Eric Newberry
81a9a86305
some documentation updates refs #3809 Change-Id: I0c837a3b8f0f5e5e15d20ba41418bf17660fffb5
86 lines
4.5 KiB
ReStructuredText
86 lines
4.5 KiB
ReStructuredText
NFD Overview
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============
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NDN Forwarding Daemon (NFD) is a network forwarder that implements and evolves together
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with the Named Data Networking (NDN) `protocol
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<https://named-data.net/doc/ndn-tlv/>`__. After the initial release, NFD will become a core
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component of the `NDN Platform <https://named-data.net/codebase/platform/>`__ and will
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follow the same release cycle.
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NFD is developed by a community effort. Although the first release was mostly done by the
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members of `NSF-sponsored NDN project team
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<https://named-data.net/project/participants/>`__, it already contains significant
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contributions from people outside the project team (for more details, refer to `AUTHORS.md
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<https://github.com/named-data/NFD/blob/master/AUTHORS.md>`__). We strongly encourage
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participation from all interested parties, since broader community support is key for NDN
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to succeed as a new Internet architecture. Bug reports and feedback are highly
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appreciated and can be made through `Redmine site
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<https://redmine.named-data.net/projects/nfd>`__ and the `ndn-interest mailing list
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<http://www.lists.cs.ucla.edu/mailman/listinfo/ndn-interest>`__.
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The main design goal of NFD is to support diverse experimentation of NDN technology. The
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design emphasizes *modularity* and *extensibility* to allow easy experiments with new
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protocol features, algorithms, and applications. We have not fully optimized the code for
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performance. The intention is that performance optimizations are one type of experiments
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that developers can conduct by trying out different data structures and different
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algorithms; over time, better implementations may emerge within the same design framework.
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To facilitate such experimentation with the forwarder, the NFD team has also written a
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`developer's guide <https://named-data.net/wp-content/uploads/2016/10/ndn-0021-7-nfd-developer-guide.pdf>`_,
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which details the current implementation and provides tips for extending all aspects of
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NFD.
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NFD will keep evolving in three aspects: improvement of the modularity framework, keeping
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up with the NDN protocol spec, and addition of other new features. We hope to keep the
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modular framework stable and lean, allowing researchers to implement and experiment
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with various features, some of which may eventually work into the protocol spec.
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The design and development of NFD benefited from our earlier experience with `CCNx
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<http://www.ccnx.org>`__ software package. However, NFD is not in any part derived from
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CCNx codebase and does not maintain compatibility with CCNx.
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Major Modules of NFD
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--------------------
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NFD has the following major modules:
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- Core
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Provides various common services shared between different NFD modules. These include
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hash computation routines, DNS resolver, config file, face monitoring, and
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several other modules.
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- Faces
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Implements the NDN face abstraction on top of different lower level transport
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mechanisms.
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- Tables
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Implements the Content Store (CS), the Pending Interest Table (PIT), the Forwarding
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Information Base (FIB), and other data structures to support forwarding of NDN Data
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and Interest packets.
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- Forwarding
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Implements basic packet processing pathways, which interact with Faces, Tables,
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and Strategies.
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+ **Strategy Support**, a major part of the forwarding module
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Implements a framework to support different forwarding strategies. It includes
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StrategyChoice, Measurements, Strategies, and hooks in the forwarding pipelines. The
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StrategyChoice records the choice of the strategy for a namespace, and Measurement
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records are used by strategies to store past performance results for namespaces.
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- Management
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Implements the `NFD Management Protocol
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<https://redmine.named-data.net/projects/nfd/wiki/Management>`_, which allows
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applications to configure NFD and set/query NFD's internal states. Protocol interaction
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is done via NDN's Interest/Data exchange between applications and NFD.
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- RIB Management
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Manages the routing information base (RIB). The RIB may be updated by different parties
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in different ways, including various routing protocols, application's prefix
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registrations, and command-line manipulation by sysadmins. The RIB management module
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processes all these requests to generate a consistent forwarding table, and then syncs
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it up with the NFD's FIB, which contains only the minimal information needed for
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forwarding decisions. Strictly speaking RIB management is part of the NFD management
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module. However, due to its importance to the overall operations and its more complex
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processing, we make it a separate module.
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