ATP: Autonomous Transport Protocol

Transcription

1 ATP: Autonomous Transport Protocol Tamer Elsayed,, Mohamed Hussein, Moustafa Youssef,, Tamer Nadeem, Adel Youssef and Liviu Iftode Department of Computer Science University of Maryland, USA

2 Tracking in Sensor Networks Camera range Src Connection Establishment 2 3. Destination Migration To conserve energy, target is tracked using only one camera Data is transmitted through a streaming application (Src to a mobile command center (Dst Active camera changes as target moves (streaming application migrates Cannot tolerate data loss during camera change 1 Dst

3 What is ATP? Autonomous Transport Protocol Why autonomous? Decoupled from physical network Decoupled from the physical location of application endpoints Provides reliable communication between mobile endpoints

4 Features I Application-specific naming Connection endpoints are defined as contents in the P2P network Dynamic endpoints relocation on different end hosts without disrupting the connection ATP is responsible for forwarding segments to the destination and acknowledgments to the source regardless of their current location

5 Features II Reliable transmission between users not end-hosts Established connections maintained independent of intermediate node availability TCP-like interface Easy to write new ATP-aware applications Current applications can be made ATP-aware with minor modification

6 System Architecture Application Autonomous Trasnport Protocol Instance-Based Network P2P Lookup Service Underlying Network Mobile applications TCP-like interface Reliable transmission over IBN Transparent mobility Network of contents Location-independent independent addressing Communication infrastructure IP/MANET

7 Content-Based Network (CBN Network of endpoint entities Contents Active Contents communicates together by messages performs a lookup for other contents e.g. application service, network connection agent,.. Passive Contents stored in the network e.g. document,.. Location-independent independent addressing Extends P2P lookup services (e.g. CAN, Chord,.. Maps a content to a specific node

8 IBN=CBN++ Allows different instances of same content Instance Publishing Self (active / Free (passive Reliable Leased Instance Routing Decoupled from instance physical location Routes to specific or closest instance Replicates contents for fault-tolerance tolerance Caches info for future queries

9 IBN Routing Example User X:2,0 X:0,1 X:3,6 User X:2,3 IBN X:4,0 X:3,1 X:1,8 Published file User request Query request Query response

10 ATP over IBN IBN Content/Instance Addressing Contents are the communication endpoints Instances are agents working on behalf of mobile entities AS:i : ATP agent for the source S with index i Index i means the agent is responsible for sending packets starting from sequence number i

11 Source Migration Scenario Src Dst Node 1 Node 3 Publish (AS:0 Publish (D: (D:0, Data 1 (D:0, Data 2 (AS:1,Ack 1 (AS:2,Ack 2 Src Migrate( (D:0,Data 3 Node 2 (AS:3,Ack Land ( Publish (AS:4... (D:0,Data 4 (D:0,Data 5 (AS:4,Ack 4 (AS:5,Ack 5...

12 Design Issues Reclaiming Network Resources Enforcing a lifetime or using a leasing mechanism for publishing in the IBN Acknowledgement Mechanism Cumulative vs Range Acks Fault tolerance Relies on IBN route discovery service and/or on ATP mechanism to alleviate the node failure and link failure problems Security How to handle privacy, authenticity, and trust? End-to to-end Semantics Shifts the burden of waiting from the source endpoint which allows the source to terminate earlier.

13 Related Work TCP over Mobile IP TCP Connection Migration I3 Mobile Tapestry Shortcomings User is bound to a single host during connection lifetime Communication endpoints must exist simultaneously

14 Current Status Implemented a Java prototype of the ATP protocol over Pastry The prototype is deployed over a set of independent nodes at University of Maryland. A simple ATP-aware application runs on each node of the network Simulation in progress Further information