Disruption Tolerant Networking for CONDOR - ietf.org · Robert Durst Salil Parikh Keith Scott Jason...

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MITRE © 2006 The MITRE Corporation. All rights reserved.Approved for Public Release; Distribution Unlimited. 06-0319

Robert DurstSalil ParikhKeith Scott

Jason AndresenKarl TritchlerTom Ullrich

Tim Bultman

Disruption Tolerant Networking for CONDOR

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Marine Corps Approach: CONDOR(C2 On-the-Move Network, Digital Over-the-Horizon Relay)

Unsolved problems:– Maneuver still disrupts

communication– Disruption effects

are persistent– Disruption causes

databases todesynchronize

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DTN for CONDOR:How can DTN help the USMC NOW?

0 DTN can help maintain reliable communication across periods of unreliable connectivity through in-network store and forward

0 DTN is useful for data transfers in which the time-value of the information exceeds the duration of the network disruption(s)- Likely wins: imagery, logistics information, email,

chat(?)- Unsure: real time position/location information- Unlikely: fire-control

0 DTN must support a relevant set of applications to enable forward C2- COP maintenance in disrupted environments- Web access- Chat- Email- Whiteboard?

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CONDORGateway

WebServer

CONDOR JumpCommand Vehicle

DTN in Emulated CONDOR Context

DTN DTNDTN DTNDelay 50ms64kbps

Lossy/Outage Periods

Delay 800ms64kbps

Lossy/Lossless Periods

“FCS” “FCS”

Inmarsat

HTTP end-to-end

DTN hop-by-hopstore-and-forward

InmarsatFCS FCSDelay 50ms

64kbpsLossy/Outage Periods

See also: M. Demmer, K. Fall, “Implementing Delay Tolerant Networking” for similar experiments

TCP

TCP TCP TCP

CONDORGateway

Web Browser

CONDOR JumpCommand Vehicle

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Distribution of File Retrieval Times

On lossless links: 7.15 seconds per transfer using TCP, ~10 seconds using DTN

Consecutive 10-KByte File Retrievals over 24 hours, using HTTP and DTN

0

500

1000

1500

2000

2500

3000

3500

4000

10 30 50 70 90 110

130

150

170

190

210

230

250

270

290

File Retrieval Time (seconds)

Num

ber o

f File

Tra

nsfe

rs

HTTPDTN

10 KByte File Transfers in 24 hours

368

3580

0

500

1000

1500

2000

2500

3000

3500

4000

Completed

HTTP

DTN

Abandoned 10-KByte File Transfers in 24 hours

0

115

0

20

40

60

80

100

120

140

Abandoned

HTTP

DTN

..

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user

INMARSATterminal

EPLRSCisco 3725

Cisco 2811

KG-250

DTN CONDOR Integration

Goals- Incorporate DTN functions into

CONDOR in a deployable form- Minimize imposition on size,

weight, powerCurrent packaging approaches- Cisco Intrusion Detection System

module (FY05) - Stand-alone PC/104 unit (FY06)- Cisco Mobile Router add-in (FY06)

Applications in work- C2PC support- Web Services- Web Proxy- Chat Proxy- SSL SupportCONDOR Gateway cable map

DTN

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DTN CONDOR Alternative Packaging

0CIDS/Application Oriented Networking Module- Standard Cisco module- AON architecture- Powered through host Cisco router

0Stand-alone PC-104 unit- All solid-state, extended temp range,

NIMA-sealed unit (6” x 5” x 5”)- Router-independent- Vehicular power (9-60vDC)

0 Integrated DTN and Cisco Mobile (“Grizzly”) Router- Same PC-104 stack as above- Integrated with Cisco PC-104 extended

temperature router- CONDOR Red-side router replacement

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DTN-Web Proxy Operation

0 DTN’s web proxy provides transparent access to DTN services0 Adds user-directed search to further reduce interactivity

Request Page

Get PagesSend request bundle

CONDORGateway

Populate cachewith bundle

Disrupted & Delayed Network Connected

Network

●

●

●

●

●●

●

Aggregated and compressed pagesin bundle

CONDOR JumpCommand Vehicle DTN-Web

Proxy

Deliver Pages

Confirm Request

Standard HTTP

DTN-WebProxy

Tim

e

●

●

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DTN Support for Chat0 Transparently deal with “net splits” and “net joins” by automatically

rejoining when connectivity is re-established. 0 Keep temporarily untransmittable messages queued for a specified

amount of time and then allow them to pass normally if the network reconnects before the message expire.- Optionally add tags (timestamps) to old messages to avoid

confusing other users in the network.0 Use a proxy server between IRC servers to allow users to use their

existing clients and servers.- Use local IRC server at CONDOR to insure timely uninterrupted

local chat using conventional communications protocols- Use DTN Chat-server proxy between local and remote servers

0 Current status:- Designed, implemented DTN Chat-server Proxy that interacts with

a (any) local chat server and appears to be another server- Provides server to server proxying via DTN- Working, but not yet stable enough for deployment

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Experimental Design (Work in Progress):DTN Proxy for C2PC Using Cursor on Target (CoT)

0 No direct Gateway-to-Gateway traffic across Over-the-Horizon link.- CONDOR red-side router configured to block C2PC traffic- DTN’s CoT proxy maintains sync between Gateways indirectly via CoT

0 Open questions:- How to transition from Gateway-to-Gateway to DTN-CoT Proxy when Over-

the-Horizon link is invoked?- How best to synchronize a Gateway by way of a C2PC Client (via CoT)?- How to ensure all events of interest are accessible? How to limit sync only

to events of interest (e.g., PLI, tracks, overlays, possibly location-specific)?

Over-the-Horizon Link

CONDOROn-the-Move LAN Tactical Operations Center

CONDOR

DTN Router

& CoTProxy

Clie

nt

Clie

nt

Clie

nt

DTNRouter

&CoTProxy

Clie

nt

Clie

nt

Clie

nt

Gat

eway

Gat

eway

Clie

nt

Clie

nt

XML over TCP (CoT) DTN CoT Proxy (to be built) Existing C2PC CoT plugin (possibly to be enhanced)

Part of CONDORpayload

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Web-Service Apps in DTN Setting0 Typical browser-based SOAP apps are unsuited to

delayed or disruption-prone environments- Subject to HTTP synchronous request-response

limitations 0 App logic needs modification

- To use polling, events, messages- To be cache-friendly, use configurable timers

0 App-specific DTN proxy - Serves as DTN gateway - Performs caching function

0 Issues- Transparent solution unlikely, only general

guidelines for design- Client configuration complications

0 Apps under examination- MarineLink- Lightweight Collaborative Whiteboard

Browser

WebServer

HTTPProxy

HTTPClient

DTN AppProxy

DTN AppProxy

HTTP socket

HTTP socket

Bundles

Server

Client

Client-sideDTN Proxy

Server-sideDTN Proxy

ChallengedNetwork

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DTN Support for SSL0 Needed to support Outlook Web Access (currently used by

USMC for email)0 Initial design (not yet implemented/tested):

- SSL uses record-oriented protocol over TCP for all exchanges

- Proxy encapsulates SSL records in Bundles- Proxy presents an “HTTPS Proxy” interface (or can be

“interception” style)- Proxy handles reordering/reassembly of SSL records at

decapsulation point.0 Potentially a general approach to support HTTPS/SSL traffic

- Initial characterization of OWA delay sensitivity planned using delay emulator

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Next Steps…0 How can we best complete and transition this work to the

USMC? What should we be doing now to ensure smooth handover?

0 What steps can be taken to ensure that the transition to operational use is smooth and effective?- Exercise/evaluation by USMC Comm Officers?- Maintenance and support arrangements?

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Thanks!Questions?

Disruption Tolerant Networking for CONDOR - ietf.org · Robert Durst Salil Parikh Keith Scott Jason...

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