How UE will start timer t300 when sending RRC connection request and How this scenario will happen?

Question

After sending RRC connection request message how much time UE will wait to receive RRC connection setup or reject message.

Answer 1

UE gets t300 timer value from SIB2. UE reads SIB2 before attach.

Answer 2

T300 starts at the RRC connection REQ transmit and stops at the Receipt of RRC connection setup or reject message OR at the cell reselection time OR upon abortion of connection establishment by Higher layers (L2/L3).

At the expiry UE retransmits RRC connection REQ if V300 =< N300, else go to Idle mode.

Comments

I want who will give t300 timer value to UE from where it will it take

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must be via some config (not sure) and possible values are 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000, 3000, 4000, 6000, 8000 ms.

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is it from Sib2?

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not sure ???

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UE-RRC gets T300 value from the IE timersAndConstans present in SIB-2.