Question

Is there any interface between mac-pdcp .Do mac layer has to monitor the bytes pending for transmission in the PDCP transmission buffer, for doing the BSR. If yes why should it do.

Answer 1

As per my understanding with 3GPP. No any Interface between PDCP and MAC.

No there is no any need for monitoring the bytes pending for transmission in PDCP transmission Buffer. BSR will be coming from RLC. It will only take care of what RLC is asking. No any link direct link between PDCP and MAC.

Answer 2

Answer is No. There is no interface between MAC to PDCP because based on transmission opportunity from MAC, MAC SDU should be prepared and we know the segmentation is performed by RLC layer. For cell specific information , segmentation is not performed by RLC layer like BCCH, PCCH channel information. PDCP layer is associated to UE. I means SRB1, SRB2 and DRBs but not with SRB0 since pdcp layer has to perform integrity and ciphering. That's why there is no direct interface between PDCP and MAC layer at all.
Please correct me if I am wrong.