5G Baseband Unit MSS Control to Prevent IP Fragmentation
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Solution Overview
Problem
IP fragmentation occurs when application packets between the 5G core network and the baseband unit exceed the maximum transmission unit (MTU), leading to performance degradation due to fragmentation and defragmentation processes.
Innovation Solution
Adjusting the maximum segment size (MSS) value of the TCP three-way handshake packets to limit the length of application packets, specifically modifying the MSS value to 1100 bytes to prevent IP fragmentation by encapsulating the packets with a GTP header and UDP header, and recalculating the TCP checksum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If application packets are encapsulated with GTP header and UDP header, then the packets can be transmitted between 5GC and BBU, but the packet length exceeds the MTU of intermediate nodes causing IP fragmentation
Solution Approach 1:
The patent modifies the MSS value in TCP three-way handshake packets before actual data transmission begins. By setting the MSS to 1100 bytes during the handshake phase, the system preliminarily establishes packet size constraints that prevent IP fragmentation in subsequent transmissions. This preliminary action ensures that all subsequent packets will fit within the MTU of intermediate nodes without requiring fragmentation.
Solution Approach 2:
The patent changes the MSS parameter value from its default setting to a specific value of 1100 bytes. This parameter modification is performed by intercepting and modifying TCP handshake packets at the BBU level. By changing this critical parameter before transmission, the system ensures that encapsulated packets (with GTP and UDP headers) will not exceed the MTU of intermediate network nodes, thereby preventing IP fragmentation.
2Productivity
If IP fragmentation occurs, then packets can be transmitted despite size constraints, but system performance degrades due to defragmentation processes
Solution Approach 1:
The system performs MSS modification during the TCP three-way handshake before actual data transmission. This preliminary configuration ensures that all subsequent packets are sized appropriately to avoid fragmentation, eliminating the need for time-consuming defragmentation operations and maintaining high system throughput.
Solution Approach 2:
By properly configuring the MSS parameter in advance, the system skips the entire fragmentation and defragmentation process. Packets are transmitted in their final, non-fragmented form directly through the network, rushing through the transmission process without the overhead of splitting and reassembling packets at intermediate nodes.
Data Source
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AI summary
A transmission method for a baseband unit (BBU) of a 5G network system includes determining, by a user-plane program, a modified maximum segment size (MSS) value of transmission control protocol (TCP) connection for the BBU of the 5G network system; and modifying, by the user-plane program, an original MSS value with the modified MSS value for encapsulation during a TCP three-way handshake procedure; wherein the modified MSS value is related to a packet length of an application packet between the UE and an application (APP) server of the 5G network system.