User's Manual

3 Detailed Description
APCD-LM043-4.0 41
Table 8 Factory Default GOS Configuration File
NOTE: While recognizing that the performance of data transmission
through packet radio networks is randomly dependent on many
variables, typical FTP rates based on empirical data are included
in the table to demonstrate the performance that the operator
might expect on single, large FTP transfers using maximum-sized
packets.
There are several important observations that can be made about the above service-class
descriptions:
• All of the default service classes impose a limit on the maximum polling rate.
• The Silver and Gold service classes have a lower bound on the polling rate (12 and 22
polls per second [pps] respectively). The Polling MAC treats this limit as a minimum
committed level, which is subject to overall radio link capacity.
• In determining the order and frequency with which to poll EUMs, the CCU first tries to
ensure all associated EUMsarepollednomorefrequentlythanthemaximumservice
class polling rate, and no less frequently than the minimum service class polling rate.
• As the system usage increases, the end-user throughput in all classes decreases
from the maximum. Bronze users see the largest reduction, then Gold users, and then
Best Effort users. When all users have been reduced to 256 kbps (the minimum
threshold for Gold), the next reduction will be shared by the Best Effort, Bronze, and
Silver class users (Gold will not be reduced further), until the minimum threshold for
Silver is reached. After this, if further reductions are required, this reduction would be
shared equally between the Best Effort and Bronze users.
In practice, the bursty nature of Internet usage is such that this methodical reduction in
throughput is not apparent to the end-user, and these variations in service level tend
to be instantaneous and transitory. Overall, end-users tend to see a relatively high
average throughput consistent with their assigned GOS class, as is shown later in
detailed simulation results based on real user data.
Service
Class
Polling Rate (polls/second)
FTP Rate
(see note)
Operator
Assigned
BestEffort 1-34 0-384kbps Yes
Bronze 1 - 90 0 - 1024 kbps Yes
Silver 12 - 22 128 - 256 kbps Yes
Gold 22 - 46 256 - 512 kbps Yes
Broadcast
Varies with channel load,
from 16 to 935
Not applicable No
Denied 0 0 Yes