Information-Centric Networking in Wireless/Mobile Networks
1. IFIP/ACM LANC 2012
7th Latin America Networking Conference
Information-Centric Networking in
Wireless/Mobile Networks
Torsten Braun, Universität Bern, Switzerland
braun@iam.unibe.ch, cds.unibe.ch
2. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Overview
> Future Internet
> Information-Centric Networking (ICN)
— ICN Approaches, e.g., CCN and PSI
— Service-Centric Networking
— ICN and Cloud Computing
> ICN in Wireless / Mobile Networks
— Mobility
— Delay/Disruption-Tolerant and Opportunistic Networks
— Network Coding and Energy Efficiency
> Conclusions
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3. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Future Internet
> The current Internet is based on principles
of the 1960s with the main purpose to
interconnect large computers.
> Today, Internet users are mainly interested
in retrieving content and accessing services
with increasing demand for mobility&security
> Increasing bandwidth demand due to
— (personalized) multimedia data streams
— Cloud computing and storage,
visualization on (mobile / high-resolution) end systems
— Huge amounts of data from measurements and scientific
experiments
— Internet of Things, Internet of Services, …
> New approaches, e.g., Information-Centric Networking,
need more research, development, testing etc.
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4. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Motivation for
Information-Centric Networking
> Today’s network traffic is dominated by information retrieval
rather than point-to-point communication between machines
or humans.
> 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 aspects of
the same problem:
— Wires move information in space.
— Memories move information in time.
> Future communications architecture should unify both issues.
> Flash crowds are difficult to avoid in IP-based networks.
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5. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Traditional Web Retrieval / Web Services
search engine /
service registry
user’s end system
web server /
web service
DNS server
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6. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Key Principles and Functions of ICN
> Naming of content rather than hosts/interfaces
— Content independent of devices that store it
— Naming is location independent (mobility support !)
> Receivers (subscribers) request content.
> Senders (publishers) advertise and deliver content.
> Receivers and senders do not have to be aware of each
other and are decoupled in time.
> Functions needed
— Name resolution to match subscriptions and publications
— Routing and path formation
— Forwarding content from publisher to subscriber
[Pentikousis, K.; Chemouil, P.; Nichols, K.; Pavlou, G.; Massey, D.; "Information-centric networking [Guest editorial]",
IEEE Communications Magazine, vol.50, no.7, pp.22-25, July 2012
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7. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Content Distribution with ICN
/unibe.ch/braun/lecture/20120405
1
2 3
4 5 6 7
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8. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Naming Approaches
> Human-readable, hierarchical names
— supports aggregation
— needs coordination
— Example: CCN
> Flat (self-certifying) names
— Often based on hashing content name and/or owner’s public key
— Aggregation more difficult but more flexible.
— Examples: PSI, NetInf
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9. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Name Resolution and Data Transport
> Decoupled
— Name resolution and data transport are independent of each
other, cf. DNS, with possibly different nodes for resolution and
data transport
— allows different, possibly already existing transport mechanisms,
also multi-path
— Examples: PSI, NetInf
> Coupled
— Nodes for both name resolution and data transport with inverse
data path compared to search path
— rather disruptive technology
— Local routing procedures advantageous in case of short link
disruptions
— Examples: CCN, NetInf
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10. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Content-Centric Networking (CCN)
> Combination of content lookup and message routing
> Idea: describe the user’s 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
> Hierarchical content names
— Example: /unibe.ch/braun/lecture/20120405
> Related Projects
— NDN = Named Data Networking, www.named-data.net
— CCNx = Open Source Core Software Project for
Content-Centric Networking, www.ccnx.org
Van Jacobson, Diana K. Smetters, James D. Thornton, Michael F. Plass, Nicholas H. Briggs, and Rebecca L. Braynard:
Networking named content, 5th international conference on Emerging networking experiments and technologies (CoNEXT
'09). ACM, New York, NY, USA, 1-12.
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11. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
IP Model
FIB
FIB: Forwarding Information Base
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12. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Interest Message Processing in CCN
1. Longest prefix match on content name in Content Store:
returning data and discarding Interest
2. Pending Interest Table match:
adding request to PIT and discarding Interest
3. Forwarding Information Base match:
forwarding of Interest towards data
— FIB population by announcements of content availability
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13. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Match in Content Store
CS FIB
Name Data
PIT
Name
CS: Content Store
FIB: Forwarding Information Base
PIT: Pending Interest Table
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14. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Match in Forwarding Information Base
CS FIB
PIT
Name
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15. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Match in Pending Interest Table
Name
CS FIB
PIT
x
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16. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
CCN Naming
> Hierarchical naming allowing aggregation
> Examples
— /unibe.ch/braun/lecture/20120405
— /unibe.ch/N10/R306/Projector
> Support for simple operations
— %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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17. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
IP / CCN Hour-Glass Models
WWW, email, VoiP browser, chat
HTTP, SMTP, RTP file, stream
TCP, UDP security
content
chunks
IP
Strategy
Ethernet, WiFi TCP, P2P, Broadcast
Fiber, radio, copper Fiber, radio, copper
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18. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
CCN Routing
> Longest Prefix Match Routing (as in IP)
> FIB entries should be populated proactively for known content.
> Alternatively, searching for content, e.g., using flooding
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19. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
CCN Transport
> Stateless operation with receiver control
> Reliability by local retransmissions in strategy layer
> Hop-by-hop flow control
> Sequence numbers in names
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20. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
CCN Security
> Signing of names and data in each packet
> Denial-of-Service attacks are difficult:
Multiple Interests → only 1 data packet per Interest
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21. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
CCN Evaluation
> Advantages
— Automatic content distribution
— < 1 round-trip-time
— Minimization of latency
— Minimization of bandwidth
— Local congestion control
— Built-in security
> Challenges
— Routing protocols
— Hierarchical naming
— Source mobility
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22. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Publish-Subscribe Internet (PSI) Naming
> Information items = files, streams, services
> Each information item has its own name.
> Names are unique (SID,RID) pairs
— Rendezvous Identifier (RID)
SId1 SId2
– Fixed-length, (flat) bit string
– produced by application
SId1 SId1 SId2
specific function, e.g., hashing
— Scope Identifier (SID) RId3
RId4 RId1 RId2 RId3
– Containers for information SId3
items
– Basis for access control RId1 RId2 RId3
> Scope hierarchy with information belonging to different scopes.
> www.fp7-pursuit.eu
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23. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
PSI Network Primitives
> Subscribe
— used to express interest in information items
— Users can subscribe to information items or scopes.
(SID/RID) must be known.
> Publish
— used to announce information items
— sent if information items have been requested
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24. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
PSI Operation
> Information producer publishes information item to rendezvous
system consisting of rendezvous points.
> Rendezvous points are responsible for certain scopes.
> Information consumer subscribes to information item.
> Rendezvous system matches announcements and subscriptions
and triggers delivery from information producer to information
consumer, e.g. using OpenFlow
> Various caching strategies: on-path, off-path, replication
publication path establishment
subscription
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25. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Service-Centric Networking (SCN)
> ICN/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 (response) in Interest (Data) message
> Services
— Infrastructure services, e.g., cloud computing services
— Client-oriented services, e.g., web services
— Continuous content retrieval and streaming services,
e.g., A/V conferencing, streaming
— Event services, e.g., exceeding sensor data thresholds or stock data
— In-network services, e.g., aggregation and filtering of sensor data
Braun, T.; Hilt, V.; Hofmann, M.; Rimac, I.; Steiner, M.; Varvello, M.: Service-Centric Networking, 2011 IEEE
International Conference on Communications Workshops (ICC), pp.1-6, Kyoto, 5-9 June 2011
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26. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Service-Centric Network
SCN network
SCN router
Service request/response
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27. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Advantages of SCN
> No service lookup and service registry
> Caching of service data
> Extended caching of multimedia data (transcoding)
> Location-based services
> Optimized service selection
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28. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Uniform Naming for Services (Functions)
and Content (Data)
> 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/20120405
> Advantages of object-oriented approach
— Uniform naming
— Services can be implemented as a set of cooperating objects
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29. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
SCN Object Types
function1
read
read
function2
content content
function1
data data
function3
function2
1: Content Object 2: Service Object 3: Content/Service Object
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30. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Example: Video Rendering
render
client
read write read write read write
video- video- video-
file1 file2 file3
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31. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Example: Real-time Audio Conferencing
Sent audio Echo Trans-
Mixing
data cancellation coding
Received audio data
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33. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
ICN and Cloud Computing
> ICN might be used to
— find/call cloud services (computation, storage)
— deploy cloud services
— support caching of cloud data
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34. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Upcoming EU FP7 Integrated Project:
Mobile Cloud Network
> Integration of
— Radio Access Network
— Mobile Core Network
— Data Centre (computing, storage, applications)
into (decentralized) cloud computing infrastructure (management!)
> Advantages: elasticity, costs, performance, e.g., by
exploitation of user location for service provisioning → Follow Me Cloud
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36. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Benefits of ICN in Wireless/Mobile Networks
> Broadcast property of wireless medium
→ single Interest to many neighbor nodes
> No beaconing required to learn about neighbor nodes
> Reduced delay and network load due to possible caching
> Request/Response based routing in mobile ad-hoc networks
(MANETs) could be replaced by Interest/Data exchange,
cf. Directed Diffusion
> Support of short mobile nodes’ encounters
> ICN architectures inherently support receiver mobility !
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37. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Source Mobility
> Problem
— Finding a source’s location at the beginning of and when source is moving during
communication.
> Solutions
— Routing-based approaches
– (Proactive) updating of routing tables in case of moving sources
→ issues on scalability and convergence
— Indirection
– (Home) agent forwards all Content Requests to mobile source, cf. Mobile IP.
– This requires location-based identifiers, cf. location/identity separation.
— Resolution
– Receiver requests location-based identifier for a content name specified in a Content
Request.
– Approach adds resolution phase and requires resolution entities in visited networks.
> Conclusions and Suggestions
— Both content names and locators might be needed to efficiently support ICN
source mobility.
— Flexible use of content names / locators
— Possibly late binding of content names and locators
Vasilios Siris:, Torsten Braun: Content-Centric Networking Architectures for Moving Objects, COST Action
IC0906, STSM Report, 2012, http://cost-winemo.org/
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38. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
CCN in Delay/Disruption-Tolerant (DTN)
and Opportunistic Networks
Name Origin of Data
Interest
/feeds.sf.tv/podcast/10vor10 me -
/youtube.com/movies/ mydaughter -
DesperateHousewives Encounter
… … …
/unibe.ch/braun/lecture/ me, os.mpg
OperatingSystems mystudent
… … …
Possible message exchange at encounter
1. Exchange of interests, possibly with priority of own / friends’ interests
2. Exchange of relevant data
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39. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Content-Centric Networks and
DTN/Opportunistic Networks
> Content-Centric Networks and Delay/Disruption-Tolerant
Networks seem to be a good match.
— No needs for beacons and neighbour lists
— Exploitation of wireless broadcast media
— Efficient exchange of Interests and Data
> Publish / Subscribe approaches might be less beneficial here.
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40. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Network Coding and CCN
> Regular case:
— 4 Interests + 4 Data
messages Data A
> Network Coding:
— 3 Interests + 3 Data Interest B
messages
Interest A B
> Problem: Naming Data B
> Proposal: Encapsulation
Data A B
Alexander Striffeler: Interest A
Network Coding in mobile CCN,
Bachelor Thesis at Universität Bern
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41. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Network Coding of CCN Data Messages
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42. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Energy Efficiency and CCN
> ICN can reduce packet transmissions on links
> This comes at the expense of additional memory needed in
caches.
> Assumptions for power usage
— DRAM: 3 W/GB
— Hard disk: 0.02 W/GB
— SSD: 0.01 W/GB
— Energy for transmission: 15 W/Gbps = 15 Joules/Gigabit
> Analytical evaluation in example scenarios, options
— no CCN support at all
— CCN support in CCN router
Tuan Anh Trinh, Torsten Braun: Energy Efficiency in Information-Centric Networking, COST Action IC0804, STSM
Report, 2012, http://www.irit.fr/cost804/
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44. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Energy Efficiency and CCN
> Required energy for serving K requests from original content source:
Eread_from_source = K * N * link_energy * datasize.
> Required energy for serving request from cache:
Eread_from_cache = K * M * link_energy * datasize + lifetime_in_cache * storage_power *
datasize
> ICN can help to decrease energy costs, if Eread_from_cache < Eread_from_source
→ (N - M) * link_energy / storage_power > lifetime_in_cache / K
— lifetime_in_cache: lifetime a content object is usually stored in the cache
— storage_power: power required to store a certain amount of data
— link_energy: energy to transport a certain amount of data across a link
> lifetime_in_cache / K = inter_access_time (avg. time between two content accesses)
> access frequency f = 1/inter_access_time
→ f > storage_power / ((N-M) * link_energy)
> Example
— Link energy = 15 Joules / Gigabit = 120 Joules / GB
— Storage power = 3 W/GB for storage in DRAM
— M = 1, N = 11
— ICN only reduces energy consumption if f > (3 W / GB) / ((11-1) * (120 Joules / GB))
= 1 / 400 s
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45. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Conclusions
> Information-Centric Networking attracts huge research interest.
> ICN has potential to
— save bandwidth
— reduce delay
— save energy
— support receiver mobility
— operate efficiently in wireless networks
— support DTN and opportunistic networks
> Challenges
— storage in routers
— routing strategies
— source mobility
— more general services
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46. Torsten Braun: Information-Centric Networking in Wireless/Mobile Networks
Thank You for Your Attention !
> braun@iam.unibe.ch
> http://cds.unibe.ch
> http://www.slideshare.net/torstenbraun
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