RFC 1645 (rfc1645) - Page 2 of 18

Simple Network Paging Protocol - Version 2

RFC 1645                    SNPP - Version 2                   July 1994


   some paging terminal, somewhere.  In most cases, this delivery is
   made using TAP (Telocator Alphanumeric input Protocol, also known as
   IXO).  This protocol can be a somewhat convoluted, and complicated
   protocol using older style ASCII control characters and a non-
   standard checksumming routine to assist in validating the data.

   Even though TAP is widely used throughout the industry, there are
   plans on the table to move to a more flexible "standard" protocol
   referred to as TME (Telocator Message Entry Protocol).  The level two
   enhancements to SNPP (as described below) are intended for use with
   this forthcoming standard.

   However, acknowledging the complexity and flexibility of the current
   protocols (or the lack thereof), the final user function is quite
   simple: to deliver a page from point-of-origin to someone's beeper.
   That is the simple, real-time function that the base protocol
   attempts to address.  Validation of the paging information is left
   completely up to the paging terminal, making an SNPP gateway a direct
   "shim" between a paging terminal and the Internet.

3. Why not just use Email and SMTP?

   Email, while quite reliable, is not always timely.  A good example of
   this is deferred messaging when a gateway is down. Suppose Mary Ghoti
   () sends a message to Zaphod Beeblebrox's beeper
   (). Hugecompany's gateway to the
   Internet is down causing Mary's message to be deferred.  Mary,
   however, is not notified of this delay because her message has not
   actually failed to reach its destination.  Three hours later, the
   link is restored, and (as soon as sendmail wakes up) the message is
   sent.  Obviously, if Mary's page concerned a meeting that was
   supposed to happen 2 hours ago, there will be some minor
   administrative details to work out between Mary and Zaphod!

   On the other hand, if Mary had used her SNPP client (or simply
   telnetted to the SNPP gateway), she would have immediately discovered
   the network problem.  She would have decided to invoke plan "B" and
   call Zaphod's pager on the telephone, ringing him that way.

   The obvious difference here is not page delivery, but the immediate
   notification of a problem that affects your message. Standard email
   and SMTP, while quite reliable in most cases, cannot be positively
   guaranteed between all nodes at all times, making it less desirable
   for emergency or urgent paging.  This inability to guarantee delivery
   could, whether rightly or wrongly, place the service provider in an
   uncomfortable position with a client who has just received his or her
   emergency page, six hours too late.




Gwinn