Answer: In the IP PDU session type, the IP packets have source and destinations IP addresses in the IP header (e.g., an ipv6 adress is 128bits). As a result, this increases the size of the IP packet header. This is quite inefficient in mMTC and uRLLC use cases of 5G. In the scenario of mMTC, this results in higher overhead for a smaller amount of user data being transferred. Moreover, in the case of uRLLC this may result in increased latency due increased overhead. 3GPP proposed a workaround to this problem by removing the IP header and using ethernet addresses as source and destination addresses to transfer data in a PDU session.

Question: Based on ETSI TS 123 503: Type of PDU Session (IPv4, IPv6, IPv4v6, Ethernet, Unstructured). do you have comments on Unstructured data type usage?

Answer: Thanks. The unstructured PDU session type is rarely used. In case of unstructured PDU session type 5G system does not know what type of protocol is being used at the application layer. UE is not assigned any IP or ethernet addressed by SMF for this pdu session. And data transfer is done using local tunneling mechanism between the entities.