Network Working Group                                         D.L. Mills
Request for Comments: 996                         University of Delaware
                                                           February 1987

                           Statistics Server


   This RFC specifies a standard for the ARPA Internet community. Hosts
   and gateways on the DARPA Internet that choose to implement a remote
   statistics monitoring facility may use this protocol to send
   statistics data upon request to a monitoring center or debugging
   host.  Distribution of this memo is unlimited.


   Many host and gateway implementations include a facility which
   records traffic statistics, such as packet counters, error counters
   and significant event counters for debugging and performance
   evluation.  Simple data-access and formatting programs can be used to
   display these statistics along with the status of connections, etc.
   Several operating systems, including the various Unix systems and
   Fuzzball systems, already provide extensive facilities to capture and
   display these data for local users and/or operators.

   In many instances it is highly useful to observe statistics data on
   remote hosts and gateways from a monitoring center or debugging host.
   Indeed, several protocols have been implemented and used expressly
   for this purpose [1-6]. In many cases the data can be retrieved using
   conventional services such as remote login or even file transfer.
   However, use of these heavyweight mechanisms is awkward and intrusive
   if conducted on a regular, frequent basis and may involve substantial
   intrusion in the operating system if retrofitted to existing systems.

   The Statistics Server (STATSRV) protocol is intended as a lightweight
   mechanism similar in spirit to NETSTAT [7] and complementary to it.
   STATSRV is designed to capture statistics data with minimal intrusion
   on existing systems or networks. It is intended for use with existing
   hosts and gateways primarily for casual monitoring and debugging
   purposes. It is not intended as a full-function monitoring protocol
   [1,5,6] providing detailed, standardized reports suitable for machine
   analysis, for example, but could be useful in exploratory development
   leading to enduring systems of this type.

   The STATSRV model is based on the native host command language used
   for statistics monitoring and display. The client sends a null-
   terminated ASCII command to the server, which then responds with a
   null-terminated ASCII response suitable for a printer or CRT display.
   Although in principle STATSRV could be used over TCP, it is less
   intrusive and more efficient to use it over UDP. In the case of UDP,

D. L. Mills                                                     [Page 1]
RFC 996                                                    February 1987

   commands and responses must fit into a single 576-octet IP datagram.
   In both UDP and TCP the assigned port number is 133 (decimal).

   As is conventional in other lightweight services of this type
   (NETSTAT, FINGER, etc.), there is no provision for access control or
   authentication in STATSRV. If necessary, each command could include a
   password or other mechanism to discourage casual abuse.


   The Fuzzball system includes many local commands to display internal
   data structures, including one that produces the following billboard
   for each network device, in this case "dm0" on host "":

        Process type: 000027  options: 040000
        Subnet: DMV  status: 376  hello: 15  timeout: 2000
        Foreign address: []  max size: 576
        Input packets      3645    Output packets  3690
          bad format       0       ICMP msgs       0
          bad checksum     0       Input errors    0
          returned         0       Output errors   0
          dropped          2       No buffer       0
          HELLO msgs       2286    Preempted       0

   The same billboard is returned as a null-terminated ASCII string in a
   UDP datagram by sending the null-terminated ASCII command "dm0" in a
   UDP datagram to the host. Similar billboards can be produced for most
   processes in the system. Unix programs and shell scripts have been
   built which send commands like these to selected hosts on a periodic
   basis in order to construct a simple, ad-hoc monitoring facility.


   [1]  Flood Page, D.,"Gateway Monitoring Protocol", DARPA Network
        Working Group Report IEN-131, Bolt Beranek and Newman, February

   [2]  Flood Page, D., "The CMCC Terminal Process", DARPA Network
        Working Group Report IEN-132, Bolt Beranek and Newman, February

   [3]  Flood Page, D., "CMCC Performance Measurement Message Formats",
        DARPA Network Working Group Report IEN-157, Bolt Beranek and
        Newman, September 1980.

   [4]  Jones, R.G., " A Proposal for Simple Measurement Support for
        Users", DARPA Network Working Group Report IEN-161, University
        College London, November 1980.

D. L. Mills                                                     [Page 2]
RFC 996                                                    February 1987

   [5]  Littauer, B.M., A.J. Huang and R.M. Hinden," A Host Monitoring
        Protocol", DARPA Network Working Group Report IEN-197, Bolt
        Beranek and Newman, September 1981.

   [6]  Hinden, R.M.," A Host Monitoring Protocol", DARPA Network
        Working Group Report RFC-869, BBN Communications Corporation,
        December 1983.

   [7]  Reynolds, J.K., and J. Postel, "Assigned Numbers", DARPA Network
        Working Group Report RFC-990, USC Information Sciences
        Institute, November 1986.

D. L. Mills                                                     [Page 3]