| ndn-autoconfig |
| ============== |
| |
| Synopsis |
| -------- |
| |
| :: |
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| ndn-autoconfig |
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| NDN hub discovery procedure |
| --------------------------- |
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| When an end host starts up, or detects a change in its network environment, it MAY use this procedure to discover a local or home NDN router, in order to gain connectivity to `the NDN research testbed <http://named-data.net/ndn-testbed/>`_. |
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| Overview |
| ^^^^^^^^ |
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| This procedure contains three methods to discover a NDN router: |
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| 1. Look for a local NDN router by multicast. |
| This is useful in a home or small office network. |
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| 2. Look for a local NDN router by DNS query with default suffix. |
| This allows network administrator to configure a NDN router for a large enterprise network. |
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| 3. Connect to the home NDN router according to user certificate. |
| This ensures connectivity from anywhere. |
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| Stage 1: multicast discovery |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
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| Request |
| +++++++ |
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| The end host sends an Interest over a multicast face. |
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| Interest Name is ``/localhop/ndn-autoconf/hub``. |
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| Response |
| ++++++++ |
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| A producer app on the HUB answer this Interest with a Data packet that contains a TLV-encoded `Uri` block. |
| The value of this block is the URI for the HUB, preferrably a UDP tunnel. |
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| Stage 2: DNS query with default suffix |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
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| Request |
| +++++++ |
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| The end host sends a DNS query that is equivalent to this command:: |
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| dig +search +short +cmd +tries=2 +ndots=10 _ndn._udp srv |
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| Response |
| ++++++++ |
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| The DNS server should answer with an SRV record that contains the hostname and UDP port number of the NDN router. |
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| Stage 3: find home router |
| ^^^^^^^^^^^^^^^^^^^^^^^^^ |
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| This stage assumes that user has configured default certificate using `<http://ndncert.named-data.net/>`_ as described in `Certification Architecture <http://redmine.named-data.net/attachments/download/23/CertificationArchitecture.pptx>`_. |
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| Request |
| +++++++ |
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| The end host loads the default user identity (eg. ``/ndn/edu/ucla/cs/afanasev``), and converts it to DNS format. |
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| 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:: |
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| _ndn._udp.afanasev.cs.ucla.edu.ndn._homehub._autoconf.named-data.net |
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| Response |
| ++++++++ |
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| The DNS server should answer with an SRV record that contains the hostname and UDP port number of the home NDN router of this user's site. |
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| Client procedure |
| ---------------- |
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| Stage 1 |
| ^^^^^^^ |
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| Send a multicast discovery Interest. |
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| If this Interest is answered, connect to the HUB and terminate auto-discovery. |
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| Stage 2 |
| ^^^^^^^ |
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| Send a DNS query with default suffix. |
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| If this query is answered, connect to the HUB and terminate auto-discovery. |
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| Stage 3 |
| ^^^^^^^ |
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| * Load default user identity, and convert it to DNS format; if either fails, the auto-discovery fails. |
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| * 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. |