RFC 1861 (rfc1861) - Page 3 of 26

Simple Network Paging Protocol - Version 3 -Two-Way Enhanced

RFC 1861                   SNPP - Version 3                October 1995


3. Why not just use Email and SMTP for paging?

   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.

   Another advantage of using a separate protocol for paging delivery is
   that it gives the sender absolute flexibility over what is sent to
   the pager.  For instance, in the paging arena, where messages are
   sent to alphanumeric pagers, it is less desirable to send the
   recipient general header lines from a standard SMTP message.  Much of
   the information is useless, possibly redundant, and a waste of
   precious RF bandwidth.

   Therefore, when implementing an SMTP gateway, the service provider
   should elect to parse out needed information (such as the sender, and
   possibly subject) such to maximize the utility of the transmission.
   Parsing generally means less control over content and format by the
   message originator.  SNPP provides a clean, effective way to send a
   message, as written, to the recipient's pager.

   The other consideration is the relative simplicity of the SNPP
   protocol for manual telnet sessions versus someone trying to manually
   hack a mail message into a gateway.





Gwinn                        Informational