User guide

Understanding Bandwidth Management Link Characteristics
88
pmp-0229 (Mar 2013)
This tab in the AP and BHM sets the priorities for the various packets in the downstream (sent
from the public network). This tab in the SM and BHS sets the priorities for the various packets in
the upstream (sent to the public network).
Typically, some SMs attach to older devices that use the ToS byte as originally formatted, and
others to newer devices that use the DSCP field. The default values in the Diffserv tab allow your
modules to prioritize traffic from the older devices roughly the same as they traditionally have.
However, these default values may result in more high-priority traffic as DSCP fields from the
newer devices are read and handled. So, after making any changes in the Diffserv tab, carefully
monitor the high-priority channel for high packet rates
• in SMs that you have identified as those to initially set and watch.
• across your network when you have broadly implemented Code Point values, such as via
SNMP.
Traffic Scheduling
This release requires APs, BHs, and AES SMs to be Series P9 or later hardware.2
The characteristics of traffic scheduling in a sector are summarized in Table 21.
Table 21: Characteristics of traffic scheduling
Category Factor Treatment
Throughput
Aggregate throughput, less
additional overhead
14 Mbps
Latency
Number of frames required
for the scheduling process
1
Round-trip latency
1
≈ 6 ms
AP broadcast the download
schedule
No
2
See Designations for Hardware in Radios on Page 381.