What is SDAP in 5G?
My friend: Hi Soumya, I have a question.
Me: Go ahead.
My friend: What is SDAP in 5G?
Me: It is the highest layer in the protocol stack of 5G user plane located at both gNB and UE. It is a newly introduced protocol in 5G that was not available before in 4G.
My friend: So, what is the function of SDAP?
Me: The primary task of the SDAP protocol is to map each QoS flow into a specific Data Radio Bearer (DRB). Multiple QoS flows can be mapped into a single DRB or a single QoS flow can be mapped into a single DRB based on the QoS needed for each QoS flow. So, assuming we are in the DL direction, the SDAP layer at the gNB side will map all QoS flows coming from UPF to DRBs and then these DRBs are transmitted via air interface to UE. While if we are in the UL direction, so the SDAP layer at the UE side will map all the QoS flows coming from the higher layers of the UE into DRBs to be transmitted at the air interface towards the gNB. Also, SDAP layer adds header info to the DL data packets when reflective QoS is enabled to let the UE use the DL QoS in UL as well.
My friend: Thanks a lot.
Me: You are welcome.
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My friend: Hi Soumya, I have a question.
Me: Go ahead.
My friend: What is SDAP in 5G?
Me: It is the highest layer in the protocol stack of 5G user plane located at both gNB and UE. It is a newly introduced protocol in 5G that was not available before in 4G.
My friend: So, what is the function of SDAP?
Me: The primary task of the SDAP protocol is to map each QoS flow into a specific Data Radio Bearer (DRB). Multiple QoS flows can be mapped into a single DRB or a single QoS flow can be mapped into a single DRB based on the QoS needed for each QoS flow. So, assuming we are in the DL direction, the SDAP layer at the gNB side will map all QoS flows coming from UPF to DRBs and then these DRBs are transmitted via air interface to UE. While if we are in the UL direction, so the SDAP layer at the UE side will map all the QoS flows coming from the higher layers of the UE into DRBs to be transmitted at the air interface towards the gNB. Also, SDAP layer adds header info to the DL data packets when reflective QoS is enabled to let the UE use the DL QoS in UL as well.
My friend: Thanks a lot.
Me: You are welcome.
Please press the like and share buttons to clear it for everyone.
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