This document discusses delay tolerant streaming services for transmitting live video from mobile devices over unstable mobile ad-hoc networks. It motivates the need for such services when conventional network infrastructure is unavailable. The approach involves building an adaptive overlay network on top of the mobile ad-hoc network to enable delayed and disrupted video streaming. Several technical challenges are outlined and initial results are highlighted from experiments and simulations evaluating the feasibility of video streaming over mobile ad-hoc networks formed by mobile phones. Future work is discussed around developing a prototype system and exploring fundamental changes needed to support emerging applications and technologies.

1. Delay Tolerant Streaming Services
Thomas Plagemann
on behalf of the DT-Stream Team

2. Motivation
Using head mounted
Streaming live video
camera
Mobile Ad-Hoc Network
3

3. Motivation (cont.)
• Communication to CCC using head mounted
cameras
• Networking infrastructure might not be available
è use mobile phones to establish wireless ad-hoc
network
• Problem: mobile, unstable, partitioned network
• Opportunity: video can also be useful when it arrives
late
4

4. Motivation (cont.) This is a
mock-up
5

5. History and Funding
• Pre-project in 2008 at UiO
– 4 Master students
– Collaboration with University of Oviedo (Spain)
• Verdikt funding: 3 PhDs & 1 PostDoc (2008 – 2012)
• University of Oviedo funding: 1 PhD
6

6. Technical Challenges
• Mobile wireless space – how to be always
best connected?
• Mobile phones have resource restrictions and
therefore the network they create
– Network topology awareness
– Cross-layer optimization
– Simulation tools not appropriate
7

7. The Mobile Wireless Space
High
“Relative Mobility”
Space/Time Paths
Hybrid Environments
No (Space/Time)
Paths
Space Paths
Low
High Node Density Low
8

8. The Overall Approach
• Adaptive Overlay for Delay Tolerant
Streaming
DT-S DT-S DT-S
DT-S
overlay
3 7
5
1 8 Mobile
Ad-hoc
2 4 6
Network

9. A few Results Highlighted
• Early results used to focus the research:
– Survey of video streaming over MANETs
– Real world experiments
• Recent results:
– Modeling mobile nodes in network simulators
– Systematic cross-layer optimization
– At home in heterogeneous networks
– Non-intrusive network clustering
10

10. Video Streaming over MANETs
• M. Lindeberg, S. Kristiansen, T. Plagemann, V. Goebel:
“Challenges and techniques for video streaming over mobile ad
hoc networks”, Multimedia Systems Journal, 2010
– Over 100 papers analyzed
11

11. Real World Experiments
• Kristiansen, S., Lindeberg, M., Rodríguez-Fernández, D.,
Plagemann, T.: “On the Forwarding Capability of Mobile
Handhelds for Video Streaming over MANETs”, ACM
MobiHeld 2010 at ACM SIGCOMM 2010, August 2010
Monitor
2.2 GHz Intel Centrino Duo Core Bomb shelter
2 GB RAM
M
S R
Sender
Receiver
2.6 GHz Intel Centrino Duo Core
2.6 GHz Intel Centrino Duo core
3 GB RAM
F 3 GB RAM
Forwarder
Nokia N900 Take away points:
Mobile phones are a bottleneck
Introduce non-neglect able delay
12
Severe at saturation point

12. Real World vs. Simulation
Nokia N900
13

13. Towards realistic simulation
Network Simulator Execution Model
Traffi 3
c
SrvA SrvB Execute Progress Processing Stages
Scheduler
Threads Update Simulator
Program Update Schedule
Service Mapping Shared
2 Model
resources
Payload in
Scheduler
Request … Simulator
+
Execution Obtain Execution Time
Distribution from SEM and
Resource Utilization State
SEMA SEMB SEMC
1
1. Extract protocol models from existing devices
2. Map onto protocols in existing network simulators
3. Synchronize execution with threads in a scheduler
simulator
Traffic Generation and
Tracing 14

14. Initial Results
Model Accuracy (10 pps, ICMP Echo)
2
Intra-Node Delay (ms)
1.5
1
Real World
Node Model
Vanilla Ns-3
0.5
0
0 200 400 600 800 1000 1200 1400
15
Packet Size (Bytes)

15. Cross-layer Adaptation
• Lindeberg, M., Kristiansen, S., Goebel, V., Plagemann, T.: “MAC Layer
Support for Delay Tolerant Video Transport in Disruptive MANETs”,
IFIP Networking 2011, Valencia, Spain, May 2011
<OverlayMessage>
500 m
Dts-Overlay Dts-Overlay
Sr - Source node
Ix - Intermediate node(s)
Sr I1 Crx- Carrier node(s)
Route
CCC - Command Control Center
Rejected UDP availability UDP
I2
packets +
CCC
Cr1 Cr2
+ MAC address
I3
500 m
Retransmission IP / OLSR /ARP status IP / OLSR
queue status
I4
I5
MAC MAC
Command and control center (IEEE 802.11 a/b) (IEEE 802.11 a/b)
Location of the accident
PHY PHY
(IEEE 802.11 a/b) (IEEE 802.11 a/b)
Distance=1750 m Node 1 Node 2
• MAC Support w/Cross-layer Interaction
• Check ARP if IP address is known (ARP Adapt)
• Check MAC transmission queue: if filling, link is down, stop using it
(Link Adapt)
• Return packets from MAC layer instead of dropping (MAC Return)
16
• We can reduce retransmission limit, and avoid most packet
losses!

16. Cross-layer Adaptation (cont.)
No “hard-wiring” to particular
protocol implementations
Standardized, convenient, and
efficient access to information
Using complex events
17

17. Multihoming in Heterogenous
Network Paradigms
• D. Rodriguez-Fernandez, I. Martinez-Yelmo, E. Munthe-Kaas, T. Plagemann:
“Always Best (Dis-)Connected: Challenges to Interconnect Highly
Heterogeneous Networks”, Special Issue of the Journal of Internet Engineering
on Future Network Architectures, 2012
Community
MANET DTN MANET Internet
Internet
Real World
3G
MANET
DTN
18
MANET

18. Multihoming in Heterogenous
Network Paradigms (cont.)
Applications Application
Cross-layering Information Framework
Community Socket API
Community Framework
Community Socket
Community Overlays
Monitoring Framework
Community A Community B …
Community Support Layer (CSL)
NSAL API
NSAL Internet MANET DTN
…
Underlays NSAL NSAL NSAL
IP IP (MANET) DTN …
Networking
Substrata
19
3G 802.11 …

19. Non-intrusive Clustering of MANETS
• Drugan, O., Munthe-Kaas, E., Plagemann, T.: “Detecting Communities
in Sparse MANETs”, IEEE/ACM Transactions on Networking, 2011
Topology from OLSR
routing table….. …. and with exact position… … and 100m range
20

20. Where are we now?
• All PhD students scheduled to submit their
thesis in 2012
• A good set of papers is published but several
are in the queue
• Most results are useful far beyond DT-
Stream (cf. highlights)
• Many of the core pieces are implemented for
an integrated demo prototype (also with
numerous MSc Theses)
21

21. Where do we go …
• Look for funding to move basic research
results of DT-Stream to applied research
results, i.e., integrated demo prototype ++
• Head for further long term challenges
… next slides
22

22. Future Technological Developments
• Bigger, faster, higher resolution, more media,
more Ds
– Data centers, scientific computing, home entertainment
• Smaller, everywhere, new range of I/O devices,
energy concerns
– Smart phones, sensors, actuators
• Ever increasing heterogeneity in computing and
networking
• è diversity, separation, and seamless integration
23

23. Rethink Fundamentals
• “there is a need to deeply rethink the
modelling and architecting of future pervasive
systems”
M. Conti et al., CNR
• “to fully realize the potential of CPS, the core
abstractions of computing need to be
rethought”
A. Lee, Stanford University
24

24. Rethink Fundamentals of the Future
Internet
Assume the hotel gets old….
… where will stakeholders invest
…upper floors renovations brings
“immediate” turn on investment
…but what if the foundations are rotten?
…have we invested enough in the
fundamentals of the Internet, IP, DNS, BGP?
Hotel Internet 25

25. Technological Challenges
• From cross-layer optimization to new foundations for
engineering computer/network systems?
– Layers simplify design and
engineering
– Layers simplify testing
– Layers are in conflict with
context aware solutions
26

26. Technological Challenges
• Smart phones and wireless sensors and
actuators:
– Promise to solve many challenges society faces,
e.g., sustainable environment etc., demographic
change ++
– Sharing enables many new solutions, e.g.,
pervasive sensing vs. privacy and ownership
– From application specific solutions to foundations
that span several/all application domains?
27

27. Non-technical (non-trivial) Challenge
• Acquire funding
28

28. Questions?
29