Gonzalez, Pete

Rich, Tom

NASA Technical Reports Server

NASA JSC CD231 – Mission Systems Strategic Projects
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
Delay / Disruption Tolerant 
Networking Enhancements for 
Streaming Data
Tom Rich / Pete Gonzalez
May 8, 2017
https://ntrs.nasa.gov/search.jsp?R=20170008898 2019-08-29T23:16:10+00:00Z
2DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
Agenda
• Delay / Disruption Tolerant Networking (DTN)
• Opportunities for DTN Enhancement
• DTN BSS Payload Conditioning
• bss_player Stream Control Application
• Demo Setup, Re-use Elements
• JSC / JPL  DTN / DSN Overview
• DTN BSS Telemetry Demo
• BSS Player Video Architecture
• DTN BSS Video Demo
• Summary
3DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
Delay / Disruption Tolerant Networking (DTN)
• DTN provides store-and-forward data transmission.
– Missing data is automatically detected and re-transmitted.
– Data is held at the origination node until receipt confirmation is 
received from the destination node.
• DTN is delay tolerant.
– DTN is designed for transmission delays at interplanetary 
distances
• Up to 20 minutes transmission delay for a Mars mission
• NASA’s Spacecraft Communications and Navigation (SCaN) 
Program Office has directed that DTN be incorporated into the Deep 
Space Network.
• Therefore, the MCC will need to account for the effects of DTN on 
data received from the DSN.
• This work addresses operational enhancements to the Interplanetary 
Overlay Network (ION). 
4DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
Opportunities for DTN Enhancement
• Situation:  An unconditioned DTN data stream produces out-of-order data, as missing data 
frames are re-transmitted and mixed in with the real-time data stream.
– Out-of-order data would look like a transient glitch on a flight controller display.
– A data gap would be preferable to out-of-order data.
– This problem is addressed by the Bundle Streaming Service (BSS) bundled with ION.
– However, the data samples are delivered in bursts due to DTN (LTP) aggregation.
• This presents a problem for applications that rely on a steady stream of samples, 
such as voice and video.
• A way to meter the data is needed.
• Situation: The user needs to know when 100% of the data has been received.  Delay Tolerant 
Payload Conditioning (DTPC) does do this.  This work uses a different approach.
• Situation:  For timing sensitive applications, such as H.264 compressed video, the 100% 
complete received data stream timing should match the original timing, even though the 
original data samples may have been aggregated into larger blocks for space-to-ground 
transmission.
• All three of these streams are required simultaneously over the Licklider Transmission Protocol 
(LTP), which is DTN’s long haul space-to-ground (aggregating) protocol.
• All of these situations are addressed by DTN BSS Payload Conditioning.
5DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
DTN BSS Payload Conditioning
• DTN BSS Payload Conditioning provides:
– A metered real-time data stream
• Monotonically increasing time tags and sequence numbers, no out-of-order 
packets, may have gaps
• Metering;  timing of the output data stream matches the original, even though 
aggregation may have occured during space-to-ground transmission.
– Real-time metering will be important for transmission of voice over DTN. 
– A fully conditioned data stream
• 100% confirmed reception;  real-time data advancement when 100% is reached
– A metered, fully conditioned data stream
• Suitable for H.264 compressed video;  lags behind real-time
• These capabilities require:
– (Minimal) modification to the DTN bpsend() function to add a unique sequence number 
and a microsecond time tag to the DTN ECOS extension block
– Modification to the ION DTN Bundle Streaming Service (BSS) library to add these two 
new parameters to the BSS database
– The bss_player data stream control application
• All three types of streams are available simultaneously
• bss_player can distribute each stream independently over BP, UDP, or multicast
6DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
bss_player Stream Control Application
7DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
Demo Setup, Re-use Elements
• A DTN node in the iPAS lab, JSC Bldg. 29 simulates the vehicle 
transmission point.
• The simulated Deep Space Operations Center (DSOC) at JPL anchors 
the DTN LTP space-to-ground link.
• JPL models the space link with a 2 sec. one-way-light-time (OWLT) 
delay, and a 2% frame drop rate on the downlink.
• JPL provides the multi-center DTN distribution node.
• The OTF in JSC Bldg. 30 provides five independent DTN data reception 
nodes.
– Their sole connectivity is through JPL
– This configuration simulates geographically dispersed control 
centers
8DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
JSC / JPL  DTN / DSN Overview
DTN / LTP
Telemetry, Voice, 
Video Downlink
DTN / LTP
Command, Voice
Uplink
Initial Cislunar Habitat
Software Defined Radio
iPAS Lab, JSC Bldg. 29
Protocol Test Lab@JPL
DSN Operations Center Sim
Space-to-Ground Comm Link Sim
2 sec. one way light time delay
2% frame drop rate on the downlink
0.1% frame drop rate on the uplink
Available 24 / 7 / 365
OTF@JSC Bldg. 30PTL@JPL
UDP, STCP, DGR 
DTN Convergence Layers
9DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
DTN BSS Telemetry Demo
• bss_player, showing metered realtime, 100% 
conditioned, and metered replay data streams
• Sample telemetry display of metered realtime 
stream (red)
– Skipped sequence numbers are evident, 
indicating missing data.
– Sequence numbers monotonically increase
NASA JSC CD231 – Mission Systems Strategic Projects
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
DTN Node 6 (OTF)
ION + 
BSS Player 
DTN Node 2
BSS 
Database VLC
(Playback)
Playback
Data
BP-enabled 
Data Capture 
App
Video
BP Bundles
over LTP
Axis
Camera
In iPAS
BSS Player Video Architecture
VLC
(Realtime)
Realtime
Data
iPAS (Vehicle)
EARTH DTN Node 7 (JPL)
LTP & STCP 
Daemons 
BP Bundles
over STCP
SPACE
VLC
(Conditioned)
Conditioned
Data
11DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
DTN BSS Video Demo
• bss_player, showing metered realtime, 100% conditioned, and replay data streams
• Video display of original low-def 4 fps Motion JPEG video signal, provided by an 
Axis 214 PTZ camera in the iPAS Pathfinder lab in Bldg. 29
• Video display of metered BSS realtime signal (red), propagated through the JSC / 
JPL  DTN / DSN simulated space-to-ground and ground-to-ground network
– Video glitches correspond to dropped MJPG frames.
– Real-time received video lags the original by ~2 sec., the modeled OWLT
• Video display of real-time 100% conditioned DTN video signal (green)
– Video freezes while bss_player waits for retransmission of missing data.
– When all missing data are restored, the video jumps to the most current 
frame.
– Intervening video is skipped;  events will be missed.
• Video display of metered replay 100% conditioned DTN video signal (blue)
– Smoothly displays the complete video signal
– Lags behind real-time
12DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
Summary
• DTN Bundle Streaming Service (BSS) addresses the problem 
of out-of-order data in real-time displays.
– DTN BSS Payload Conditioning includes this capability. 
Plus, it adds metering capability to the real-time stream, 
so that the output timing matches the input timing.
• DTN BSS Payload Conditioning addresses the need to 
confirm reception of 100% of the data transmitted over DTN, 
and to know real-time when 100% reception has occurred.
• DTN BSS Payload Conditioning addresses the need to match 
the output data timing to the input timing for the fully 
conditioned data stream.
– Important for timing sensitive data streams such as H.264 
compressed video
13DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
Questions?
14DTN Operational Enhancements for Streaming Data May 8, 2017
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
Backup
NASA JSC CD231 – Mission Systems Strategic Projects
Approved for Public Release via the NASA Science and Technical Information Process DAA 39211
DTN Node 3
BSS 
Player 
DTN Node 1
Controller 
Headset
Astronaut
Voice
BP-enabled 
Data Capture 
App
BP Bundles
over LTP
Astronaut 
Headset
DTN Voice Communication Architecture
ISS
EARTH DTN Node 2
LTP & BSSP 
Daemons 
BP Bundles
over BSSP
SPACE
BSS 
Player 
BP-enabled 
Data Capture 
App
Flight 
Controller
Voice
Astronaut
Voice
Flight 
Controller
Voice
DTN 
Phone 
App
DTN 
Phone 
App


Delay/Disruption Tolerant Networking Enhancements for Streaming Data

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server