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

                                                         February 1987

                         Statistics Server

STATUS OF THIS MEMO

 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.

DISCUSSION

 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.

EXAMPLE

 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 "udel2.udel.edu":

      Process type: 000027  options: 040000
      Subnet: DMV  status: 376  hello: 15  timeout: 2000
      Foreign address: [192.5.39.87]  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.

REFERENCES

 [1]  Flood Page, D.,"Gateway Monitoring Protocol", DARPA Network
      Working Group Report IEN-131, Bolt Beranek and Newman, February
      1980.

 [2]  Flood Page, D., "The CMCC Terminal Process", DARPA Network
      Working Group Report IEN-132, Bolt Beranek and Newman, February
      1980.

 [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]