1. Using Collaborative Agents to Enrich Service Environments
Olga Ratsimor
Balaji Kodeswaran

2. Problem Statement
Wide disparity between the capabilities of wired and wireless networks
The wireless devices face frequent and possibly prolonged disconnections and bandwidth is limited
Variation in capabilities of mobile devices
Laptop vs. iPAQ vs. Palm vs. Cell phones
Wireless devices are resource limited in terms of processing power, battery etc.
Proliferation of wireless services and increased sophistication pushes the limits of wireless devices
Traditional text based news services have been enhanced to offer graphical and audio-visual multimedia content.

3. Problem Statement (cont.)
In ad hoc wireless networks, devices communicate with each other (within constrained boundaries) to use/provide services. There is no external coordination to improve overall service availability
Infrastructure wireless networks enforce a client server model between the mobile user and the base stations. This model is too restrictive and requires base stations to be strategically placed so that services can be offered to mobile clients

4. Proposed Solution
MH capabilities used to intelligently compose services that are best suited for that MH
Content/Data used by the services must be intelligently packaged and strategically distributed to maximize efficiency of the overall system
Use profiles/heuristics to proactively inject/distribute services into an ad hoc environment so as to improve the statistical probability of service availability
Service here is a web browser and content here is the web pages…..

5. List of Components Service Portals Mobile Devices Services
Base stations that host services and are connected to a wireline network
Mobile Devices
Agent Platform
Services
Service Specification
Service Agents
Service Data Volumes

6. Network Model The network is comprised of two distinct types of zones
Landing Zones
Mobile Devices in this zone can communicate with a Service Portals (infrastructure)
Transit Zones
MH in this zone can communicate with peers only (ad hoc)
Combination of infrastructure and ad hoc wireless network concepts
A Mobile Device can talk to other devices in its environment
A Mobile Device can also talk to fixed wireline components like mobile support stations or base stations

7. Service Portal
Service Portals act as base stations and are located through out the network
Each Portal is aware if all of its immediate neighbors
Portals perform following duties
Actively advertise presence and host different types of services
Perform dynamic data/content management for the different services so that MHs are offered only data that they can handle/use
Dynamically create “Service Data Volumes” that are distributed to MHs so that an MH is not required to download all data needed for a Service at once
Caching: communicate with neighboring portals to inform them of possible future service demands in their vicinity
Monitor the usage patterns of services on a MH passing through a Landing Zone to extrapolate what services/content may be required in neighboring Transit Zones and schedules to have these services/content delivered through other MHs that are heading towards these zones

8. Service Specification
Description of the Service
Expressed using descriptive languages
Expresses high level requirements for a service
News paper reader requires a UI display
Audio player requires speakers
Audio recorder requires a microphone etc.

9. Service Agent
Each Service specification is associated with multiple implementations called Service Agents that implement that specification
Service Agents can be migrated to a MH on demand
Service Agents can also be automatically dropped from a MH when no longer needed
Service Agents are provided with “Service Data Volumes” on which they operate

10. Service Data Volume
Service data is pre-divided into Data Units. Data Unit is the smallest unit of data
Articles or Individual pages of a News paper
Each Song of musical score
Each Data Unit could be of varying size. “Size” here depends on the service specification
Words on a Page for a news reader
Minutes for a song
Multiple Data Units are aggregated into “Service Data Volumes” for distribution to MHs

11. Mobile Host
Wireless devices with varying capabilities running a thin Agent Platform
Determine if the vicinity is a Landing Zone or a Transit Zone
Communicate with peers and with Service Portals
Provide APIs that allow for device capability discovery
Support of dynamic loading and unloading of Service Agents and Service Data Volumes
Profile Service Agents
Currently registered Service Agents, running times, etc
User actions are logged by respective Service Agents
Which pages of a newspaper has the user read

12. Surveyor
At start up the Surveyor Agent jumps into the device and evaluates device capabilities
Surveyor composes a Capability Report which is sent to the Service Portal
Depending on this Capability Report the Service Portal sends a list of appropriate services to the device
User selects desired service(s)

13. What can your Device handle?
The Surveyor
What can your Device handle?
User selects
services
Give some services?
List of
potential
services
Capability
Report
Service
Portal #1

14. NUMI Flavors Service Distribution Modes MH mobility characteristics
On Demand
Relies on logs on mobile hosts
Proactive
States are maintained at Service Portals that track expected user mobility. Service Portals use this to pre-equip environments.
MH mobility characteristics
Direction aware
Caching is optimized
Direction unknown
Conservative caching is used (all neighboring portals cache)

15. On Demand Service Distribution
The device receives the appropriate Service Agent(s)
The device receives the Service Data Volume, enough to last until the next Service Portal (the longest hop)
If the direction of the device movement is not known the Portal notifies all its neighboring Portals about services that have been recently requested
The neighboring Portals preload the expected Service Data Units
The compilation of Volumes does not happen till the MH arrives at that Landing Zone
When the Mobile Host arrives it receives the next Service Data Volume

16. Proactive Service Distribution
In addition to on demand service distribution
Neighboring Portals are notified of expected time of arrival
This state is used to proactively distribute services if the MH does not arrive on time
If the direction of the MH movement is known then only the next hop Portal is notified. Otherwise all its neighboring Portals are notified

17. Notification of service usage
Portal #3
Service Distribution
Notification of service usage
page1
page1
Service
Portal #1
Service
Portal #2
5 min
15 min
3 min
Service
Portal #4

18. On Time Mobile Host Arrival
Service
Portal #2
On Time Mobile Host Arrival
MH1 2 1
MH1 4 2
2&3
2,3&4
Notification of service usage
Time t=15
MH1 1
Time t =10
15 min
MH1 1
Service
Portal #1
Time t =0

19. Rest Stop Scenario The Mobile Device could stop along the way.
When MH is about to run out of service data it starts looking for the next Service Data Volume.
Service Data is available in the neighborhood
Neighborhood provides the requested data
Service Data is unavailable
passing Mobile Hosts log requests
Portals monitor the logs of incoming MHs
Portals identifies missing services and and arranges to deliver the services to the neighborhood
In addition a Portal can inform its neighboring Portals about missing the Services and Data.

20. Request for Service Continuation
15 min
To Service
Portal #4
Portal #3
Service
Portal #1
Portal #2
Portal #5
Portal #6
21-40
Request for Service Continuation
MH2
MH6
MH3
21-40
MH1
1-20
Time t=5
MH3
Time t=15
MH2
21-40
MH1
1-20
The High Volume Traffic
with Rest Stop (On Demand)

21. The low traffic with rest stop and inter portal communication
15 min
To Service
Portal #4
Portal #3
Service
Portal #1
Portal #2
Portal #5
Portal #6
21-40
Notify neighbors about service demand
Request for Service Continuation
MH3
MH1
1-20
Time t=5
MH3
Time t=15
MH3
MH1
1-20
MH3
MH5
MH4
21-40
The low traffic with rest stop
and inter portal communication
(On Demand)

22. Proactive Service Transfer
The Mobile Host might not be resource rich. It could be unable to store enough information till the next Portal
If the direction is known the current Portal can tell the next hop Portal that the next hop Portal should send the the next chunk of data with some other Mobile Host that is heading towards the Mobile Host in need.

23. Notify the next hop to initiate proactive service transfer
15 min
To Service
Portal #4
Portal #3
Service
Portal #1
Portal #2
Portal #5
Portal #6
Time t=10
MH1
1-10
Notify the next hop to initiate proactive service transfer
MH3
10-15
MH2
10-15
Time t=5
MH1
1-10
MH1
1-10
Proactive Service Transfer

24. Group Travel
Mobile Device requires service, however does not have enough capacity to store the minimal Service Data Volume
If there is a group of Mobile Hosts that are traveling along the same route the Service Data can be shared among the devices
If route is not known the following heuristic can be used
The statistical probability of Service Data Volume use should be proportional to the number of hosts it is distributed to

25. Multi-Hop Known Route
Extension of our Proactive Service Distribution scheme
Look beyond next hop neighboring Portals
Complete route of device used to inform all Portals on route about the service needs of this device and the expected times of these needs
Portals repeatedly update other Portals on the route when they detect changes in mobility characteristics of the device and service usage patterns

26. Notify the portals along the route
Route update/
confirmation
Service
Portal #3
Portal #1
Portal #2
MH1
10-15
Notify the portals along the route
MH1
5-10
5-10
MH2
20 min
15-20
MH3
15-20
MH3
20-25
MH3
MH1
1-5
5-10
MH2
10 min
MH1
1-5
Proactive Service Transfer
With multi Hop Route
Time t=5
Time t=10

27. Notify the portals along the route
Route update/
confirmation
Service
Portal #3
Portal #1
Portal #2
MH1
10-15
MH1
15-10
MH1
20-25
Notify the portals along the route
20 min
15-20
MH3
15-20
MH3
20-25
MH4
MH4
20-25
20-25
MH4
10 min
Proactive Service Transfer
With multi Hop Route
Time t=5
Time t=10
Time t=15
Time t=20

28. Thank You!
Q.E.D.