Wavenet Technology Pty Ltd. BM2900D Benutzerhandbuch
Appendix D - Application Development __________________________ Boomer II User Manual & Integrator’s Guide
Copyright Wavenet Technology © November 2003
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DataTAC 5000 system is optimised for the transfer of short and
medium length messages. Typically, messages up to 512 bytes are
transferred across the network as a single data packet. Messages larger
than 512 bytes are segmented into 512-byte packets by the DataTAC
system before being transmitted over the air. The packets are
reassembled before they are delivered to the application. For MDC
4800 operation on DataTAC 4000 systems, the segmentation size is
256 bytes.
For example, a 600-byte user message or service data unit (SDU)
results in the delivery of two packets, or protocol data units (PDU), that
are reassembled in the wireless device. Each PDU requires a Radio
Data-Link Access Procedure (RD-LAP) acknowledgment from the
device, which takes a few seconds to complete. The fewer Plus in a
message, the shorter the delivery time. If messages larger than 2 kB are
to be sent across the system, the host and wireless device application
must provide the segmentation and reconstruction functions.
medium length messages. Typically, messages up to 512 bytes are
transferred across the network as a single data packet. Messages larger
than 512 bytes are segmented into 512-byte packets by the DataTAC
system before being transmitted over the air. The packets are
reassembled before they are delivered to the application. For MDC
4800 operation on DataTAC 4000 systems, the segmentation size is
256 bytes.
For example, a 600-byte user message or service data unit (SDU)
results in the delivery of two packets, or protocol data units (PDU), that
are reassembled in the wireless device. Each PDU requires a Radio
Data-Link Access Procedure (RD-LAP) acknowledgment from the
device, which takes a few seconds to complete. The fewer Plus in a
message, the shorter the delivery time. If messages larger than 2 kB are
to be sent across the system, the host and wireless device application
must provide the segmentation and reconstruction functions.
Message Transit Time
The time required for an inbound or outbound message to travel across
the network is primarily a function of the queuing delays associated
with each product in the network infrastructure and the message load
on the system. As system traffic builds, queuing delays increase for
outbound traffic, while the average time to access the inbound channel
increases, resulting in longer inbound message transit times.
Additional delays are encountered when the wireless terminal is in the
process of roaming from one cell on one radio channel to a cell on
another radio channel. If the cells are controlled by the same cell
controller, the delay time is quite short. The delay time can increase if
the cells are controlled by different cell controllers on different sub
networks.
For a DataTAC 5000 fixed-end system operating at full rated capacity,
the mean transit delay between a network host and a wireless device is
typically no more than four seconds.
The application developer must develop operational scenarios to
accommodate the variable transit time in the application design.
The time required for an inbound or outbound message to travel across
the network is primarily a function of the queuing delays associated
with each product in the network infrastructure and the message load
on the system. As system traffic builds, queuing delays increase for
outbound traffic, while the average time to access the inbound channel
increases, resulting in longer inbound message transit times.
Additional delays are encountered when the wireless terminal is in the
process of roaming from one cell on one radio channel to a cell on
another radio channel. If the cells are controlled by the same cell
controller, the delay time is quite short. The delay time can increase if
the cells are controlled by different cell controllers on different sub
networks.
For a DataTAC 5000 fixed-end system operating at full rated capacity,
the mean transit delay between a network host and a wireless device is
typically no more than four seconds.
The application developer must develop operational scenarios to
accommodate the variable transit time in the application design.