draft-rosen-dns-sos-02

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draft-rosen-dns-sos-02

• Brian Rosen

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The basic idea

• 123.main.pittsburgh.allegheny.pa.us.sos.arpa
  contains a NAPTR, sospsap, of something like
  sipnewcom_at_psap.state.pa.us
• As specified, its a straight DDDS application
• All A(n) levels of PIDF-LO must be present (use
  .null if not used in a locale)
• A combination rule creates the street name and
  house number fields including prefixes and
  postfixes
• Regular DNS delegation rules for components

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NAPTRs in the heirarchy

• PSAP URI
• Other responder URIs
• Pointer to polygon list
• Pointer to XML list of next level down names
  (facilitates validation error processing) and
  polygon list creation
• Pointer to additional information available about
  this location

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Start up

• Delegate sos.arpa to e.g. ITU
• Delegate cc.sos.arpa to e.g. NENA or a govt
  agency
• This is sufficient for many countries where there
  is only one PSAP
• Delegate state/province.cc.sos.arpa to some
  state/province agency or just list them
• This is sufficient for many countries where there
  are a small number of PSAPs on regional
  boundaries
• Delegate county.state.cc.sos.arpa to the
  appropriate agencies
• This is sufficient for many areas where PSAPs
  match county boundaries
• Delegate city.county.state.cc.sos.arpa to the
  appropriate agency
• This is sufficient for many areas where some
  cities have their own PSAP
• Fill in street data from existing SAG, where SAG
  exists

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Some problems

• International names
• Use IDN
• Names can get long
• Use consistently applied abbreviations
• Isnt XML
• Yeah, but its simple enough
• Polygon search requires more work at resolver.
• Not ideal, but workable.

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Why do this?

• We know, with a lot of certainty, that it will
  work when disasters occur
• We know, with a lot of certainty, what the
  problems (deployment, scaling, startup, security)
  are
• This not to say that the answers are so obvious
• The delegation mechanism works for the realistic
  cases
• Simple things (one PSAP per country) is trivial
• Complex things (all of three cities, plus several
  streets, minus a few houses on one street) are
  possible