This allows the user to modify the NETBIOS operational parameters by using the DIR.OPEN.ADAPTER command.
The parameters must be provided at open time and for each NCB.RESET command. If any of these parameters causes an error, the command will terminate with a CCB_RETCODE or NCB_RETCODE as follows:
• If a DIR.OPEN.ADAPTER command, the CCB_RETCODE is X1101. This can occur if the
NCB_MAX_NAMES or NCB_MAX_SESSIONS values are not less than 255, or if there is insufficient work space available to satisfy the values of NCB_STATIONS, NCB_MAX_NAMES, NCB_MAX, and
NCB_MAX_SESSIONS.
• If a NETBIOS command, the NCB_RETCODE is X I FC I . This can occur if any of the remaining parameters are found to be invalid when NETBIOS issues its DLC.OPEN.SAP command.
OFF- PARAMETER NAME BYTE 8086 DESCRIPTION
SET LEN TYPE
0 4
--
Adapter work area4 NCB_TIMER_T1 1 DB T1 value (response timer)
5 NCB_TIMER_T2 1 DB T2 value (acknowledgment timer)
6 NCB_TIMER_TI 1 DB Ti value (inactivity timer)
7 NCB_MAXOUT 1 DB Maximum transmits without a receive acknowledgment
8 NCB_MAXIN 1 DB Maximum receives without a transmit acknowledgment
9 NCB _ MAXOUT -,NCR 1 DB Dynamic window increment value
10 NCB _ MAX_ RETRY 1 DB N2 value
11 1 DB Adapter work area
12 3 Reserved
15 NCB_ACCESS _PRI 1 DB Ring access priority
16 NCB_STATIONS 1 DB Maximum NETBIOS link stations
17 19
--
Adapter work area36 NCB_MAX_NAMES 1 DB Maximum names in names table
37 NCB_MAX 1 DB Maximum outstanding NCBs
38 NCB_MAX_SESSIONS 1 DB Maximum sessions
39 Reserved 1 DB
40 Reserved 1 DB
41 NCB_OPTIONS 1 DB Various options
42 NCB_POOL_LENGTH 2 DW Length of area at NCB_POOL_ADDRESS
44 NCB_POOL_ADDRESS 4 DD Starting segment of Message work area 48 NCB_TRANSMIT_TIMEOUT 1 DB Time to wait for one query
49 NCB _ TRANSM IT_COUNT 1 DB Maximum number of times to transmit queries
NCB_TIMER_T1
Explanation: Specifies the time period between 1 and 10 used to determine an inoperative condition on a link. The time intervals are defined by the DIR.OPEN.ADAPTER command. If the value is zero, the default of 5 is used. See "DLC Timers" on page 4-12.
NCB_TIMER_T2
Explanation: Specifies the time period between 1 and 10 used to delay transmission of an
acknowledgment for a received I-LPDU for link stations using this SAP. The time Intervals are defined by the DIR.OPEN.ADAPTER command. If the value is zero, the default of 2 is used. If the value is greater than 10, the acknowledgment timer is not implemented and acknowledgments will be sent at the earliest
opportunity. See "DLC Timers" on page 4-12.
NCB_TIMER_Ti
Explanation: Specifies the time period between 1 and 10 used to determine an inactive condition on a link.
The time intervals are defined by the DIR.OPEN.ADAPTER command. If the value is zero, the default of 3 is used. See "DLC Timers" on page 4-12.
NCB_MAXOUT
Explanation: Specifies the maximum number of sequentially numbered transmitted I-LPDUs that a link station on NETBIOS SAP may have outstanding at anyone time. The maximum valid value is 127. If the value is zero, the default of 2 is used.
NCB_MAXIN
Explanation: Specifies the maximum number of sequentially numbered received I-LPDUs that a link station on NETBIOS SAP may receive prior to sending an acknowledgment. The maximum valid value is 127. If the value is zero, the default of 1 is used.
NCB _MAXOUT -,NCR
Explanation: This dynamic window increment value, is used to reduce bridge congestion. If the two end points of a session are on different rings, and the adapter detects an error condition requiring
retransmission, the MAXOUT counter will be set to 1. It will then be incremented by one each time MAXOUTJNCR frames are acknowledged by the remote station, until it reaches the value of this field. If this field is set to a value of zero, the default of one is used. For more details, see the IBM Token-Ring Network Architecture Reference.
NCB_MAX_RETRY
Explanation: Specifies the number of retries for an unacknowledged command LPDU, or in the case of an I-LPDU timeout, the number of times that the non-responding remote link station will be polled with an RR/RNR command LPDU. The maximum valid value is 255. If the value is zero, the default of 8 is used.
NCB _ACCESS _PRI
Explanation: The transmit access priority value to be placed in the AC byte of all transmissions from the link station and SAP. The format is B'nnnOOOOO', where 'nnn' is the access priority value. No checking is done and the low-order 5 bits are ignored. If the access priority is higher than allowed for the adapter, the error will be detected on the first transmission.
NCB_STATIONS
Explanation: The number of link stations that may be active at one time. This value must not exceed the value of DLC_MAX_STATIONS. During execution of an NCB.RESET command, this value must not exceed the current number of available link stations. If the value is zero, the default of 6 is used.
NCB_MAX_NAMES
Explanation: The maximum number of names that may be in the name table. The adapter itself is entered as a name, using one of the positions. The maximum valid value is 254. If the value is zero, the default of 17 is used.
NCB_MAX
Explanation: The number of NCBs that may be outstanding at one time.
Note: This value indicates the number of "no-wait" and "wait" commands that may be issued.
The maximum valid value is 255. If the value is zero, the default of 12 is used.
NCB _MAX_SESSIONS
Explanation: The maximum number of sessions that may be active at one time. The maximum valid value is 254. If the value is less than the value of NCB_STATIONS, the NCB_STATIONS value is used.
NCB_OPTIONS
Explanation: Various options, each represented by a bit. If the bit has a value of B'1', the option is active.
The high-order bit is the leftmost bit, 7.
• Bit 7 is "auto open."
When received by the adapter system interface, bit 7 causes an NCB.RESET command to close and then open the adapter. If bit 7 is zero, the NCB.RESET command will not perform the close and will ignore the fields containing the "number of sessions" and the "number of commands." (They remain as defined in the DIR.OPEN.ADAPTER command.)
• Bit 6 is reserved.
• Bit 5 is "this ring only."
When this bit is set on, NETBIOS will assume that all nodes are on the same ring.
• Bits 4 - 0 are reserved.
NCB_POOL_LENGTH
Explanation: The number of bytes of system memory assigned by the application for the NETBIOS
work-area pool. If the value is zero, NETBIOS internal work-area in system memory as defined at load time is used.
NCB_POOL_ADDRESS
Explanation: The starting address of the NETBIOS work-area pool for the adapter support software to build tables, buffers, and control blocks. If the NCB_POOL_LENGTH value is zero, this parameter is ignored.
NCB _TRANSMIT_TIMEOUT
Explanation: A value to define the amount of time that NETBIOS will wait for a response to a private query on the network (such as an "add name query"). The value is in half-second increments. A value of 10 represents a time of 5 seconds. If the value is zero, the default of 1 (1/2 second) is used. If the value is greater than 20, 20 (10 seconds) is used.
NCB_TRANSMIT_COUNT
Explanation: A value to define the number of times that private network queries, such as an "add name query," will be transmitted for a given command. If a query is transmitted more than one time, the next one is transmitted after the NCB_TRANSMIT_TIMEOUT expires. If the value is zero, the default of 6 is used. If the value is greater than 10, 10 is used.