5. Operational constraints

   This section lays out some of the operational issues with deployment
   of HTCPCP ubiquitously.

5.1 Timing Considerations

   A robust quality of service is required between the coffee pot user
   and the coffee pot service.  Coffee pots SHOULD use the Network Time
   Protocol [NTP] to synchronize their clocks to a globally accurate
   time standard.

   Telerobotics has been an expensive technology. However, with the
   advent of the Cambridge Coffee Pot [CAM], the use of the web (rather
   than SNMP) for remote system monitoring and management has been
   proven.  Additional coffee pot maintenance tasks might be
   accomplished by remote robotics.

   Web data is normally static. Therefore to save data transmission and
   time, Web browser programs store each Web page retrieved by a user on
   the user's computer. Thus, if the user wants to return to that page,
   it is now stored locally and does not need to be requested again from
   the server. An image used for robot control or for monitoring a
   changing scene is dynamic. A fresh version needs to be retrieved from
   the server each time it is accessed.

5.2 Crossing firewalls

   In most organizations HTTP traffic crosses firewalls fairly easily.
   Modern coffee pots do not use fire. However, a "firewall" is useful
   for protection of any source from any manner of heat, and not just
   fire. Every home computer network SHOULD be protected by a firewall
   from sources of heat. However, remote control of coffee pots is




 
RFC 2324                       HTCPCP/1.0                   1 April 1998


   important from outside the home. Thus, it is important that HTCPCP
   cross firewalls easily.

   By basing HTCPCP on HTTP and using port 80, it will get all of HTTP's
   firewall-crossing virtues. Of course, the home firewalls will require
   reconfiguration or new versions in order to accommodate HTCPCP-
   specific methods, headers and trailers, but such upgrades will be
   easily accommodated. Most home network system administrators drink
   coffee, and are willing to accommodate the needs of tunnelling
   HTCPCP.

6. System management considerations

   Coffee pot monitoring using HTTP protocols has been an early
   application of the web.  In the earliest instance, coffee pot
   monitoring was an early (and appropriate) use of ATM networks [CAM].

   The traditional technique [CAM] was to attach a frame-grabber to a
   video camera, and feed the images to a web server. This was an
   appropriate application of ATM networks. In this coffee pot
   installation, the Trojan Room of Cambridge University laboratories
   was used to give a web interface to monitor a common coffee pot.  of
   us involved in related research and, being poor, impoverished
   academics, we only had one coffee filter machine between us, which
   lived in the corridor just outside the Trojan Room. However, being
   highly dedicated and hard-working academics, we got through a lot of
   coffee, and when a fresh pot was brewed, it often didn't last long.

   This service was created as the first application to use a new RPC
   mechanism designed in the Cambridge Computer Laboratory - MSRPC2. It
   runs over MSNL (Multi-Service Network Layer) - a network layer
   protocol designed for ATM networks.

   Coffee pots on the Internet may be managed using the Coffee Pot MIB
   [CPMIB].

7. Security Considerations

   Anyone who gets in between me and my morning coffee should be
   insecure.

   Unmoderated access to unprotected coffee pots from Internet users
   might lead to several kinds of "denial of coffee service" attacks.
   The improper use of filtration devices might admit trojan grounds.
   Filtration is not a good virus protection method.







 
RFC 2324                       HTCPCP/1.0                   1 April 1998


   Putting coffee grounds into Internet plumbing may result in clogged
   plumbing, which would entail the services of an Internet Plumber
   [PLUMB], who would, in turn, require an Internet Plumber's Helper.