*COMDECK IMSNBT 
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*1DC NBT - NETWORK BUFFER TABLE 
* 
*     NBT IS USED BY NIP AND PIP TO TRANSFER ALL NETWORK TRAFFIC EXCEPT 
*     PRU DATA AND TO COMMUNICATE WITH EACH OTHER VIA WORKLIST. 
*     TABLE IS ALLOCATED AT INITIALIZATION TIME AND MUST BE THE FIRST 
*     TABLE AFTER THE END OF NIP-S PROGRAM MEMORY SPACE.  IT IS NEVER 
*     MOVED NOR CHANGED IN SIZE.  THE TABLE CONSISTS OF 1 HEADER WORD 
*     FOLLOWED BY UP TO 16 24 WORD ENTRIES.  THE NUMBER OF ENTRIES IN 
*     THE TABLE DEPENDS ON THE NUMBER OF NP/ND EST ENTRIES THAT PIP 
*     FINDS IN THE EST AT INITIALIZATION TIME UP TO A MAXIMUM OF 16.
*     EACH ENTRY WILL BE USED TO DRIVE ONE FRONT END NPU/MDI.  THUS 
*     NIP CAN AT ANY TIME TALK TO A MAXIMUM OF 16 NPU/MDI-S EVEN
*     THOUGH THERE MAY BE MORE CONFIGURED.  WHEN AN NP/ND EST ENTRY IS
*     TURNED OFF, NIP WILL RELEASE THE CORRESPONDING ENTRY ASSOCIATED 
*     WITH THAT FRONT END.  WHEN AN NP/ND EST ENTRY IS TURNED ON, NIP 
*     SET UP AN UNUSED ENTRY.  EACH ENTRY CONSISTS OF SIX SETS OF FOUR- 
*     WORD PSEUDO FETS, THE FIRST TWO FOR INBOUND DATA AND THE NEXT 
*     THREE FOR OUTBOUND DATA.  THE LAST PSEUDO FET IS USED FOR 
*     MDI INLINE DIAGNOSTICS TESTING. 
* 
*                               1  1 1    2  22 3  3  3  3  4    4    5 
*                012345 678 9   2  5 8    4  78 0  3  6  9  2    8    9 
*               I------I-------I--I-I----I--I-II--I--I--I-------I----I-I
*     HEADER    I      I                 I     I     I               I I
*     WORD      I  ID  I       BS        I NAE I NFE I///////////////ICI
*               I------I-------I--I------I----I------I---------------I-I
*     FET(0)    II SBCBI       I  I      I    I      I     I           I
*     INBOUND   IU/AABRI  CH   IEQI EST  I       TA        I    FIRST  I
*               IF MFFFI       I  I      I    I      I     I           I
*               I------I-------I--I------I----I------I-----I-----------I
*               I//////////////////////////////////////////I    IN     I
*               I------I---I---I---------I-----------------I-----------I
*               I   REGW   I///I   ET    IINDXI  HN  I PIP I    OUT    I
*               I------I---I---I---------I-----------------I-----------I
*               I KNDX I      PCRB       I       PCRF      I    LIMIT  I
*               I--I---I-----------------I-----------------I-----------I
*     FET(1)    I  IBCBI                                   I           I
*     INBOUND   I//IABRI////////////I TN I       TA        I    FIRST  I
*               I  IFFFI                                   I           I
*               I--I---I-----------------------------------I-----------I
*               I                    0                     I    IN     I
*               I------------------------I-----------------I-----------I
*               I    RJCNT     I////I  CSIZE   I   COFF    I    OUT    I
*               I--------------I---I-----I--I-----I--I--I--I-----------I
*               I              I   I     I  I     I DI NI HI           I
*               I          RTIME         I//I CII I RI RI RI    LIMIT  I
*               I              I   I     I  I     I LI LI LI           I
*               I--------------I---I-----I--I-----I--I--I--I-----------I
*     FET(2)    I        NMQ        I//////////////////////I    FIRST  I
*     OUTBOUND  I-------------------I----------------I-----I-----------I
*               I                 IVTLS              I/////I    IN     I
*               I------------------------------------I-----I-----------I
*               I//////////////////////////////////////////I    OUT    I
*               I------------------------------------I-----I-----------I
*               I                 IVTWC              I      IVTCC      I
*               I-------------------I----------------I-----I-----------I
*     FET(3)    I        NMQ        I//////////////////////I    FIRST  I
*     OUTBOUND  I-------------------I----------------I-----I-----------I
*               I                 PRULS              I/////I    IN     I
*               I------------------------------------I-----I-----------I
*               I//////////////////////////////////////////I    OUT    I
*               I------------------------------------I-----I-----------I
*               I                 PRUSC              I      PRUCC      I
*               I-------------------I----------------I-----I-----------I
*     FET(4)    I        NMQ        I /////////////////////I    FIRST  I
*     OUTBOUND  I-------------------I----------------------I-----------I
*               I//////////////////////////////////////////I    IN     I
*               I------------------------------------------I-----------I
*               I//////////////////////////////////////////I    OUT    I
*               I-------I------I---------I-----------I-----I-----------I
*               IAIMBOLDI      I         I           I                 I
*               IFFFFFFFI//////I  NIREJ  I    NPREJ  I/////////////////I
*               I-I-I---I------I---------I-----------I-----I-----------I
*     FET(5)    IAI            I         I                 I           I
*     MCI       ICI////////////I  PIPTF  I/////////////////I    FIRST  I
*     INLINE    ITI            I         I                 I           I
*     DIAGS     I-I------------I---------I-----------------I-----------I
*     FET       IRRI                                       I           I
*               IEEI///////////////////////////////////////I    IN     I
*               IQLI                                       I           I
*               I--I---------------------------------------I-----------I
*               I//////////////////////////////////////////I    OUT    I
*               I--------------I---------I-----------I-----I-----------I
*               I              I         I           I     I           I
*               I//////////////I  PIREJ  I   PPREJ   I/////I    LIMIT  I
*               I              I         I           I     I           I
*               I--------------I----I----I-----------I-----I-----------I
*                0123456789     1    1                3     4    4    5 
*                               2    8                6     2    8    9 
* 
*     HEADER HAS ITEMS: 
*       NBTID   = NETWORK BUFFER TABLE ID = 15
*       NBTBS   = NBT BLOCK SIZE
*       NBTNAE  = NUMBER OF ACTIVE NBT ENTRIES
*       NBTNFE  = NUMBER OF FREE NBT ENTRIES
*       NBTC    = PIP TYPE 1 CALL COMPLETION FLAG 
* 
*     EACH NBT ENTRY HAS GLOBAL ITEMS 
*       - IN PSEUDO FET (0) - 
*       NBTIUF  = IN USE FLAG, SET BY NIP WHEN NBT ENTRY IS SET UP
*                 AND IS CLEARED WHEN IT IS RELEASED. 
*       NBTSAM  = SAM FLAG, SET IF FRONT-END IS EQUIPPED WITH SAM.
*       NBTCH   = CHANNEL NUMBER OF COUPLER 
*       NBTEQ   = EQUIPMENT NUMBER OF COUPLER 
*       NBTEST  = EST ORDINAL OF NP/NQ
*       NBTINDX = NBT ENTRY INDEX (1-8) 
*       NBTHN   = HOST NODE NUMBER ASSIGNED TO COUPLER
*       NBTPIP  = PIP NUMBER FROM EST 
*       NBTREGW = COUNTER OF (PRU) LLCBS WATING OFF 
*       NBTET   = EQUIPMENT MNEUMONIC 
*       NBTKNDX = INDEX TO STATUS DISPLAY DATA BUFFER 
*       NBTPCRB = PRU CONNECTION RING BACKWORD POINTER
*       NBTPCRF = PRU CONNECTION RING FORWARD POINTER 
*       - IN PSEUDO FET (1) - 
*       NBTCSIZE = CURRENT SIZE OF ALLOCATED INBOUND BUFFERS
*       NBTCOFF  = CURRENT OFFSET FOR THRESHOLD ADDRESS 
*       NBTRTIME = TIMEOUT FOR NO PIP REJECTS OF IVT DATA 
*       NBTRJCNT = CURRENT CNT OF NO OF PIP IVT REJECTS 
*       NBTTN    = CDCNET FRONT END TERMINAL NODE NUMBER
*       NBTCII  = CURRENT INBOUND BUFFER INDEX (0-1) TO KEEP TRACK
*                 OF BUFFER NIP IS CURRENTLY PROCESSING.
*       NBTDRL  = DESTINATION HOST REGULATION LEVEL 
*       NBTNRL  = NPU REGULATION LEVEL
*       NBTHRL  = HOST REGULATION LEVEL 
*       - IN PSEUDO FET (2) - 
*       NBTIVTLS = LAST IVT DATA CHARACTER COUNT
*       NBTIVTST = IVT STATISTICS 
*       NBTIVTWD = IBT DATA WORD COUND
*       NBTIVTCC = IVT DATA CHARACTER COUNT 
*       - IN PSEUDO FET (3) - 
*       NBTPRULS = LAST IVT DATA CHARACTER COUNT
*       NBTPRUST = IVT STATISTICS 
*       NBTPRUSC = IBT DATA WORD COUND
*       NBTPRUCC = IVT DATA CHARACTER COUNT 
*       - IN PSEUDO FET (4) - 
*       NBTAF   = NPU ACTIVE FLAG, SET UNLESS NPU IS STOPPED. 
*       NBTIF   = INITIALIZATION FLAG, SET WHEN INITIALIZATION ACTION 
*                 IS PENDING. 
*       NBTMF   = MAINTENANCE FLAG, SET WHILE NPU IS IN INITIALIZATION
*                 PROCESSING. 
*       NBTBF   = BOOTSTRAP LOADED FLAG, FOR NO SAM NPU, SET WHEN NPU 
*                 IS LOADED AND CLEARED WHEN NPU IS INITIALIZED.
*       NBTOF   = OFF NPU FLAG, SET BY PIP WHEN NPU IS TURNED OFF.
*       NBTLF   = LLK FLAG, SET BY PIP WHILE IT IS WAITING FOR
*                 LLK/REGL/0 COMPLETE, CLEARED BY NIP.
*       NBTDF   = DOWN FLAG, SET WHEN LOADING IS STARTED, CLEARED WHEN
*                 NPU IS STARTED OR INITIALIZED.
*       NBTNIREJ = COUNTER FOR NPU IVT DATA REJECTS 
*       NBTNPREJ = COUNTER OF NPU PRU DATA REJECTS
*       - IN PSEUDO FET (5) - 
*       NBTACT   = ACTIVE INLINE DIAGNOSTICS BUFFER FLAG
*       NBTREQ   = INLINE DIAGNOSTICS BUFFER REQUESTED  FLAG
*       NBTREL   = RELEASE INLINE DIAGNOSTICS BUFFER FLAG 
*       NBTPIPTF = PIP TRACE BUFFER INDICATOR 
*       NBTPIREJ = COUNTER OF PIP IVT DATA REJECTS
*       NBTPPREJ = COUNTER OF PIP PRU DATA REJECTS
* 
*     EACH INBOUND FET HAS THE FOLLOWING FIELDS 
*       NBTBFS = INBOUND BUFFER EXISTS FLAG 
*       NBTBAF = BUFFER AVAILABBLE FLAG 
*       NBTCBF = CURRENT ACTIVE BUFFER FLAG 
*       NBTBRF = BUFFER RELEASE FLAG
*       NBTTA  = THRESHOLD ADDR FOR ALLOCATING NEXT BUFFER
* 
*     EACH OUTBOUND FET HAS THE FOLLOWING FIELDS
*       NBTNMQ = NO OF MESSAGES QUEUED IN CHAIN 
* 
*     NIP INITIALLY ALLOCATES ONE INBOUND BUFFER (SETS NBTBAF) AND
*     PIP USES IT (SETS NBTCBF) AS LONG AS IT CAN USE IT.  NIP
*     ALLOCATES ANOTHER INBOUND BUFFER WHEN IT SEES THAT THE OTHER
*     BUFFER IS MORE THAN HALF USED.
*     WHEN PIP FINDS NO ROOM FOR NEXT INBOUND MESSAGE, IT SWITCHES
*     THE BUFFERS (SETS NBTBRF) IF AVAILABLE OR WAITS FOR IT. 
* 
*       NBTFIRST = FWA OF CURRENT PIP INBOUND BUFFER
*       NBTIN    = FWA OF UNUSED PORTION OF PIP INBOUND BUFFER
*       NBTOUT   = FWA OF UPLINE NETWORK BLOCK PLACED IN INBOUND
*                  BUFFER BY PIP
*       NBTLIMIT = LWA+1 OF CURRENT PIP INBOUND BUFFER
*       NBTBAF = BUFFER AVAILABLE FLAG SET BY NIP WHEN A BUFFER IS
*                ASSIGNED.
*       NBTCBF = CURRENT BUFFER FLAG SET BY PIP WHEN PIP HAS ACCESS 
*                TO IT. 
*       NBTBRF = BUFFER RELEASE FLAG SET BY PIP WHEN PIP IS NO LINGER 
*                ACESSING IT. 
* 
*     THREE OUTBOUND PSEUDO FET-S ARE FOR EACH OF THE 3 PRIORITIES. 
*     ALL DOWNLINE MESSAGES ARE QUEUED IN CHAIN.
* 
*       NBTFIRST = ADDRESS OF FIRST DOWNLINE MESSAGE IN THE CHAIN 
*       NBTIN    = ADDRESS OF LAST DOWNLINE MESSAGE IN THE CHAIN
*       NBTOUT   = ADDRESS OF LAST DOWNLINE MESSAGE PIP PICKED UP 
*       NBTNMQ = NUMBER OF MESSAGES QUEUED IN CHAIN 
* 
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