Torsten Braun Universität Bern [email protected] rvs.unibe.ch
description
Transcript of Torsten Braun Universität Bern [email protected] rvs.unibe.ch
Workshop at Space Internetworking Center (SPICE), Xanthi
Delay Tolerant Networking and Content/Service-Centric Networking
Torsten BraunUniversität [email protected]
Torsten Braun: Service-Centric Networking
2
Overview
> Computer Networks and Distributed Systems @ U Bern
> Content- and Service-Centric Networking in Mobile and Delay-Tolerant Networks
> Conclusions and Outlook
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
3
Research Projects @ Computer Networks and Distributed Systems
> Opportunistic Routing forHighly 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
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
4
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
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
5
EU FP7 Wisebed (until 6/2011): WSN Testbed Management System
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
6
TARWIS Experiment Configuration
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
7
Recent WSN Experiments
> 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
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
8
Motivation for Content-Centric Networking
> 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]
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
9
Traditional Web Retrieval / Web Services
Xanthi, September 6, 2011
web server / web service
DNS server
search engine /service registry
user’s end system
Torsten Braun: Service-Centric Networking
10
Related Work
> Peer-to-Peer Networks— Construction of overlay networks— Content / service discovery,
e.g., using distributed hash tables, flooding, random walks, etc. > Web Caching
— Providing content for local users> Content Distribution Networks
— Routing and redirection of HTTP requests— Cache management
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
11
Content-Centric Networking (CCN)
> [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
> Hierarchical content names— Example: /unibe.ch/braun/lecture/20100405
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
12
Related Projects
> 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
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
13
IP Model
Xanthi, September 6, 2011
FIB
FIB: Forwarding Information Base
SRC
DST
Torsten Braun: Service-Centric Networking
14
Processing of Interest Message in CCN
1. 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— FIB population by announcements of content availability
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
15
CCN Model: Match in Content Store
Xanthi, September 6, 2011
FIB
CS: Content StoreFIB: Forwarding Information BasePIT: Pending Interest Table
Name
CS
Name
Data
Data
Name
PIT
Torsten Braun: Service-Centric Networking
16
CCN Model: Match in Forwarding Information Base
Xanthi, September 6, 2011
FIBCS
Name
PIT
CS: Content StoreFIB: Forwarding Information BasePIT: Pending Interest Table
Torsten Braun: Service-Centric Networking
17
CCN Model: Match in Pending Interest Table
Xanthi, September 6, 2011
FIBCS
Name
PIT
x
CS: Content StoreFIB: Forwarding Information BasePIT: Pending Interest Table
Torsten Braun: Service-Centric Networking
18
Content Distribution
Xanthi, September 6, 2011
/unibe.ch/braun/lecture/20100405
1
32
4 5 76
Torsten Braun: Service-Centric Networking
19
Naming
> Any kind of names are possible → flexible naming> Naming approaches
> 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
– %C1.org.ccnx.frobnicate~1~37– command in the namespace org.ccnx– operation is frobnicate, which takes 1 and 37 as arguments
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
20
Routing
> 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
> FIB entries should be populated proactively for known content.> Alternatively, searching for content, e.g., using broadcasting
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
21
Content-Centric Networking
> Advantages— 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
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
22
Service-Centric Networking (SCN)
> 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
> 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
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
23
Advantages of SCN
> 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
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
24
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/20100405
> Advantages of object-oriented approach— Uniform naming— Services can be implemented as a set of cooperating objects
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
25
SCN Object Types
contentdata
read
1: Content Object 2: Service Object
contentdata
read
3: Content/Service Object
function3function1
function2
function1
function2
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
26
Example: Audio/Video Mixing
Xanthi, September 6, 2011
mix
video1
read
client
video2
read
video3
read writewritewrite
Torsten Braun: Service-Centric Networking
27
Service request/response
SCN router
Service-Centric Network
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
28
Continuous Data Flows
> 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
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
29
Moblity and DTN Support
Interests Origin of Interest
Data
/youtube.com/movies/ crazystupidlove
me -
… …
/unibe.ch/braun/talks/spice user1 xxx
… …
Xanthi, September 6, 2011
Encounter
Possible message exchange at encounter1. Exchange of interests 2. Exchange of relevant dataPossibly two phases: own vs. others’ interests
CCN: Forwarding of Data is based on PIT entries, no usage in mobile networks
Torsten Braun: Service-Centric Networking
30
CCNx in Mobile Environments
> Benefits:— 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
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
31
Experimentation Platform
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
32
Conclusions and Outlook
> 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— Implementation architectures— Service management and composition— Routing— Service parameter support— Mobile ad-hoc networks— Delay-tolerant networks— …
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
33
Further Reading
> 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. 1-2, p.66-81, January, 2011
> see rvs.unibe.ch/research/publications
Xanthi, September 6, 2011
Torsten Braun: Service-Centric Networking
34
Thanks for your attention !
> rvs.unibe.ch/research
Xanthi, September 6, 2011