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Short Description
CCN-lite is a reduced and lightweight implementation of the CCNx protocol
Full Description

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CCN-lite is a reduced and lightweight -- yet functionally
interoperable -- implementation of the CCNx and NDN protocols. It covers:

CCN-lite supports multiple platforms, including:

  • Linux and OS X user space
  • Linux kernel
  • Android
  • Arduino and RFduino
  • OMNeT++

CCN-lite is meant as a code base for class room work, experimental
extensions and simulation experiments. The ISC license makes it an
excellent starting point for commercial products.

CCN-lite has been included in the RIOT operating system for the
Internet of Things (IoT): http://www.riot-os.org/

<a name="toc"></a>

Table of Contents

  1. Getting started
  2. Rationale for CCN-lite
  3. Extensions
  4. CCN-lite supported platforms
  5. Command line tools
  6. Useful links
  7. Tentative roadmap
  8. Changelog
  9. Credits

<a name="gettingstarted"></a>

1. Getting started

To start right now with CCN-lite visit the tutorial. It
covers installation on Unix and basic functionality of CCN-lite.

For more information about CCN-lite supported platforms and how to build, see
CCN-lite supported platforms. The source code of CCN-lite is
available on GitHub, either the
master branch or dev-master. If you found a bug or want to report a problem
with CCN-lite, feel free to
create an issue on GitHub - we
appreciate it!

<a name="rationale"></a>

2. Rationale for CCN-lite

The original motivation in 2011 for creating CCN-lite was that PARC's CCNx
router software had grown huge. CCN-lite provides a lean alternative for
educational purposes and as a stepping stone. It's for those who want a simple
piece of software for experimentation or own development, but who do not need
all features of the full thing.

This brings the interesting question of interoperability: What minimum
functionality is necessary in order to participate in a CCNx network? With
CCN-lite, we have made a first attempt at identifying that set, but we are aware
that this set might be incomplete, or may change depending on how CCNx evolves.
We consider this question of "sufficient CCNx functionality" to be of
engineering and academic interest of its own and welcome contributions from
everybody.

Hence, with CCN-lite, we did a race-to-the-bottom and strived for a kind of
"Level-0" interoperability. Level-0, as we understood it, covers:

  • ccnb encoding of messages (or any other encoding flavor, including the TLV variants)
  • PIT and FIB, basic CCN data structures
  • longest and exact prefix matching for basic CCN operations,
    including minsuffixcomp und maxsuffixcomp handling
  • matching of publisher's public key to fight cache poisoning
  • nonce and/or hop limit tracking to avoid loops as a minimal safeguard

As an interoperability goal we set for ourselves the threshold that the CCN-lite
software must be able to route at the CCN level between fully fledged CCNx
forwarders. Of course, this is a moving target, but we regularly use our tools
to interface with the NDN testbed, for example.

We deliberately do not cover in our CCN-lite code:

  • sophisticated data structures for performance optimizations
  • exclusion filtering in interests
  • all TCP connectivity and the old CCNx cmd line utilities that have TCP
    hardwired into them
  • crypto functionality which is not our prime concern (yet)
  • repository functionality, SYNC server, ...

A second reason to create CCN-lite was the software license (the original CCNx
project picked GNU, but NDN also has chosen this path) where we prefer a
Berkeley Software Distribution style of "do whatever you want" as we believe
that this will help adopting CCN technology. Therefore, CCN-lite is released
under the ISC license. We have learned that several companies have picked up
CCN-lite for their internal experiments, so we think our license choice was
right.

What you get with CCN-lite is:

  • a tiny CCNx core (1000-2000 lines of C suffice)
  • multiple platform support
  • partially interoperable management protocol implementation
  • a simple HTTP server to display the relay's internal configuration
  • plus some interesting extensions of our own, see the next section.

<a name="extensions"></a>

3. Extensions

In several selected areas we have started our own contributions that are now
part of CCN-lite:

  • Named functions for letting clients express results instead of accessing
    only raw data. See also the use of Scala
    to host function execution and to interface to a NFN network.

  • Experimental RPC functionality for letting neighbors mutually invoke
    functions, which could be the starting point both for network management
    functionality and for data marshalling (of interests and data objects) using
    the TLV encoding.

  • Clean packet scheduler support at chunk level as well as packet or fragment
    level (symbol USE_SCHEDULER)

  • Packet fragmentation and lost packet detection support for running the CCNx
    protocol natively over Ethernet (symbol USE_FRAG). This is somehow outdated
    and waits for protocol specs to emerge.

Other features that you can switch on and off at compile time are:

Featue Description
USE_CCNxDIGEST Enable digest component, requires crypto lib.
USE_CHEMFLOW Experimental scheduler based on chemical networking, source not included.
USE_DEBUG Basic data structure dumping.
USE_DEBUG_MALLOC Compile with memory armoring.
USE_DUP_CHECK Check for duplicate nonces.
USE_ECHO Enable an echo prefix, returning the current time.
USE_LINKLAYER Talk to Ethernet, W-LAN, 802.15.4 devices, raw frames.
USE_FRAG Enable fragments, to run CCNx over Ethernet.
USE_HMAC256 Enables hash-based authentification codes.
USE_HTTP_STATUS Provide status info for web browsers.
USE_IPV4 Enable IP support.
USE_LOGGING Enable log messages.
USE_KITE Routing along the return path, not yet supported.
USE_MGMT React to CCNx management protocol messages.
USE_NACK NACK support for NFN.
USE_NFN Enable named function networking.
USE_NFN_NSTRANS Namespace translation for NFN.
USE_NFN_MONITOR Message logging for nfn-scala.
USE_SCHEDULER Rate control at CCNx msg and fragment level.
USE_SIGNATURES Authenticate management messages.
USE_STATS Enable statistics.
USE_SUITE_* Enable a specific protocol: CCNB, NDN2013, CCNx2014, IOT2014, LOCALRPC or CISCO2015.
USE_UNIXSOCKET Add UNIX IPC to the set of interfaces.

The approach for these extensions is that one can tailor a CCN forwarder to
including only those features really necessary. We have strived to make these
choices as orthogonal as possible and invite you to attempt the same for your
additions.

<a name="platforms"></a>

4. CCN-lite supported platforms and how to compile

CCN-lite currently supports five platforms. To find out how to install and use
CCN-lite on each individual platform, refer to the platform-specific readme
files:

Additionally, CCN-lite has a pre-built Dockerfile to enable the usage of
Docker with CCN-lite. See the
Docker-specific readme file for more information.

Named function support

If you want named function support (NFN), define an environment variable at the
shell level before invoking make:

export USE_NFN=1
make clean all

If you want both NFN and NACK support, define an additional environment variable
before invoking make:

export USE_NFN=1
export USE_NACK=1
make clean all

CCN-lite-minimalrelay

As an exercise in writing the least C code possible in order to get a working
NDN forwarder, CCN-lite includes ccn-lite-minimalrelay.c. It has all extra
features disabled and only provides UDP connectivity. But hey, it works! And it
really is lean, looking at the lines of C code:

 435 ccn-lite-minimalrelay.c
1010 ccnl-core.c
 701 ccnl-core-fwd.c    // only partially needed
1090 ccnl-core-util.c
 647 ccnl-pkt-ndntlv.c  // only partially needed

 316 ccnl-core.h
 197 ccnl-defs.h
 104 ccnl-pkt-ndntlv.h

<a name="lof"></a>

5. Command line tools

The main command line tools and their corresponding source file that are shipped
with CCN-lite are the following:

Tool Description
ccn-lite-relay.c CCN-lite forwarder: user space.<br /> This file is compiled into three executables, depending on compile time environment flags: <ul><li>ccn-lite-relay</li><li>ccn-nfn-relay</li><li>ccn-nfn-relay-nack</li></ul>
ccn-lite-lnxkernel.c CCN-lite forwarder: Linux kernel module
util/ccn-lite-ctrl.c Command line program running the CCNx management protocol (over Unix sockets). Used for configuring a running relay either running in user space or as a kernel module.
util/ccn-lite-ccnb2xml.c Simple CCNB packet parser
util/ccn-lite-cryptoserver.c Used by the kernel module to carry out compute intensive crypto operations in user instead of kernel space.
util/ccn-lite-fetch.c Fetches both a single chunk content or a series of chunks for larger named data. Only the content is returned without any protocol bytes.
util/ccn-lite-mkC.c Simple content composer, to stdout, without crypto.
util/ccn-lite-mkF.c Simple tool to split a large file into a fragment series.
util/ccn-lite-mkI.c Simple interest composer, to stdout.
util/ccn-lite-peek.c Simple interest injector waiting for a content chunk, can also be used to request named-function results.
util/ccn-lite-pktdump.c Powerful packet dumper for all known packet formats. Output is in hexdump style, XML or content only.
util/ccn-lite-produce.c Creates a series of chunks for data that does not fit into a single PDU.
util/ccn-lite-rpc.c Send an RPC request and return the reply.
util/ccn-lite-simplenfn.c Simplified interface to request named-function results.
util/ccn-lite-valid.c Demo application for validating a packet's signature.

<a name="links"></a>

6. Links:

<a name="roadmap"></a>

7. Tentative roadmap

Work has started for the next release 0.4 (Dec 2015?), where the focus
should be on the following areas:

  • Manifests
  • Security (key management, signed computations and trust schematas)
  • Data access control
  • Better selector support for NDN
  • RIOT re-integration

<a name="changelog"></a>

8. Changelog

Release 0.3.0 (Jul 2015)

  • Demonstrated interoperability with now-stabilized CCNx1.0, which can run
    side-by-side with NDN in a single CCN-lite relay
  • OMNeT++ integration is back, as it has been requested many times
  • New platforms and transport:
    • Arduino and RFduino
    • Android and Bluetooth Low Energy
  • New functionality: "begin-end" fragmentation for CCNx1.0 and NDN
  • Improved build quality for Ubuntu and OSX
  • Improved READMEs all over the release, easy tutorials
  • Named Function Networking (NFN) over NDN now has Python bindings to make the
    publishing of named functions easier.

<a name="credits"></a>

9. Credits

Release 0.3.0 (Jul 2015)

Code contributions:

Lukas Beck
Christopher Scherb
Manolis Sifalakis
Christian F. Tschudin

Feedback and other contributions:

Fateh Al-Mufti
Frederik Brix
Patrick Buder
Daniel Federau
Ilir Fetai
Nenad Kokeza
David Kordsmeier
Dima Mansour
Marc Mosko
Mihai Daniel Rapcea
Fabian Rauschenbach
Yanick Salzmann
Maarten Schenk
Urs Schnurrenberger
Marco Suter
Marc-Andrea Tarnutzer
Marco Dieter Vogt
Akan Yilmaz

Release 0.2.0 (Dec 2014)

Code contributions:

Basil Kohler
Christian Mehlis
Massimo Monti
Christopher Scherb
Manolis Sifalakis
Christian F. Tschudin

Code and documentation feedback:

Samuel Bader
Christoph Betschart
Nore Derguti
Ralph Droms
Wilson A. Eghonghon
Daniel Federau
Ralph Gasser
Cedric Geissmann
Rasa Liebfried
Dario Maggi
Frank Müller
Marko Obradovic
Michaja Pressmar
Mihai D. Rapcea
Urs Schnurrenberger
Thomas Simonsen
Alexander Stiemer
Ziba Tavassoli
Simon Wang
Mario Weber

Release 0.1.0 (Jul 2013)

Code contributions:

Stefan Braun
Pierre Imai
Basil Kohler
Thomas Meyer
Massimo Monti
Christopher Scherb
Manolis Sifalakis
Christian F. Tschudin

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