Case 3: nCELL - T5000 - TCP UL Low Throughput

Issue Description:

TCP UL speed test is low as below.

Achieve Network Topology and NE Information
Standard Networking.

Suggested Troubleshooting Methods:
a) Check the radio interface environment by pre-scheduling.
b) Determine if insufficient dispatch/Low MCS/ low RANK by mac-layer print watching.
c) Determine if transmission bandwidth is restricted by UDP testing.
d) Configuration parameter check by web check and xml comparation.
e) Gather log +User Plane + FAPI log analysis.
f) Collect CPE QXDM log

Troubleshooting Procedures:
a) Open UL pre-scheduling and observed full dispatch and good speed.

UL UDP iperf test, speed is good.

UL TCP Iperf test with 5 thread, speed is low.

When do iperf test with 50 thread, it can achieve good speed sometimes, but degraded some time later. It indicates insufficient sending traffic.

b) Check the configuration parameter and compare. Parameter “PeriodicBsrTimer” was not modified properly, This is a cell level parameter, need modify the value from sf20 to sf5 for all cells.

After modify the parameters, UL throughput restored to normal.

Conclusion:
Parameter “PeriodicBsrTimer” decides the frequency of UL sending frequency.
Applicable to all the Low UL Throughput case, need be check in high priority.

 Troubleshooting Methods: Download