User's Manual Part 2

166 APCD-LM043-8.0 (DRAFT C)
11: Monitoring the Network
Statistics reported by the CCU can assist in identifying when retransmissions are occurring
and at what rate they are occurring. They can also be used to troubleshoot the cause of
retransmissions.
The statistic
txPayloads gives the total number of transmitted payloads, consisting of
• user data received by the CCU Ethernet port, and transmitted over the radio network,
• user data received from an EUM, that is “switched” to the CCU radio port for
transmission to another EUM,
• MAC control data,
• broadcast data, and
• data retransmitted because it was not acknowledged by an EUM and is assumed lost.
Examining this statistic in more detail,
txPayloads includes
• Tx Data Payloads which, in turn, includes
• data originated by the CCU application and sent to the radio port,
• data coming from the Ethernet port of the CCU (either end-user data or
operator monitoring [SNMP] data),
• data coming from EUM-originated data payloads that have been “switched” to
the CCU radio port (for transmission to other EUMs), and
• broadcast data to all EUMs(
TxPayloadsBCast).
• Tx Ctrl Payloads — Control data generated in the CCU, and used to configure, or
request status from, the EUMs. Tx Ctrl Payloads are transmitted during specific EUM
poll periods.
• Retransmitted data — Data that is not acknowledged after a transmission and is
assumed to be lost or corrupted.
Understanding the relationship between these values helps you monitor the integrity of a CCU
radio environment.
All non-broadcast payloads (hence, “directed” payloads) are explicitly acknowledged by the
EUMs. For these payloads, the result of a transmission during an EUM poll cycle will be one of
the following:
Table 28 Possible Transmission Outcomes
Result of Transmission Reported Statistic
Payload is delivered to an EUM and
acknowledged on the first poll.
txPayloads10k
Payload is transmitted twice, after which an
acknowledgement is received.
txPayloads20k
Payload is transmitted three times, after
which an acknowledgement is received.
txPayloads30k
Payload is transmitted four times, after
which an acknowledgement is received.
txPayloads40k