlay
      • Apply sched. and AQM to overlay flows
    • In [graffi07] we show:
      • Overlay flows: small and many
      • Stateless sched. and AQM needed
    Buffer management In-from overlay Insert msg in buffer Apply AQM mech. Timeout Pick next msg (SCHED) Out to underlay Bandwidth available? Receive message yes no
    • HiPNOS.KOM: Highest Priority First, No Starvation (IEEE LCN ’07)
      • Introduce (independent) message priorities
        • For loss – criticality (1 byte)
        • For delay – criticality (1 byte)
    • Active Queue Management solution:
      • If buffer size exceeded:
        • Drop message with lowest loss-prio.
    • Scheduling solution
      • If bandwidth available:
        • Pick message with highest latency-prio.
    • Avoid starvation
      • Periodically increase delay-prio. of queued messages
    HiPNOS.KOM: Sched. and AQM of Overlay Flows In-from overlay Insert msg in buffer Apply AQM mech. Timeout Pick next msg (SCHED) Out to underlay Bandwidth available? Receive message yes no
  • Outline
    • Motivation
    • Legal and Technical Requirements
    • Solution: ECHoP2P
      • Globase.KOM: Location Based Search
        • SOS Area Search
        • SOS Jurisdiction Search
        • SOS Jurisdiction Search Extended
      • HiPNOS.KOM: QoS for Overlay Flows
    • Evaluation
    • Conclusion and Impact
  • Evaluation: Simulation Scenarios
    • PeerfactSim.KOM :  P2P Systems Simulator
    •  www.PeerfactSim.com
    • General parameters
      • 10,000 peers
      • Without churn and failures
    • Built scenarios
      • SOS Area Search
      • SOS Jurisdiction Search
      • SOS Jurisdiction Search Extended
    • Metrics:
      • Operation duration
      • # of contacted peers
      • Distance to the closest found ES
      • Ratio of responsible ES
      • Message type distribution
    Alabama Emergency Zones. Source: NENA Alabama Density Population. Source: US census Snapshop of the simulated scenarios
  • Evaluation: Efficiency
    • • Operation duration
    • Compared to SOS Jurisdiction Search
      • SOS Jurisdiction Search Ext.
        • ~ 43% more efficient
      • SOS Area Search
        • ~ 28% more efficient
    • Contacted peers per operation
    • Compared to SOS Jurisdiction Search Ext.
      • SOS Jurisdiction Search
      • ~ 3 times less
      • SOS Area Search
        • ~ 2 times less
    SOS Calls Normalized Distribution Operation Duration [ms] SOS Calls Normalized Distribution Contacted Peers 10.000 peers Experiment size SOS search algorithms Scenarios Operation Duration Contacted peer Metrics
  • Evaluation: Efficiency
    • • Distance
    • Compared to SOS Jurisdiction Search
      • SOS Jurisdiction Search Ext.
        • ~ 13% more efficient
      • SOS Area Search
        • ~ 28% more efficient
    • Percentage of responsible ES
      • SOS Jurisdiction Search ~ 100%
      • SOS Jurisdiction Search Ext. ~ 25%
      • SOS Area Search ~ 21%
    Distance [pixel] Responsible ES [%] SOS Calls Normalized Distribution SOS Calls Normalized Distribution 10.000 peers Experiment size SOS search algorithms Scenarios Distance, Responsible ES % Metrics
  • Evaluation: Summary of Results not good / good / very good Yes No, if the responsible station collapses Yes, only few results Suitable for catastrophe scenarios? Yes Yes No, resp. areas needed Suitable for everyday emergency scenarios? 100% 100% 98% Successful operations High Low Medium Metric: # of results Medium High Low Metric: Distance to ES High Low Medium Cost: SOS traffic High Low Medium Cost: Contacted peers Low High Medium Cost: Operation time SOS Jurisdiction Search Extended SOS Jurisdiction Search SOS Area Search
  • Outline
    • Motivation
    • Legal and Technical Requirements
    • Solution: ECHoP2P
      • Globase.KOM: Location Based Search
        • SOS Area Search
        • SOS Jurisdiction Search
        • SOS Jurisdiction Search Extended
      • HiPNOS.KOM: QoS for Overlay Flows
    • Evaluation
    • Conclusion and Impact
  • Conclusion and Impact
    • Problem: Emergency Call Handling needed for P2P-based VoiP
    • ECHoP2P:
      • Built on
        • Globase.KOM: Geographical LOcation BAsed Search
        • HiPNOS.KOM: provides QoS to overlay flows
      • Presented protocols:
        • Search for the closest Emergency Station ES (Area Search)
        • Lookup the responsible ES (Jurisdiction Search)
        • Search for list of ES in the near (Jurisdiction Search Ext.)
    • Evaluation:
      • Solutions fulfill requirements for ECH in VoIP
      • Tradeoffs identified, application areas named
    • Impact:
      • “ Serious” P2P application presented
      • Need for QoS in P2P systems pointed out
  • Questions? Kalman Graffi Peer-to-Peer Research Group Dept. of Electrical Engineering and Information Technology Multimedia Communications Lab · KOM Merckstr. 25 · 64283 Darmstadt · Germany Phone (+49) 6151 – 16 49 59 Fax (+49) 6151 – 16 61 52 [email_address] Further information: http://www.KOM.tu-darmstadt.de/ Publications: http://www.KOM.tu-darmstadt.de/Research/Publications/publications.html