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Reply To: TBF Establishment Failure Rate :


hi ayat,

Yes i understand what you mean. I agree it is very surprising, and the most probable answer is that ZTE is not properly pegging the number of TBF request. They may be pegging a TBF request (counter) only after the TBF has been allocated (hence, no congestion).

That’s the obvious answer.

Now there’s another possibility : it may be that ZTE default GPRS parameters allow for a huge piling up of TBF over the same PDCH, which allows to minimize TBF congestion at the cost of TBF throughput.
You can look at followning kpi to be sure :
* avg PDCH per TBF during BH (will be around 1)
* avg TBF per PDCH during BH (will be higher than 6)
* avg throughput per TBF (will be around 10kbps)
* avg throughput per cell & dl volume transmitted (will be comparable with huawei cells)

Other thoughts :
– check the specific counter that pegs when there is tbf congestion (like a number of tbf block, or a time during which there is tbf congestion). Compare that value with number of tbf success, and do you own ratio.
– maybe all tbf congestion is counted in Uplink, and you’re looking at downlink Kpi.

That’s all i can think of 😉