HP 3000 Manuals

Configuring Systems for Terminals, Printers, and Other Serial Devices

Tuning Your DTC 

This section describes the steps for tuning your DTC by selecting the
AFCP, TCP and management timers that are appropriate for your DTC and
network traffic.  The timer selection is made by choosing a set from a
predefined set of timer values.  The TCP timers are only used for
back-to-back connections from switched DTC ports. 

Figure 8-2  displays the Tune DTC - Timer Configuration screen.  This
screen is reached by pressing [F2], the [Tune DTC] function key at the
DTC Configuration screen.  See the beginning of this appendix to find out
how to access the [Tune DTC] function key. 

The Tune DTC - Timer Selection screen for host-based management is shown
below.  The screen for PC-based management contains only the AFCP timer
selection.  For PC-based management the TCP and management timers are
configured on the DTC OpenView workstation.


          Figure 8-2.  Tune DTC - Timer Selection Screen 

   1.  The DTC name field is a display field and shows the name of the
       DTC you are currently configuring.

   2.  Select one of six predefined sets of values for AFCP timers.  The
       default is selection 1.

   3.  Select one of five predefined sets of TCP timer values.  The
       default is 1.

   4.  Select one of two predefined sets of values for management timer.
       The default is selection 1.  The management protocol timers
       determine different transmission algorithms.

   5.  After you have selected the desired timer values, press the [Save 
       Data] key.

   6.  Press the [Prior Screen] key to return to the DTC Configuration
       screen, or press [Validate DTS/LINK] to validate your
       configuration if you have completed configuration for your DTCs.

       _________________________________________________________________ 

       NOTE  If you changed your network configuration, you need to
             validate the configuration and cross-validate with SYSGEN
             before you exit NMMGR. Refer to chapter 5 for information on
             these steps.

       _________________________________________________________________ 

For host-based management, after you invoke dynamic configuration, both
host and DTC values will take effect once you logoff any sessions or stop
and restart the spooler associated with changed devices and download the
DTC. For PC-based management, only the host values will take effect
because the DTCs are managed by the OpenView DTC Manager on the PC. You
must use the OpenView DTC Manager to configure and download the DTC timer
values.  In this case, you must ensure consistency of timer selections
between the host and the DTC during configuration in NMMGR and OpenView
DTC Manager.

Fields 

AFCP Timer Set 1      Normal timer mode.  This selection is appropriate
                      for most users operating in a normal LAN
                      environment.

AFCP Timer Set 2      Short retransmission timer mode.  This is
                      appropriate in a LAN environment where there is a
                      high number (greater than 1%) of packets lost on
                      the LAN. The values are adapted to provide shorter
                      retransmission values and higher number of retries.

AFCP Timer Set 3      Long retransmission timer mode.  This is
                      appropriate in a LAN environment where the LAN is
                      very reliable.  The values are adapted to reduce
                      LAN traffic and host driver overhead.

AFCP Timer Set 4      Variable retransmission timer mode.  This is
                      appropriate in exceptional cases where there is a
                      very high percentage of lost packets on the LAN.
                      The values are adapted to prevent saturation of the
                      LAN.

AFCP Timer Set 5      MPE XL release 1.2 timer mode.  This is appropriate
                      for use with HP 3000 MPE XL FOS release 1.2.

AFCP Timer Set 6      MPE XL release 2.1 timer mode.  This is appropriate
                      for use with HP 3000 MPE XL FOS release 2.1.

TCP Timer Set 1       Normal timer mode.  For local transaction
                      processing applications and Telnet connections on
                      local LAN.

TCP Timer Set 2       Bridge timer mode.  Same mode as Set 1 but with
                      bridges.  Suitable for LANs with moderate delays.

TCP Timer Set 3       Router/X.25 timer mode.  Same mode as Set 1 but
                      with routers or X.25.  Suitable for LANs with
                      longer delays.

TCP Timer Set 4       High data loss timer mode.  Suitable for networks
                      with high data losses.

TCP Timer Set 5       Heavy traffic timer mode.  Suitable for extended
                      switching applications on local LAN or with bridges
                      where there is heavy traffic.

Management Timer Set  Normal traffic mode.  This is appropriate in a LAN
1                     environment with normal traffic

Management Timer Set  Busy LAN mode.  This is appropriate in a LAN
2                     environment with busy traffic.

MPE/iX 5.5 Documentation