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Transcript of Delay tollerent network
7/27/2019 Delay tollerent network
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A Delay-Tolerant NetworkArchitecture for Challenged
Internets
Mayur MuleyTE IT 11238
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Outline
Introduction
Challenged Internet
Characteristics of Challenged internets & Current solutions
Can we use TCP/IP for architecture?
A Delay Tolerant Message Based Overlay Architecture
Application Interface
Conclusion
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Introduction
Three key assumption to achieve today’s end-to-end inter-process communication:
1.An end-to-end path exists between a data source and itspeer(s).
2.The maximum round-trip time between any node pairs in
the network is not excessive.
3.The end-to-end packet drop probability is small.
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Challenged Networks
What is challenged network?
Communication environment where expectation of link or path
characteristics no longer hold
Challenged networks :
1.Exotic Media Networks.
2.Military Ad-Hoc Networks..
3.Sensor/Actuator Networks.
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Challenged networks ( cont. )
A general purpose message-oriented reliable overlayarchitecture as the appropriate approach to tie togethersuch networks, forming an “ internetwork of challenged
internets.” Its design is influenced by :
the internet design( interoperability)
The non-interactive delivery semantics of electronic mail
US Postal System.
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Current solutions
Some approaches to adapt Internet to unusual
environments:
1.Link-repair approaches.
2.Use proxy agents.
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Characteristics of Challenged Networks
Path and Link Characteristic
1.High Latency, Low Data Rate.
2.Disconnection: Non-faulty disconnections
A. Motion
B. Low-duty-cycle
3.Long Queuing Times
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Characteristics of Challenged Networks
Network Architectures
1.Interoperability Considerations.
Networks may use application-specific framing formats,data packet size restrictions, limited node addressing andnaming etc.
2.Security:
typically require some exchange of challenges or keys.
Uses base idea of public key encryption technique.
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Can we use TCP/IP?
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Ans : No
WHY ? Reasons are:
◦ Transport layer (TCP)
High latency and moderate to high loss rates severely limit TCP’sperformance
◦ Network layer (IP)
Performance affected by loss of fragments
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Can we use TCP/IP?
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A DELAY TOLERANT MESSAGEBASED OVERLAY ARCHITECTURE
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Abstraction
Message switching
◦ Use message aggregates or “bundles”
Allows network’s path selection and scheduling functions a-
priori knowledge of the size and performance requirementsof data transfers
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Regions and DTN Gateways
DTN gateways are interconnection points betweendissimilar network protocol and addressing families called
regions◦ e.g. Internet-like, Ad-hoc, Mobile etc.
Function of DTN gateways :
◦ Perform reliable message routing
◦ Perform security checks
◦ Store messages for reliable delivery
◦ Naming & addressing
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October 14, 2013 Anshul Kantawala 14
Name Tuples
Two variable length portions
◦ Region name Globally-unique.
Used by DTN gateways for forwarding messages
◦ Entity name Resolvable within the specified region, need not beunique outside it
◦ E.g. { internet.icann.int, http://www.ietf.org/ }
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Class of Service
Similar to the Postal service
◦ Delivery priority: low, ordinary, high
◦ Notifications of mailing, delivery to receiver and routetaken
◦ Reliable delivery using custody transfer at each routinghop
Regions and DTN Gateways
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Security
Each message contains◦ Identity of sender
◦ Requested class of service (CoS)
Use public key cryptography
First DTN router verifies user and validates CoSrequest.◦ Re-signs message using its key and sends it back
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APPLICATION INTERFACE
The DTN architecture is built as an overlay
network using messages as the primary unit of data interchange.
Application interface is non-blocking
◦ Also has registration and callback functionsbetween bundle-based applications and the localforwarding agent
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Conclusion
DTN architecture attempts to provide interoperablecommunications between and among challenged networks.
Design uses message switching with in-networkretransmission, late-binding of names and routing tolerantof network partitioning.
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THANK YOU!!
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ANY QUESTIONS ?
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