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(-> 4234^draft) [RFC2234]).

2.1.1. Request Payload Format

   request   = nth_digit

   nth_digit = 1*DIGIT  ; specifying the n-th digit following the
                        ; decimal point

2.1.2. Reply Payload Format

   reply  = nth_digit ":" DIGIT ; where DIGIT is the value of the n-th
                                ; digit following the decimal
                                ; point

2.2. Approximate Service

An OPTIONAL PIgen service is defined as a stateless UDP service. A server listens on UDP port 220007. When a datagram requesting a specific digit of the rational number 22/7 is received, an answering datagram is sent containing the value of the requested digit of 22/7 according to the format defined in sections 2.1.1. and 2.1.2.