Transcript Delay Tolerant Networking and Content/Service

Workshop at Space Internetworking
Center (SPICE), Xanthi
Delay Tolerant Networking and
Content/Service-Centric Networking
Torsten Braun
Universität Bern
[email protected]
rvs.unibe.ch
Torsten Braun: Service-Centric Networking
Overview
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Computer Networks and Distributed Systems @ U Bern
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Content- and Service-Centric Networking in
Mobile and Delay-Tolerant Networks
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Conclusions and Outlook
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Torsten Braun: Service-Centric Networking
Research Projects @ Computer Networks
and Distributed Systems
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Opportunistic Routing for
Highly Mobile Ad-hoc Networks
Authentication, Authorization,
Accounting, and Auditing in Wireless
Mesh Networks (A4-Mesh)
Mobile/Wireless
Content-Centric Networks
Traffic Adaptivity in
Wireless Sensor Networks
Location Based Analyser
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Torsten Braun: Service-Centric Networking
A4 Mesh: Environmental Monitoring with
Wireless Mesh Networks
Thomas Staub, Benjamin
Nyffenegger, Desislava
Dimitrova, Torsten Braun:
Operational Support of
Wireless Mesh Networks
Deployed for Extending
Network Connectivity, 1st
International Workshop on
Opportunistic Sensing and
Processing in Mobile
Wireless Sensor and
Cellular networks
(MobiSense), Bilbao,
May 9-11, 2011
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Torsten Braun: Service-Centric Networking
EU FP7 Wisebed (until 6/2011):
WSN Testbed Management System
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Torsten Braun: Service-Centric Networking
TARWIS Experiment Configuration
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Torsten Braun: Service-Centric Networking
Recent WSN Experiments
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Maximally Traffic-Adaptive and Energy-Efficient MAC Protocol
[EWSN 2010] and
Software-based Energy Usage Estimation [EWSN 2011]
Adaptive Forward Error Correction
TCP Support
— Local data and acknowledgement retransmissions
— Adaptive retransmission timeouts based on activity monitoring and
path length detection
— Duplicate suppression
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Torsten Braun: Service-Centric Networking
Motivation for Content-Centric Networking
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Today’s network traffic is dominated by information retrieval
rather than point-to-point communication between machines
or humans.
Today: huge amount of data sent redundantly on a link
Circuit communication model is not considered as appropriate
any more.
Future communication architecture should focus on
information objects instead of nodes.
Today, wires and memories solve complimentary issues:
— Wires move information in space.
— Memories move information in time.
Future communications architecture should unify both issues.
[modification of slides on CCN from NDN and CCNx projects]
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Torsten Braun: Service-Centric Networking
Traditional Web Retrieval / Web Services
search engine /
service registry
user’s end system
web server /
web service
DNS server
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Torsten Braun: Service-Centric Networking
Related Work
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Peer-to-Peer Networks
— Construction of overlay networks
— Content / service discovery,
e.g., using distributed hash tables, flooding, random walks, etc.
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Web Caching
— Providing content for local users
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Content Distribution Networks
— Routing and redirection of HTTP requests
— Cache management
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Torsten Braun: Service-Centric Networking
Content-Centric Networking (CCN)
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[Jacobson et al., ACM CONEXT, December 2009]
Combination of content lookup and message routing
Idea: describe the users’ interests in the message header,
but not where to get it.
Messages (using XML encoding)
— Interest: content name, selector
— Data: content name, signature (info), data
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Hierarchical content names
— Example: /unibe.ch/braun/lecture/20100405
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Torsten Braun: Service-Centric Networking
Related Projects
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NDN = Named Data Networking, www.named-data.net
CCNx = Open Source Core Software Project for
Content-Centric Networking, www.ccnx.org
Scalable and Adaptive Internet Solutions (SAIL),
www.sail-project.eu
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Torsten Braun: Service-Centric Networking
IP Model
FIB
FIB: Forwarding Information Base
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Torsten Braun: Service-Centric Networking
Processing of Interest Message in CCN
Longest prefix match on content name in Content Store (CS):
returning data and discarding Interest
2. Pending Interest Table (PIT) match:
adding request to PIT and discarding Interest
3. Forwarding Information Base (FIB) match:
forwarding of Interest towards data
1.
— FIB population by announcements of content availability
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Torsten Braun: Service-Centric Networking
CCN Model: Match in Content Store
CS
Name
FIB
Data
PIT
Name
CS: Content Store
FIB: Forwarding Information Base
PIT: Pending Interest Table
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Torsten Braun: Service-Centric Networking
CCN Model:
Match in Forwarding Information Base
CS
FIB
PIT
Name
CS: Content Store
FIB: Forwarding Information Base
PIT: Pending Interest Table
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Torsten Braun: Service-Centric Networking
CCN Model: Match in Pending Interest Table
Name
CS
FIB
PIT
x
CS: Content Store
FIB: Forwarding Information Base
PIT: Pending Interest Table
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Torsten Braun: Service-Centric Networking
Content Distribution
/unibe.ch/braun/lecture/20100405
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Torsten Braun: Service-Centric Networking
Naming
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Any kind of names are possible → flexible naming
Naming approaches
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2 phases: mapping of ID to locator, routing to data source
1 phase: direct ID-based routing to data source
Examples
— /unibe.ch/braun/lecture/20100405
— /weather/greece/20110906
— CCNx support for simple operations
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%C1.org.ccnx.frobnicate~1~37
command in the namespace org.ccnx
operation is frobnicate, which takes 1 and 37 as arguments
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Torsten Braun: Service-Centric Networking
Routing
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Longest Prefix Match Routing (as in IP)
But: different FIB entry semantics
— IP: IP address prefix can be reached via an outgoing interface for
an existing FIB entry
— CCN: content name prefix might be reached via an outgoing
interface for an existing FIB entry
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FIB entries should be populated proactively for known content.
Alternatively, searching for content, e.g., using broadcasting
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Torsten Braun: Service-Centric Networking
Content-Centric Networking
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Advantages
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Automatic content distribution
< 1 round-trip-time
Minimization of latency
Minimization of bandwidth (cf. multicast)
Local congestion control
Built-in security
Drawbacks
— Routing (and naming) as open issue
— Lacking support of flexible services
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Torsten Braun: Service-Centric Networking
Service-Centric Networking (SCN)
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CCN is content-centric and encodes a few operations on content
as extensions of names.
Proposal: Service-Centric Networking
— Extension of content-centric networking to support services,
possibly operating on content.
— Description of a service using content naming scheme,
e.g., /google.com/file-service
— Service request to invoke a service in Interest message
— Service response in Data message
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Services
— Infrastructure services, e.g., cloud computing services
— Client-oriented services, e.g., web services, remote procedure calls
— Continuous content retrieval and streaming services,
e.g., A/V conferencing, streaming
— In-network processing, e.g., sensor data aggregation and fusion
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Torsten Braun: Service-Centric Networking
Advantages of SCN
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Low delay and efficient network resource utilization due to
— No need for separate service lookup and service registry
— Caching of service data; extended caching of multimedia data
(transcoding) or sensor data (data fusion)
— Optimized service selection
(considering load, delay metrics for service request routing)
— Location-based services
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Torsten Braun: Service-Centric Networking
Uniform Naming for Services (Functions)
and Content (Data)
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Services perform (data) processing and are represented by
functions to be invoked. Content stores for data.
Service-centric networking should support both data and functions.
Object-orientated programming paradigm integrates both
functions and data into objects.
Method calls among objects to invoke functions.
Proposal: Object names for both services (functions) and content
(data), e.g.,
— /youtube.com/rendering
— /unibe.ch/braun/lecture/20100405
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Advantages of object-oriented approach
— Uniform naming
— Services can be implemented as a set of cooperating objects
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Torsten Braun: Service-Centric Networking
SCN Object Types
read
content
data
function1
read
function2
function1
function3
content
data
function2
1: Content Object
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2: Service Object
3: Content/Service Object
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Torsten Braun: Service-Centric Networking
Example: Audio/Video Mixing
mix
client
read write
video
1
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read write
video
2
read
write
video
3
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Torsten Braun: Service-Centric Networking
Service-Centric Network
SCN router
Service request/response
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Torsten Braun: Service-Centric Networking
Continuous Data Flows
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CCN Interest messages must be continuously submitted for
continuous data flow, e.g., VoIP, streaming, sensor information
Option: deployment of states (cf. gradients in directed Diffusion)
to support continuous forwarding
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Torsten Braun: Service-Centric Networking
Moblity and DTN Support
CCN: Forwarding of Data is based on PIT entries, no usage in mobile networks
Interests
Origin of Data
Interest
/youtube.com/movies/
crazystupidlove
me
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/unibe.ch/braun/talks/spice
user1
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Encounter
xxx
Possible message exchange at encounter
1. Exchange of interests
2. Exchange of relevant data
Possibly two phases: own vs. others’ interests
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Torsten Braun: Service-Centric Networking
CCNx in Mobile Environments
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Benefits:
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Broadcast property of the wireless medium
Flexible communication  routes not important
No beaconing required
Reduced average delay / less hops due to possible caching
Problems: challenging evaluation
— Repeatability
— Unpredictable wireless environments
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Torsten Braun: Service-Centric Networking
Experimentation Platform
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Torsten Braun: Service-Centric Networking
Conclusions and Outlook
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Service-Centric Networking as a new paradigm extending
content-centric networking using an object-oriented naming
concept to be integrated into DTN environments
Open Issues
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Implementation architectures
Service management and composition
Routing
Service parameter support
Mobile ad-hoc networks
Delay-tolerant networks
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Torsten Braun: Service-Centric Networking
Further Reading
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Torsten Braun, Volker Hilt, Markus Hofmann, Ivica Rimac,
Moritz Steiner, Matteo Varvello:
Service-Centric Networking,
Fourth International Workshop on the Network of the Future ,
Kyoto, Japan, June 9, 2011
Thomas Staub, Reto Gantenbein, Torsten Braun:
VirtualMesh: an emulation framework for wireless mesh and
ad hoc networks in OMNeT++, SIMULATION, Vol. 87, No. 12, p.66-81, January, 2011
see rvs.unibe.ch/research/publications
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Torsten Braun: Service-Centric Networking
Thanks for your attention !
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rvs.unibe.ch/research
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