RFC 3091 (rfc3091) - Page 2 of 6

Pi Digit Generation Protocol

RFC 3091              Pi Digit Generation Protocol          1 April 2001


   starting with the most significant digit following the decimal point.
   Any incoming data MUST be discarded.  This continues until the client
   closes the connection.

   The data flow over the connection is limited by the normal TCP flow
   control mechanisms, so there is no concern about the server sending
   data faster than the client can process it.

   Servers MAY use any appropriate method of Pi digit generation to
   provide this service, including (but not limited to) table lookup
   [DIGITS], numerical calculation [FIBPI,PIFFT] and statistical
   sampling [MCM].  However, the method chosen SHOULD provide a precise
   value for the digits of Pi generated.

   Implementors of PIgen MUST provide this service to be conditionally
   compliant with this RFC.

1.1.   Approximate Service

   An OPTIONAL PIgen service is defined as a stateless TCP service.  A
   server listens on TCP port 220007.  Once a connection is established
   the server sends a stream of data, one digit of the rational number
   22/7 at a time, starting with the most significant digit following
   the decimal point.  Any incoming data MUST be discarded.  This
   continues until the client closes the connection.

2.     UDP Based Digit Generator Service

   An OPTIONAL PIgen service is defined as a stateless UDP service.  A
   server listens on UDP port 314159.  When a datagram requesting a
   specific digit of Pi is received, an answering datagram is sent
   containing the value of the requested digit of Pi according to the
   format defined in sections 2.1.1. and 2.1.2.

   The requested digit value MAY be determined by any appropriate method
   of Pi digit generation.  RECOMMENDED methods include table lookup
   [DIGITS], or numerical calculation [BBPPA].

2.1.   Packet Format

   The datagram-based components of the PIgen protocol suite all share
   the following UDP data payload formats (defined in the ABNF of RFC
   2234 [RFC 2234]).








Kennedy                      Informational