Other than throughput KPIs, what should be monitored?
Latency and eRAB setup time.
Mute call for VoLTE.
If you change for VoLTE QCI as well linked with PDCP for QCI1.
Aha, VoLTE is not activated in my network.
Any potential impact on CSFB?
Ok, then no issue - No impact on CSFB.
Keep trial in cluster of site or small area to monitor.
Check hourly, dbh as well.
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I have a lone site with huge traffic. I will start with it. 
Yes look for worse site with high latency and low throughput, so can target site like this where less chance of degradation in throughput.
Throughput will not be the highest impacted KPI, you should watch out for Packet Loss! Most likely it will skyrocket at discardtimer 150ms
Summary: a good value is to keep at 750 ms.
A large value of this parameter results is a long delay of services and a failure to meet the QCI requirement. A smal value leads to severe cause of PDCP data discarding and therefore low throughput.
It was set to 150 ms, we recommended to increase to 300 ms as it is too early to discard the packet.
But this is used for VoLTE in ROHC feature.
Small value recommend for VoLTEe call to reduce mute call rate.
For PS call it’s recommended high value.
750 ms is too high, 150 or 300 are much better than 750.
To trade off between Latency and PDCP discard timer value generally recommend to keep mid value 750 ms…
Max we can go upto infinity 
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Yes, correct.
I think we can link QCI per PDCP profile so QCI1 can be link with PDCP profile for VoLTE having shorter value.
QCI 9,8 for non GBR linked with PDCP profile, for PS with optimized value for PDCP discard.
For E///, lower value are recommended.
Ok, may differ vendor wise if you set lower values.
Please check PDCP packet discard rate.
Is it increasead and corresponding throughput impacted?
In Nokia,for audio gaps detection, default is 5s which is too high compared to Ericsson.
But you can reduce till 500 ms.
Infinity too high it will impact latency actually use of this timer is like once PDCP PDU pass to lower layer then PDCP start timer and wait for response from RLC layer.
So if we keep lower value of timer, then it get expired early leading to packet discard fast, but will improve latency.
Higher value suggest to improve throughput, mute call but it lead to increase in latency.
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Hi all.
What is the proposition for pdcp discard timer if um rlc is used for bearer?