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rfc:rfc460

Network Working Group Chuck S. Kline CSK Request for Comments: 460 UCLA NIC 14415 13 February 73

                             NCP Survey
 1 This RFC is the first in a series which will request information on
 implementation of host to host protocol.  We would appreciate a reply
 to this RFC from all sites within two weeks.  One convenient way to
 reply is to make a copy of this RFC at the NIC and insert the replies
 at the appropriate spots.  The results of this survey will be
 published.  Please send replies to nic ident CSK or to
 Charles Kline
 Boelter Hall 3804
 UCLA
 405 Hilgard Ave.
 Los Angeles, Cal. 90034
 2 This particular RFC will deal with implementations of Network
 Control Programs (NCPs).  Future RFCs will deal with .
 implementations of Telnet, RJE, etc.
 3 In order to ask questions about NCPs and get meaningful replies, I
 will here describe what I consider to be my concept of an NCP.
    3a An NCP is that part of the system which performs the tasks
    necessary for host to host protocol as specified by document NIC
    7104 (protocols notebook).
    3b NCPs contain the following parts (though not necessarily as
    separate pieces):
       3b1 Code which handles connection establishment including
       maintenance of the rendezvous table (table of open and pending
       connections).
       3b2 Code which handles transmission over open connections
       including buffer management and the sending of allocate and
       giveback commands.
       3b3 Code which handles the actual movement of messages in and
       out of the Imp (sometimes called the Imp handler and sometimes
       in a separate cpu).
       3b4 Other code including measurements, initialization, etc.

Kline [Page 1] RFC 460 NCP Survey February 1973

 4. Please answer the following questions.  It is probably appropriate
 to give this survey to the coder of the NCP or other knowledgeable
 person.  Write na (not applicable) where it is appropriate.  Circle
 the number of the appropriate choice when a choice is required.
 Thank you.
 5 General Information
    5a Host Name: ----
    5b Site Number: ----
    5c Your name ----
    5d Main cpu is a ---- (360/75, PDP-10, B6700, etc.)
    5e Operating system in main cpu is ---- (tenex, os/360, etc.)
    5f Is documentation available on your NCP?
       5f1 user level (how to use NCP)
       5f2 system level (implementation)
       5f3 Is the documentation available at the NIC?
 6 Imp interface
    6a built:
       6a1 in house
       6a2 contracted to ----
    6b full or half duplex?
    6c maximum bandwidth is ---- baud in each direction
 7 Coding of NCP
    7a ncp was written:
       7a1 in house
          7a1a written in ---- man-months
          7a1b Name of person who wrote NCP ----

Kline [Page 2] RFC 460 NCP Survey February 1973

          7a1c debugged in ---- man-weeks
          7a1d machine hours used in development and debugging of NCP
          ----
       7a2 contracted to ----
          7a2a contractor took ---- man-months
       7a3 supplied another site without modification by this site
       (specify site where NCP obtained from ------).
       7a4 supplied from another site but modified by this site for
       different system or for other reasons (specify site where NCP
       obtained from ------)
          7a4a modifications took ---- man-weeks
    7b NCP is maintained:
       7b1 in house (person's name ----)
       7b2 by another site (specify site ----)
    7c Size of NCP code:
       7c1 Total size of all NCP code (not tables or buffers) as
       described above
          7c1a ---- words of ---- bits per word
       7c2 size of code which initializes NCP (on system up or after
       NCP or NET crash)
          7c2a ---- words of ---- bits per word
       7c3 size of code which handles opening and closing of
       connections
          7c3a ---- words of ---- bits per word
       7c4 size of code which moves data from user process to Imp
       handler or from Imp handler to user process
          7c4a ---- words of ---- bits per word

Kline [Page 3] RFC 460 NCP Survey February 1973

       7c5 size of Imp handler code
          7c5a ---- words of ---- bits per word
       7c6 size of other code (explain what it is)
          7c6a ---- words of ---- bits per word
    7d Size of NCP tables:
       7d1 size of tables indexed by open connection (i.e. tables for
       control of open connections)
          7d1a ---- entries or ---- words per entry of ---- bits per
          word
       7d2 size of tables indexed by link (i.e. tables for link
       management and for quick association of an input message with a
       process)
          7d2a ---- entries of ---- words per entry of ---- bits per
          word
       7d3 size of other tables (explain)
          7d3a ---- entries of ---- words per entry of ---- bits per
          word
 8 Host-Imp communications
    8a Imp handling is performed in
       8a1 main cpu
       8a2 additional processor (specify machine ----)
    8b Imp handling is performed at:
       8b1 interrupt level by resident code
       8b2 scheduled process with resident code
       8b3 scheduled process with swappable code
    8c Number and size of buffers for the Imp handler (on input,
    number of buffers for messages before cpu will stop taking bits
    from imp.  On output, number of buffers which may be queued before
    user processes will be blocked waiting for a free buffer)

Kline [Page 4] RFC 460 NCP Survey February 1973

       8c1 ---- output buffers for sending to net of ---- words of
       ---- bits per word
       8c2 ---- input buffers for receiving from net of ---- words of
       ---- bits per word
 9 NCP-Imp handler communications
    9a NCP communicates with Imp handler by
       9a1 putting message on queue for handler and waking
       (unblocking) handler (i.e. shared memory approach)
       9a2 some other mechanism (explain)
 10 NCP-User communication
    10a Mechanism:
       10a1 special mechanism for network (i.e. different than files)
       using:
          10a1a shared resident memory
          10a1b shared non-resident (swappable memory or file)
          10a1c other (explain)
       10a2 similar to file io but network assigned rather than file
       (i.e. transparent to user process coding)
    10b Bytes sizes allowed (circle all)
       10b1 1 bit
       10b2 7 bit
       10b3 8 bit
       10b4 9 bit
       10b5 16 bit
       10b6 18 bit
       10b7 24 bit
       10b8 32 bit

Kline [Page 5] RFC 460 NCP Survey February 1973

       10b9 36 bit
       10b10 other (explain)
 11 Buffer space allocations
    11a initial allocation when connection (receive) is opened
       11a1 ---- messages and ---- bits
    11b factors which will change this allocation
       11b1 up
       11b2 down
    11c conditions which would cause a giveback command to be sent
 12 Protocol facilities
    12a Errors
       12a1 Do you send error commands when you detect protocol
       errors?
       12a2 Do you log it (or take some other action) when you recieve
       error commands?
    12b Queuing
       12b1 do you allow queuing of connections (i.e. when an rts or
       str is received for which no request is pending, do you refuse
       it (send back a cls) or queue it? also do you queue when two or
       more requests match the same socket?)
          12b1a yes always
          12b1b no always
          12b1c yes for listens
          12b1d other (explain)
       12c Are there hooks (code) in the NCP for:
          12c1 NCP measurement
          12c2 Network measurement

Kline [Page 6] RFC 460 NCP Survey February 1973

          12c3 MSP and other protocol experiments
          12c4 Do any of these hooks allow a user process to send a
          message with a given leader or look at all messages which
          arrive with a given leader?
 13 Time outs
    13a How long will the NCP hold a request for connection (INIT or
    LISTEN) from a user process before timing out if not matched by an
    RTS or STR from the net ----
    13b How long will the NCP hold an STR or RTS recieved from the net
    before timing out and sending a CLS ----
    13c How long will the NCP wait after sending a reset or echo
    command before declaring the host dead (assuming you got a RFNM at
    least) ----
    13d Any other timeouts? (explain)
 14 Have you made any measurements on the effect of network use on
 your system?
    14a effect of local users using telnet to go out to net
    14b effect of foreign users using your system via net
    14c bandwidth you have been able to achieve
 15 Are any changes planned or in progress in the design or coding of
 your NCP? (explain)
 16 Other Comments
    16a Please feel free to add other comments on your NCP which you
    feel would be of interest to the network community.
     [ This RFC was put into machine readable form for entry ]
       [ into the online RFC archives by Grant Bowman 11/97 ]

Kline [Page 7]

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