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PDP-10 Archives
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BB-H348C-RM_1982
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swskit-v21/documentation/decnet-datascope.chart
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DDCMP DATA MESSAGE
___________________________________________________________________
|| 81 | | | | 01 | blkck1 | data | blkck2 ||
++----+----+----+----+----+----+----+----+-------------+----+----++
1 2 3 4 5 6 7 8 9 ---> 9+count
1 SOH Data message identifier (201 octal, 81 hex)
2,3 COUNT Byte count field, size of data field, 14 bits
Low order bits in 2, high order bits in 3
FLAGS Link flags, 2 bits
Bit 0 = Quick sync flag (usually 1)
Bit 1 = Select flag (0 for DECnet20)
_____________________________________________________
|| low order count || S| Q| high order count||
-++--+--+--+--+--+--+--+--++--+--+--+--+--+--+--+--++-
2 3 4
4 RESP Response number, ACK number for LAST correctly
received DDCMP message (piggybacked ACK).
5 NUM Transmit number, number of this DDCMP message
6 ADDR Station address for multipoint (01 for DECnet20)
7,8 BLKCK1 Block check for numbered message header (bytes 1-6)
9 DATA Numbered message data field, length = COUNT
Data is totally transparent to protocol.
9+count BLKCK2 Block check for data field (bytes 9 to 9+COUNT-1)
DDCMP CONTROL MESSAGES
___________________________________________
|| 05 | | | | | 01 | blkck3 ||
++----+----+----+----+----+----+----+----++
1 2 3 4 5 6 7 8
1 ENQ Control message identifier = 5
2 TYPE Control message type
3 FLAGS Link flags, (S=0,Q=1)
SUBTYPE Type modifier, 6 bits
_____________________________
|| 0| 1| Subtype ||
-++--+--+--+--+--+--+--+--++-
4 RCVR Control message receiver field
5 SNDR Control message sender field
6 ADDR Station address for multipoint (01 for DECnet20)
7,8 BLKCK3 Block check for control message (bytes 1-6)
___________________________________________
ACK || 05 | 01 | 40 | | 00 | 01 | blkck3 ||
++----+----+----+----+----+----+----+----++
1 2 3 4 5 6 7 8
2 ACKTYPE ACK message = 1 _____________________
3 FLAGS (S=0,Q=1) ||0|1|0 0 0 0 0 0||
ACKSUB ACK subtype = 0 -++-+-+-+-+-+-+-+-++-
4 RESP Response number (piggybacked ACK for DDCMP).
___________________________________________
NAK || 05 | 02 | | | 00 | 01 | blkck3 ||
++----+----+----+----+----+----+----+----++
1 2 3 4 5 6 7 8
2 NAKTYPE ACK message = 2 _____________________
3 FLAGS (S=0,Q=1) ||0|1| NAK reason||
REASON NAK error reason -++-+-+-+-+-+-+-+-++-
1 = header block check error (BLKCK1 or BLKCK3)
2 = data field block check error (BLKCK2)
3 = REP response
8 = buffer temporarily unavailable
9 = receive overrun
16 = message too long (10 hex)
17 = message header format error (11 hex)
4 RESP Response number (piggybacked ACK for DDCMP).
___________________________________________
REP || 05 | 03 | 40 | 00 | | 01 | blkck3 ||
++----+----+----+----+----+----+----+----++
1 2 3 4 5 6 7 8
2 REPTYPE REP message = 3 _____________________
3,4 FLAGS (S=0,Q=1) ||0|1|0 0 0 0 0 0||
REPSUB ACK subtype = 0 -++-+-+-+-+-+-+-+-++-
5 NUM Last sequential numbered DDCMP data message.
___________________________________________
STRT || 05 | 06 | C0 | 00 | 00 | 01 | blkck3 ||
++----+----+----+----+----+----+----+----++
1 2 3 4 5 6 7 8
2 STRTYPE STRT message = 6 _____________________
3 FLAGS (S=1,Q=1) ||1|1|0 0 0 0 0 0||
STRTSUB STRT subtype = 0 -++-+-+-+-+-+-+-+-++-
___________________________________________
STACK || 05 | 07 | C0 | 00 | 00 | 01 | blkck3 ||
++----+----+----+----+----+----+----+----++
1 2 3 4 5 6 7 8
2 STACKTYPE STACK message = 7 _____________________
3 FLAGS (S=1,Q=1) ||1|1|0 0 0 0 0 0||
STACKSUB STACK subtype = 0 -++-+-+-+-+-+-+-+-++-
NSP MESSAGE
________________________________
Format || RTHDR*|| MSGFLG || MSGDATA ||
++-------++--------++---------++
* Phase II DECnet may omit the RTHDR from some NSP messages.
Usually, control messages have RTHDR's, data messages do not.
______________________________________________
RTHDR || 46 | n | | m | ||
++------+-----+---------+-----+---------++----
1 2 3 4+n 5+n 6+n+m
____________________
1 RTFLG Routing flags, ||0 1 0 0|MPRI|1 0||
MPRI = 1 for tranmission ++-+-+-+-+--+-+-+-++
2 DSTL Length of destination nodename ( 0<n<=6 )
3 DSTNODE Destination node name, alphanumeric (length DSTL)
4+n SRCL Length of source nodename ( 0<m<=6 )
5+n SRCNODE Source node name, alphanumeric (length SRCL)
___________________________
MSGFLG || 0| subtype| type| 0 0||
++--+--+--+--+--+--+--+--++
Hex Octal Sub Ty Message Type
00 000 0 000 00 00 Data segment
20 040 0 010 00 00 Data segment - BOM
40 100 0 100 00 00 Data segment - EOM
60 140 0 110 00 00 Data segment - BOM/EOM
10 020 0 000 10 00 Link services message
30 060 0 011 00 00 Interrupt message
04 010 0 000 01 00 ACK - Data segment
14 024 0 001 01 00 ACK - Interrupt/LS
24 044 0 010 01 00 ACK - Control
08 010 0 000 10 00 Control - NOP
18 030 0 001 10 00 CI - Connect Initiate
28 050 0 010 10 00 CC - Connect Confirm
38 070 0 011 10 00 DI - Disconnect Initiate
48 110 0 100 10 00 DC - Disconnect Confirm
58 130 0 101 10 00 Startup (1=Init, 2=Verify)
NSP DATA MESSAGE (no RTHDR)
___________________________________________________________
|| | | | * | | data ||
++----+----+----+----+----+----+----+----+----+----------++
1 2 3 4 5 6 7 8 9
1 MSGFLG 00, 20, 40, 60 (See explanation on previous page)
2,3 DSTADDR Logical link destination address for message
4,5 SRCADDR Logical link source address for message
6,7 ACKNUM* Number of last successful NSP message received.
* Optional field, present if bit 15 = 1.
QUAL(3b) 0=ACK, 1=NAK, 2-7=reserved
NUMBER Segment number being ACK'ed
______________________________________
||1|0 0 0| NUMBER || ACK
-++-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-++- (8xxx hex)
||1|0 0 1| NUMBER || NAK
-++-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-++- (9xxx hex)
6 7 8
8,9 SEGNUM Number of this segment, modulo 4096.
10 DATA Data sent over logical link, transparent.
NSP DATA MESSAGE ________________________________________
(no RTHDR) || | | | * | |NSP data||
++--+--+--+--+--+--+--+--+--+--------++-
1 2 3 4 5 6 7 8 9 10->
NSP DATA MESSAGE (no RTHDR, DDCMP envelope)
_________________________________________________________________
||81xx4xnnmm01yyyy|| | | | * | |NSP data||BLKCK3||
++----------------++--+--+--+--+--+--+--+--+--+--------++---+--++
1 2 3 4 5 6 7 8 9 10->
NSP DATA MESSAGE ________________________________________________
(RTHDR) ||46nnAAmmBB|| | | | * | | data||
++----------++--+--+--+--+--+--+--+--+--+-----++
1 2 3 4 5 6 7 8 9 10->
NSP DATA MESSAGE (RTHDR, DDCMP envelope)
__________________________________________________________________________
||81xx4xnnmm01yyyy||46nnAAmmBB|| | | | * | | data||BLKCK3||
++----------------++----------++--+--+--+--+--+--+--+--+--+-----++---+--++
1 2 3 4 5 6 7 8 9 10->
DAP MESSAGE
_________________________
FORMAT || OPERATOR || OPERAND ||
++----------++---------++
* optional field
______________________________________________________________
OPERATOR || TYPE | FLAGS | STREAMID*| LENGTH*|LEN256*|BITCNT*|SYSPEC*||
++------+-------+----------+--------+-------+-------+-------++
1 2 3 4 5 6 7
1 TYPE Type of DAP message
Hex Oct
01 001 Configuration message
02 002 Attributes message
03 003 Access message
04 004 Control message
05 005 Continue Transfer message
06 006 Acknowledge message
07 007 Access Complete message
08 010 Data message
09 011 Status message
0A 012 Key Definition Attributes Extension message
0B 013 Allocation Attributes Extension message
0C 014 Summary Attributes Extension message
0D 015 Date and Time Attributes Extension message
0E 016 Protection Attributes Extension message
0F 017 Name message
10 020 Reserved for future use
2 FLAGS DAP message flags
Bit 0 STREAMID field present
Bit 1 LENGTH field present
Bit 2 If bit 1 set, LENGTH256 field present
Bit 3 BITCNT field present
Bit 5 SYSPEC field present
3 STREAMID Stream identification field
4 LENGTH Length of OPERAND field, 8-bit bytes
5 LEN256 Extension of LENGTH field
6 BITCNT # of unused bits in last byte of data message
7 SYSPEC System specific flags, maximum length 255 bytes