Disruption Tolerant Networking for CONDOR - ietf.org · Robert Durst Salil Parikh Keith Scott Jason...
Transcript of 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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MITRE © 2006 The MITRE Corporation. All rights reserved.Approved for Public Release; Distribution Unlimited. 06-0319
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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MITRE © 2006 The MITRE Corporation. All rights reserved.Approved for Public Release; Distribution Unlimited. 06-0319
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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MITRE © 2006 The MITRE Corporation. All rights reserved.Approved for Public Release; Distribution Unlimited. 06-0319
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
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500
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10 30 50 70 90 110
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File Retrieval Time (seconds)
Num
ber o
f File
Tra
nsfe
rs
HTTPDTN
10 KByte File Transfers in 24 hours
368
3580
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500
1000
1500
2000
2500
3000
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Completed
HTTP
DTN
Abandoned 10-KByte File Transfers in 24 hours
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115
0
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60
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120
140
Abandoned
HTTP
DTN
..
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MITRE © 2006 The MITRE Corporation. All rights reserved.Approved for Public Release; Distribution Unlimited. 06-0319
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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MITRE © 2006 The MITRE Corporation. All rights reserved.Approved for Public Release; Distribution Unlimited. 06-0319
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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MITRE © 2006 The MITRE Corporation. All rights reserved.Approved for Public Release; Distribution Unlimited. 06-0319
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
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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?