OPERATION
AND
APPLICATION
UNILINK HOST
ADAPTER2–47
USER MANUAL
2.10.10.3 Adjusting
An HIUs Bandwidth
The REPORT NETWORK BANDWIDTH ALLOCATION command, code 36,
returns counters that reflect the relative network activity for a specific HIU.
The counters do not reset after reaching their maximum value and must be
explicitly
reset.
Although the HIUs on the network have no direct control over the number of
Network
Manager buffers allocated to them, they
can control how those buffers
are used with the ALLOCATE HIU BANDWIDTH command. This command
defines
how the buffers are to be divided between direct requests/non-repetitive
macros and repetitive macros by specifying how many of the allocated buffers
will
be used for repetitive macros. By default, repetitive macros
can use all of the
NM buffers allocated to the HIU. This command also limits the number of
outstanding requests for a single secondary device, preventing one secondary
from dominating the entire bandwidth. The default for this parameter is the
smaller
of two requests per secondary or the number of NM buffers allocated to
the HIU. Both parameters are single bytes ranging from 00 to the number of
NM buffers allocated to the HIU. The command code will be returned if the
command
is accepted. Y
our applications software may issue this command more
than once in order to change the parameters to match the demands as they
change.
Issue
the REPORT HIU BANDWIDTH ALLOCA
TION command to
determine
the buffer allocation and retrieve macro statistical counters. The statistical
counter parameters are long words that must be explicitly reset when they
reach
their maximum values. The command
string includes the command code
and
the optional reset counters code.
There are two sets of counters, one for repetitive macros and the other for
non-repetitive macros. The first counter in each set counts the number of
I-Frame
pairs sent and received by the macro type. The second counter in each
set counts the number of I-Frame bytes sent by the macro type. The third
counter in each set counts the number of I-Frame bytes received by the macro
type. These counts do not include any HDLC overhead or communications
counts between the NM and the HIU. Reset these counters by sending the
command string 1A 01. The adapter will return the command code 1A if
accepted.