Specifications

PRIVATE DATATAC SYSTEM PERFORMANCE
Capacity Issues
R4-11-4G Wireless Data Communications Network 1-19
operation, systems engineering develops the message profile as part of the
solution design.
Capacity is rated using a standard message profile consisting of a 50-character
(user data) inbound (IB) message, 100-character (user data) outbound (OB)
message, and equal IB and OB rates. Network capacity is the sum of IB and
OB messages (table 1-2).
Capacity and performance are determined by modeling and simulation only.
The benchmark capacities are useful when providing the customer with
estimates.
Capacity specifications consider the radio protocol link-level
acknowledgments. If the host or mobile computer applications call for
manual acknowledgments as the standard for public safety emergency
dispatches, manual acknowledgments must be treated as user messages.
1.7.1.1 Host Capacity
When the user messaging requirements are determined, the effect on the host
computer must be assessed by systems engineering. This decides if the host
processor can support the additional load that the Private DataTAC network
will introduce. The customer’s systems analyst or host applications vendor
provides this analysis, with input and assistance from the Motorola systems
analyst.
1.7.1.2 Host Link Capacity
The RNC3000 and WNG capacities using a dedicated TCP/IP ethernet host
link is non-blocking to the Private DataTAC network. Non-blocking is a term
that signifies the message capacity specified is higher than the total capacity
that a network configuration can attain.
1.7.1.3 WNG Capacity
WNG capacity, using the standard message profile, is 400K messages per
hour (mph), which equates to approximately four fully-loaded RNC3000s. In
a high availability system design that incorporates a fault tolerant WNG, the
capacity is 250K mph.
Table 1-2. Standard Message Profile
Message
Service
User
Data
Length
Delivery
Service
Direction Quantity
Variable
Length
50
Characters*
Individual
Confirmed
Inbound 50% of total
capacity
Variable
Length
100
Characters*
Individual
Confirmed
Outbound 50% of total
capacity
* Character = one byte; one byte = 8 bits