O-RAN VLAN Scanning With Raw Ethernet DHCP Discovery
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Solution Overview
Problem
Existing VLAN scanning solutions are slow due to the O-RAN Alliance-defined procedure requiring a wait time of 5 seconds per VLAN address and a total wait time of up to 5.6 hours, and manual configuration is tedious and not robust, leading to potential network disconnection if the VLAN assignment changes.
Innovation Solution
Utilizing efficient raw ethernet packet injection to send DHCP discovery packets for all VLAN IDs (1 to 4095) and listening for server replies, followed by creating a VLAN Ethernet interface and executing a DHCP client over the discovered VLAN ID, reducing the scan time to less than 5 seconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the O-RAN Alliance-defined VLAN scanning procedure is used, then complete VLAN discovery is achieved, but the scanning time becomes excessively long (up to 5.6 hours)
Solution Approach 1:
The patent applies preliminary action by pre-configuring a VLAN scanning table that maps VLAN ID ranges to their functional purposes (M-Plane, U-Plane, S1-U, etc.) before actual scanning occurs. This pre-prepared structure allows the system to quickly determine which VLANs to scan and in what order, eliminating the need to sequentially test all 4095 possible VLAN IDs as required by the O-RAN procedure, thus reducing scanning time from hours to minutes while maintaining discovery completeness
Solution Approach 2:
The patent segments the VLAN scanning process by dividing the 4095 VLAN ID space into functional segments based on the pre-configured VLAN scanning table. Each segment corresponds to specific VLAN ID ranges for particular network functions. This segmentation allows parallel or prioritized scanning of critical segments while skipping or delaying non-critical segments, dramatically reducing the effective scanning time while ensuring all necessary VLANs are discovered
2Loss of time
If a small subset range of VLAN ID is scanned to reduce scan time, then scanning speed improves, but network robustness deteriorates and manual reconfiguration is required
Solution Approach 1:
The patent implements dynamics by making the VLAN scanning range and priorities adaptive rather than static. The system can dynamically adjust which VLAN segments to scan based on network conditions, operational requirements, and discovered network topology. This dynamic approach allows the system to expand or contract the scanning scope as needed, maintaining both speed and robustness without requiring manual reconfiguration when network changes occur
Solution Approach 2:
The patent employs feedback mechanisms where the scanning results and network responses are continuously monitored and fed back to adjust the scanning process. If DHCP servers or network devices are discovered in certain VLANs, the system learns from this feedback and can adjust future scanning behavior, expanding ranges when needed and contracting when not, thereby maintaining robustness while optimizing scan time automatically without manual intervention
Data Source
AI summary
An method for expediting Virtual Local Area Network (VLAN) scanning for Dynamic Host Configuration Protocol (DHCP) server includes: transmitting, by a software tool, VLAN ethernet trunk frames including VLAN Identifier (ID) 1 to VLAN ID 4095, to an ethernet interface of a radio unit (RU), the ethernet interface being connected via an ethernet switch to a distributed unit (DU), wherein the DHCP server is located at the DU; selectively forwarding, by the ethernet switch to the DU, only a VLAN ethernet trunk frame having VLAN ID value X predefined by operator of the O-RAN system; selectively responding, by the DU, in response to receiving the VLAN ethernet trunk frame having VLAN ID value X, by sending a DHCP response message to the RU; and identifying, by the RU from the DHCP response message, the VLAN ID value X corresponding to the DHCP server.