UMass DieselNet:A Disruption-Tolerant Network Testbed

UMass DieselNet:A Disruption-Tolerant Network Testbed

John BurgessDepartment of Computer Science

UMass Amherst

John BurgessDepartment of Computer Science

UMass Amherst

DieselNetDieselNet

Vehicular DTN deployed in Amherst and surrounding county

Now includes 40 buses

Each bus: Linux “brick” computer; USB 802.11b adapter; 802.11b AP; GPS receiver, 40GB hard drive

Buses transfer data as they pass by each other and via available hot spots.

The OpenbrickThe Openbrick

• Small form factor

• Plentiful I/O

• Binary availability for x86

• 60w peak power draw

• Low heat dissipation

DieselNet Software ConsiderationsDieselNet Software Considerations

Autonomous operation and “shutdown” Maximal failure tolerance

No remote administrator login or local terminal Physical inaccessibility during operation (6am - 1am) Nodes versus support staff

Handle network interface configurations Support IP programs

Handle bundle routing Support DTN programs

Autonomous operation and “shutdown” Maximal failure tolerance

No remote administrator login or local terminal Physical inaccessibility during operation (6am - 1am) Nodes versus support staff

Handle network interface configurations Support IP programs

Handle bundle routing Support DTN programs

Init and RestoreInit and Restore

Linux and initial software stored on 1st partition All DTN software, logs, bundles, cached web

content, etc. stored on 2nd partition Restore checks for the presence of critical files If any critical files are inaccessible

Clear extended partition Restore initial software package from system disk

Otherwise, Init starts system software

Linux and initial software stored on 1st partition All DTN software, logs, bundles, cached web

content, etc. stored on 2nd partition Restore checks for the presence of critical files If any critical files are inaccessible

Clear extended partition Restore initial software package from system disk

Otherwise, Init starts system software

1GB hdc1 39GB hdc5

AutoupdateAutoupdate

Install new software Check for new gzip files on prisms web site Verify prisms signature Install update atomically

Sync system clock with server Report current location Report log entries

Connection events Program error messages

Upload files Bzip file, MIME encode it, and upload via HTTP request header

Install new software Check for new gzip files on prisms web site Verify prisms signature Install update atomically

Sync system clock with server Report current location Report log entries

Connection events Program error messages

Upload files Bzip file, MIME encode it, and upload via HTTP request header

LiveIPLiveIP

Manage network interfaces 802.11b

Scan for ssid broadcasts on all channels Connect to other buses

Hash foreign bus MAC address to determine subnet

Connect to access points DHCP

Ping foreign device to decide when to resume scanning Reload 802.11 driver to clear malfunctions

Additional interfaces to be managed 900mhz long-range radio (1km) CDMA modem

Manage network interfaces 802.11b

Scan for ssid broadcasts on all channels Connect to other buses

Hash foreign bus MAC address to determine subnet

Connect to access points DHCP

Ping foreign device to decide when to resume scanning Reload 802.11 driver to clear malfunctions

Additional interfaces to be managed 900mhz long-range radio (1km) CDMA modem

GPSupdateGPSupdate

Receive NMEA formatted information via RS232 Compute speed, direction, etc. Periodically log location Provide location information to onboard programs

Receive NMEA formatted information via RS232 Compute speed, direction, etc. Periodically log location Provide location information to onboard programs

DTNdaemonDTNdaemon

Accept data and send bundles via local TCP socket

Route bundles according to configured protocol MaxProp

Deliver data to appropriate onboard programs Programs connect via TCP socket Programs register as appropriate destination application

Platform and IP network interface independent Java implementation with no external dependencies DTN2 2004 bundle format compatibility

Accept data and send bundles via local TCP socket

Route bundles according to configured protocol MaxProp

Deliver data to appropriate onboard programs Programs connect via TCP socket Programs register as appropriate destination application

Platform and IP network interface independent Java implementation with no external dependencies DTN2 2004 bundle format compatibility

Software ComponentsSoftware Components

Init and Restore Perl and Python

Auto update Python

Live IP Java 1.4

GPS update Python

DTN daemon Java 1.4 and linux-only Java 1.3

Init and Restore Perl and Python

Auto update Python

Live IP Java 1.4

GPS update Python

DTN daemon Java 1.4 and linux-only Java 1.3

Connection EventsConnection Events

Red dots indicate bus-to-bus transfers

(1 month) Measurement of real TCP throughput Traces collected everyday

Red dots indicate bus-to-bus transfers

(1 month) Measurement of real TCP throughput Traces collected everyday

MeasurementsMeasurements

Buses log their status via available access points (and update software).

Transfer duration

Inter-transfer opportunity timeBytes transferred

Future WorkFuture Work

Deploy different DTN routing protocols Develop useful disruption tolerant applications Expand network to include other types of nodes

Deploy different DTN routing protocols Develop useful disruption tolerant applications Expand network to include other types of nodes

SummarySummary

DieselNet is a DTN Testbed deployed on public transportation busses

Network inaccessibility often corresponds to physical inaccessibility, making DTN administration difficult

DTN system administration must be accomplished in a disruption-tolerant manner

Current above-IP DTN solutions must handle configuration of IP, Link, and physical network

Future solutions running above the link layer will still need to configure the link and physical layer

DieselNet is a DTN Testbed deployed on public transportation busses

Network inaccessibility often corresponds to physical inaccessibility, making DTN administration difficult

DTN system administration must be accomplished in a disruption-tolerant manner

Current above-IP DTN solutions must handle configuration of IP, Link, and physical network

Future solutions running above the link layer will still need to configure the link and physical layer