HP Archive Backup System for OpenVMS Guide to Operations

Remote Devices
8.4 Monitoring and Tuning Network Performance
8.4.5 Changing Network Parameters for DECnet-Plus(Phase V)
The Network Control Language (NCL) is used to change DECnet-Plus network parameters. The
transport parameters MAXIMUM RECEIVE BUFFERS, MAXIMUM TRANSPORT CON-
NECTIONS and MAXIMUM WINDOW can be adjusted by using NCL’s SET OSI TRANS-
PORT command. For example:
NCL> SET OSI TRANSPORT MAXIMUM RECEIVE BUFFERS = 4000 !default value
NCL> SET OSI TRANSPORT MAXIMUM TRANSPORT CONNECTIONS = 200 !default value
NCL> SET OSI TRANSPORT MAXIMUM WINDOWS = 20
!default value
To make the parameter change permanent, add the NCL command(s) to the SYS$MAN-
AGER:NET$OSI_TRANSPORT_STARTUP.NCL file. Refer to the DENET-Plus (DECnet/OSI)
Network Management manual for detailed information.
8.4.6 Resource Considerations
Changing the default values of line receive buffers and the pipeline quota to the values of 30 and
45000 consumes less than 140 pages of nonpaged dynamic memory.
In addition, you may need to increase the number of large request packets (LRPs) and raise the
default value of NETACP BYTLM.
Large request packets
LRPs are used by DECnet to send and receive messages. The number of LRPs is governed by
the SYSGEN parameters LRPCOUNT and LRPCOUNTV.
Recommendation:
A minimum of 30 free LRPs is recommended during peak times. Show these parameters and the
number of free LRPs by entering the following DCL command:
Result:
$ SHOW MEMORY/POOL/FULL
System Memory Resources on 24-JUN-1991 08:13:57.66
Large Packet (LRP) Lookaside List Packets Bytes
Current Total Size 36 59328
Initial Size (LRPCOUNT) 25 41200
Maximum Size (LRPCOUNTV) 200 329600
Free Space 20 32960
In the LRP lookaside list, this system has:
• Current Total Size of 36
The SYSGEN parameter LRPCOUNT (LRP Count) has been set to 25. The Current Size is not
the same as the Initial Size. This means that OpenVMS software has to allocate more LRPs. This
causes system performance degradation while OpenVMS is expanding the LRP lookaside list.
The LRPCOUNT should have been raised to at least 36 so OpenVMS does not have to allocate
more LRPs.
Recommendation:
Raise the LRPCOUNT parameter to a minimum of 50. Because the LRPCOUNT parameter is
set to only 25, the LRPCOUNT parameter is raised on this system even if the current size was
also 25.
8-6 Remote Devices