rfc323.txt

RFC技术文档 从0000－05

Network Working Group                                          Vint Cerf
Request for Comments: 323                                       UCLA-NMC
NIC: 9630                                                 March 23, 1972


              Formation of Network Measurement Group (NMG)

   On March 17, 1972, at MIT project MAC, the following group met to
   discuss plans to perform measurement experiments on the ARPANET:

                    A. Bhushan     - MIT/DMCG

                    V. Cerf        - UCLA/NMC, Chairman, NMG

                    S. Crocker     - ARPA/IPT

                    J. Forgie      - LL/TX-2

                    R. Metcalfe    - MIT/HARV/DMCG

                    M. Padlipsky   - MIT/MULTICS

                    J. Postel      - UCLA/NMC

                    J. Winett      - LL/67

   The purpose of the meeting was to discuss existing and planned
   measurements of network and HOST behavior.

1.  Measurement Link #'s

   It was agreed (after a ridiculously long discussion) to allocate
   links 159-191 for network measurement only (see RFC #317).  It was
   further agreed that these links would be allocated in the following
   way:

         159-174  HOST DISCARD; co-operating HOSTS receiving messages on
                  these links will throw them away without generating an
                  error message.

         175-190  To be allocated as needed by V. Cerf - UCLA/NMC.

         191      To be used by IMPs to send measurement traffic
                  obtained from IMP statistics packages.







Cerf                                                            [Page 1]

RFC 323          Formation of Network Measurement Group       March 1972


   It should be apparent that HOSTs wishing to co-operate in the support
   of a HOST discard service should modify their NCP's to throw away all
   messages received on links 159-174 without sending an error back to
   the source HOST (no connection will be open on these links).

2.  Process Discard

   Although it was not mentioned at the meeting, C. Kline at UCLA has
   suggested a PROCESS DISCARD also with some well known socket number.
   The purpose of this discard routine would be to help us study
   Process-Process behavior of the network.

   It would be convenient if all co-operating HOSTs could write a
   Process Discard program which would simply wait for ICP on some
   standard socket number.  Until a complete survey is made of well-
   known socket numbers at each HOST, no socket number will be proposed
   (see RFC #322).

3.  NCP Statistics

   At the meeting it was apparent that several sites have already
   instrumented their NCP's out of curiosity.  In particular, Joel
   Winett, Lincoln Labs (360/67), has instrumented all connections
   originated by local TELNET users.  He gathers statistics per
   connection such as:

         a) Network connect time

         b) NCP CPU time

         c) Number of reads or writes on connection

         d) Time stamps on:

               first RFC, last RFC, first close, last close.

         e) Number of messages and bits transmitted

         f) Log of errors sent or received

   MULTICS gathers summary statistics on the number of regular (type 0)
   messages sent and received, and the number of irregular messages (not
   type 0) sent or received.








Cerf                                                            [Page 2]

RFC 323          Formation of Network Measurement Group       March 1972


   The NWG agreed to implement a minimal NCP instrumentation procedure
   which would gather by HOST for some standard 24 hour period (e.g.
   local midnight to local midnight) the following:

         a. Total bits sent to HOST

         b. Total bits received from HOST

         c. Total messages sent to HOST

         d. Total messages received from HOST and optionally

         e. Average Round Trip delay on send connections to HOST

   The information above should be collected only for standard open
   connections (i.e. those using standard NCP protocol) and not
   Measurement links or experimental NCP links, and in particular, not
   traffic on link 0).

   Another optional measurement would be to gather the distribution of
   message types over link 0 over all HOSTS (i.e. not broken down by
   HOST).  This will reveal the relative utilization of control messages
   (ALLOC should be very prevalent).

   The data collected for the last 24 hour sample period should be
   available from a process whose well-known (to be specified) socket
   number will support ICP and will produce a message in the following
   format:























Cerf                                                            [Page 3]

RFC 323          Formation of Network Measurement Group       March 1972


                   16         16
               +----------+------------+
word 0         |  Day #   |  Time      |
               +----------+------------+
                  |            |
 1 - 365 (6 on leap year)      |______
                                      |
                                Time in minutes at which sample was
                                started.  Ranges from 0 (midnight) to 1439.

                8      8
            +--------+------+-------+----------+
word 1      | Source | Byte |   N   |  Format  |
            |   Host | Size |       |          |
            +--------+------+-------+----------+
                |       |       |       |_____________
     ___________|       |       |                     |
    |                   |       |                     |
Network                 |       |        +-----+-----+--+--+--+--+
Host number             |       |        |     |     |C |R |B |M |
                        |       |        +-----+-----+--+--+--+--+
                        |       |                     |  |  |  |
                        |       |                     |  |  | message
                        |    number of HOST           |  |  | statistics
                        |    related entries          |  |  |
                        |    in message               |  |  |__byte
                        |                             |  |  statistics
                        |                             |  |
            number of bits per                        |  |__average
            byte in byte statistics                   |  round-trip
                                                      |  time
                                                      |
                                                      |__control
                                                      message
                                                      distribution
















Cerf                                                            [Page 4]

RFC 323          Formation of Network Measurement Group       March 1972


   The remaining words of the message depend on Format byte setting:

                  <-------32--------->
                +---------------------+
                |   Foreign HOST #    |      always present
              / +---------------------+
              | |  messages received  |      if FORMAT bit M set
              | +---------------------+
              | |    Bytes received   |      if FORMAT bit B set
   N of these | +---------------------+
   entries    | |     message sent    |      if FORMAT bit M set
              | +---------------------+
              | |      Bytes sent     |      if FORMAT bit B set
              | +---------------------+
              \ |   Average delay     |      if FORMAT bit R set
                +---------------------+
                                             This is average RFNM
                                             delay in milliseconds

             8         24
          +-------+---------------+
          |  type |     Count     |     if FORMAT bit C set these
          +-------+---------------+     are link 0 control message
          |       |               |     distributions for the