| .. _ndn-autoconfig: |
| |
| ndn-autoconfig |
| ============== |
| |
| Synopsis |
| -------- |
| |
| **ndn-autoconfig** [**-h**] [**-V**] [**-c** *file*] [**-d**] |
| |
| Description |
| ----------- |
| |
| Client tool to run :ref:`NDN hub discovery procedure`. |
| |
| Options |
| ------- |
| |
| ``-d`` or ``--daemon`` |
| Run ndn-autoconfig in daemon mode. In this mode, the auto-discovery procedure is re-run |
| hourly or when a network change event is detected. |
| |
| NOTE: if connection to NFD fails, the daemon will be terminated. |
| |
| ``-c FILE`` or ``--config=FILE`` |
| Use the specified configuration file. If `enabled = true` is not specified in the |
| configuration file, no actions will be performed. |
| |
| ``--ndn-fch-url=URL`` |
| Use the specified URL to find the closest hub (NDN-FCH protocol). If not specified, |
| ``http://ndn-fch.named-data.net/`` will be used. Only ``http://`` URLs are supported. |
| |
| ``-h`` or ``--help`` |
| Print help message and exit. |
| |
| ``-V`` or ``--version`` |
| Show version information and exit. |
| |
| .. _NDN hub discovery procedure: |
| |
| NDN hub discovery procedure |
| --------------------------- |
| |
| When an end host starts up, or detects a change in its network environment, it MAY use |
| this procedure to discover a NDN router, in order to gain connectivity to |
| `the NDN research testbed <https://named-data.net/ndn-testbed/>`__. |
| This procedure can discover either an NDN router in the local network, or a NDN testbed |
| gateway router (commonly known as a "hub"). |
| |
| Overview |
| ^^^^^^^^ |
| |
| This procedure contains four methods to discover a NDN router: |
| |
| 1. Look for a local NDN router by multicast. |
| This is useful in a home or small office network. |
| |
| 2. Look for a local NDN router by DNS query with default suffix. |
| This allows network administrator to configure a NDN router in a large enterprise network. |
| |
| 3. Find closest hub by sending an HTTP request to NDN-FCH server. |
| |
| 4. Connect to the home hub according to user certificate. |
| This ensures connectivity from anywhere. |
| |
| After connecting, two prefixes will be registered toward the router: |
| |
| - ``/`` --- this allows application communication |
| - ``/localhop/nfd`` --- this informs NFD-RIB that there is connectivity to a router |
| |
| Stage 1: multicast discovery |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| |
| Request |
| +++++++ |
| |
| The end host sends Interest ``/localhop/ndn-autoconf/hub`` over a multicast face. |
| |
| Response |
| ++++++++ |
| |
| A producer app on the router answers this Interest with a Data packet that contains a |
| ``Uri`` TLV element. The value of this element is the FaceUri for the router, such as |
| a UDP tunnel. |
| |
| Stage 2: DNS query with default suffix |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| |
| Request |
| +++++++ |
| |
| The end host sends a DNS query that is equivalent to this command:: |
| |
| dig +search +short +cmd +tries=2 +ndots=10 _ndn._udp srv |
| |
| Response |
| ++++++++ |
| |
| The DNS server should answer with an SRV record that contains the hostname and UDP port |
| number of a nearby NDN router. |
| |
| Stage 3: HTTP Request to NDN-FCH server |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| |
| This stage uses a simple HTTP-based API. For more information about NDN-FCH server, refer |
| to the `NDN-FCH README file <https://github.com/named-data/ndn-fch>`__. |
| |
| Request |
| +++++++ |
| |
| HTTP/1.0 request for the NDN-FCH server URI (`<http://ndn-fch.named-data.net/>`__ by default) |
| |
| Response |
| ++++++++ |
| |
| The HTTP response is expected to be a hostname or an IP address of the closest hub, |
| inferred using IP-geo approximation service. |
| |
| Stage 4: find home router |
| ^^^^^^^^^^^^^^^^^^^^^^^^^ |
| |
| This stage assumes that user has configured default certificate using |
| `<https://ndncert.named-data.net/>`__ as described in `Certification Architecture |
| <https://redmine.named-data.net/attachments/download/23/CertificationArchitecture.pptx>`__. |
| |
| Request |
| +++++++ |
| |
| The end host loads the default user identity (eg. ``/ndn/edu/ucla/cs/afanasev``), and |
| converts it to DNS format. |
| |
| The end host sends a DNS query for an SRV record of name ``_ndn._udp.`` + user identity in |
| DNS format + ``_homehub._autoconf.named-data.net``. For example:: |
| |
| _ndn._udp.afanasev.cs.ucla.edu.ndn._homehub._autoconf.named-data.net |
| |
| Response |
| ++++++++ |
| |
| The DNS server should answer with an SRV record that contains the hostname and UDP port |
| number of the home hub of this user's site. |
| |
| Client procedure |
| ---------------- |
| |
| Stage 1 |
| ^^^^^^^ |
| |
| Send a multicast discovery Interest. |
| If this Interest is answered, connect to the router and terminate auto-discovery. |
| |
| Stage 2 |
| ^^^^^^^ |
| |
| Send a DNS query with default suffix. |
| If this query is answered, connect to the router and terminate auto-discovery. |
| |
| Stage 3 |
| ^^^^^^^ |
| |
| Send HTTP request to NDN-FCH server. |
| If request succeeds, attempt to connect to the discovered hub and terminate |
| auto-discovery. |
| |
| Stage 4 |
| ^^^^^^^ |
| |
| Load default user identity, and convert it to DNS format. |
| If either fails, the auto-discovery fails. |
| |
| Send a DNS query to find home hub. |
| If this query is answered, connect to the home hub and terminate auto-discovery. |
| Otherwise, the auto-discovery fails. |
| |
| Exit status |
| ----------- |
| |
| 0: No error. |
| |
| 1: An unspecified error occurred. |
| |
| 2: Malformed command line, e.g., invalid, missing, or unknown argument. |
| |
| 4: Insufficient privileges. |
| |
| See also |
| -------- |
| |
| :ref:`ndn-autoconfig-server`, :doc:`ndn-autoconfig.conf` |