Context-aware Adaptive Routing for Delay Tolerant Networking

1
Context-aware Adaptive Routing for Delay Tolerant
Networking

• Mirco Musolesi
• Joint work with Cecilia Mascolo
• Department of Computer Science
• University College London
• Delay Tolerant Networks Research Group Meeting
• 65th IETF Meeting - Dallas, 23 March 2006

2
Outline of this Talk

• Overview of the Context-aware Adaptive Routing
  (CAR) protocol
• Extension to hybrid networks
• Integration with the DTN reference implementation
• Current research directions

3
Context-aware Adaptive Routing (CAR)

• Routing protocol for delay tolerant networks
  initially designed for delay tolerant mobile ad
  hoc networks
• Extension to hybrid networks, where some nodes
  are fixed or act as gateways for interconnecting
  different regions
• Context-aware routing designed for scenarios
  where
• Deterministic routing information is not
  available
• No geographical information (like GPS
  coordinates) are available

Adaptive Routing for Intermittently Connected
Mobile Ad Hoc Networks Mirco Musolesi, Stephen
Hailes and Cecilia Mascolo In Proceedings of 6th
IEEE International Symposium on a World of
Wireless, Mobile and Multimedia Networks
(WoWMoM'05). Taormina, Italy. June 2005.
4
Overview of the Protocol

• Based on host(s) acting as carrier(s) for
  asynchronous delivery of messages to hosts that
  can be
• Final recipient of the message/bundle
• Gateways between regions (fixed or mobile, such
  as mobile sinks)
• Choice of the best carrier(s) based on the
  evaluation of the context information
• Host colocation
• Host mobility
• Battery level

5
The Novelty of Our Approach

• Novelty of our approach store-and-forward
  decisions based on the prediction of the
  evolution of the DTN scenario
• In particular, we use Time Series Analysis based
  on State Space Models (Kalman Filter) to keep
  history into account and to predict the evolution
  of DTN scenarios

6
Asynchronous Delivery An Example
B
P
A
M
R
D
E
N
F
L
I
Q
H
O
7
Calculation of the Host Utility

• Host utility calculated using multi-criteria
  decision theory
• A utility is associated to each context attribute
  (i.e., a utility associated to host colocation
• Utilities are then composed using a weighted
  functions

8
Calculation of the Host Utility

• We tested the algorithm considering two
  attributes
• Colocation with a certain host (that may be the
  final recipient of the message or a gateway)
• Change degree of connectivity

9
Kalman Filter Prediction

• Very lightweight
• Only information about the current state must be
  maintained
• Suitable for resource-constrained devices
• No learning phase is necessary
• Fast convergence of the filter
• Different prediction models (considering trends
  and seasonal/periodic behavior)

10
Context-aware Adaptive Routing Protocol

• Host utilities are calculated by each host and
  are sent to the others together with the routing
  tables (in our implementation DSDV)
• Based on local calculations
• Adaptive refresh interval based on the context
  variability
• If the carrier of the message gets in reach with
  a host that can guarantee a better delivery
  probability, the message is transferred to that
  host

11
Predictability of Context Information

• Key issue for CAR predictability of context
  information
• Forecasting model cannot provide accurate
  predictions due to the inherent characteristics
  of the time series (for example randomness)
• Design of an autonomic component that is able at
  runtime to analyze the predictability of the time
  series of the context information
• If context information is not predictable,
  alternative routing strategies can be adopted
• Intelligent epidemic routing

Evaluating Context Information Predictability for
Autonomic Communication Mirco Musolesi and
Cecilia Mascolo In Proceedings of 2nd IEEE
Workshop on Autonomic Communications and
Computing (ACC'06). Niagara Falls, NY. June 2006.
To appear.
12
Integration of CAR in the DTN Reference
Implementation

• Implementation in the DTN2 reference
  implementation in process (testing phase)
• Porting to resource-constrained devices
• Integration of DTN reference implementation in a
  hybrid environment
• DTN reference implementation for gateways?
• Integration with other DTN systems for
  constrained devices (Bluetooth equipped mobile
  phones, sensor networks).

13
CAR Implementation in DTN2
14
CAR for Multi-Regions DTNs

• Based on deterministic and probabilistic
  mechanisms
• For example a server connected to the Internet
  has delivery probability equal to 1 for the smtp
  domain.
• Message ferries will have a delivery probability
  equal to 1 to hosts that are on their pre-defined
  paths
• Host utilities used to measure
• The probability of delivering message to the
  recipients of the message for intra-region
  communication
• the probability of delivering messages to
  gateways (or sinks in sensor networks) for
  inter-regions communication
• Deployed on heterogeneous devices mobile phones
  and WiFi APs (in progress), sensor networks
  (planned)

15
Our Current Research Directions

• Implementation of a system based on CAR for
  inter-regions communications
• CAR for sensor networks with mobile sinks
• Porting of DTN for Contiki (SICS, Sweden)
• Content based routing based on CAR
• Design of realistic mobility models
• based on social networks theory
• validated using real traces

SCAR Context-aware Adaptive Routing in Delay
Tolerant Mobile Sensor Networks Cecilia Mascolo
and Mirco Musolesi CS-UCL Research Note. January
2006.Submitted for Publication.
16
Questions?

• Adaptive Routing for Intermittently Connected
  Mobile Ad Hoc Networks
• Mirco Musolesi, Stephen Hailes and Cecilia
  Mascolo
• In Proceedings of 6th IEEE International
  Symposium on a World of Wireless, Mobile and
  Multimedia Networks (WoWMoM'05). Taormina, Italy.
  June 2005
• Evaluating Context Information Predictability for
  Autonomic Communication
• Mirco Musolesi and Cecilia Mascolo
• In Proceedings of 2nd IEEE Workshop on Autonomic
  Communications and Computing (ACC'06). Niagara
  Falls, NY. June 2006. To appear.
• SCAR Context-aware Adaptive Routing in Delay
  Tolerant Mobile Sensor Networks
• Cecilia Mascolo and Mirco Musolesi
• CS-UCL Research Note. January 2006.Submitted for
  Publication.
• Mirco Musolesi
• Department of Computer Science University College
  London
• m.musolesi_at_cs.ucl.ac.uk http//www.cs.ucl.ac.u
  k/staff/m.musolesi