User`s guide

Configuring WAN Connections
Connection profiles
1-18 Preliminary January 30, 1998 Pipeline User’s Guide
For a discussion about removing the base channel in response to reduced
bandwidth requirements, see “Clearing a call on the basis of idle bandwidth” on
page 1-19. For the recommended method of bringing down inactive connections
on the basis of idle time, see “Session options” on page 1-11.
Guidelines for configuring DBA
For optimum MP+ performance, both sides of a connection must have the
following parameters set to the same values:
• Base Ch Count (in the Connection profile)
• Min Ch Count (in the Answer profile and the Connection profile)
• Max Ch Count (in the Answer profile and the Connection profile)
Other considerations for configuration of dynamic bandwidth allocation include:
• The values for the Sec History, Add Pers, and Sub Pers parameters should be
set to ignore spikes in bandwidth utilization that last for a shorter time than it
takes to add capacity.
Over ISDN lines, the Pipeline can add bandwidth in less than five seconds.
• Once the Pipeline adds bandwidth, a minimum usage charge typically
applies. Thereafter, billing is time sensitive.
The Sub Pers value should be at least equal to the time billed for the
minimum duration charge plus one or two billing time increments. Typically,
billing is done to the next multiple of six seconds, with a minimum charge
for the first thirty seconds. Your carrier representative can help you
understand the billing structure of their switched tariffs.
• Channels should not be added or removed too quickly (less than 10-20
seconds apart).
Adding or removing channels very quickly leads to many short-duration
calls, each of which incurs a charge from the carrier. In addition, adding or
removing channels too quickly can affect link efficiency, because the devices
on either end have to retransmit data when the link speed changes.
Monitoring DBA
The DBA Monitor parameter enables you to specify which side of the link
monitors traffic. Only the initiating side, however, can add or subtract bandwidth.