The Allied Telesis UniDirectional Link Detection (UDLD) License is designed for the AT GS924MX Switch, CentreCOM AT - GS924MX Switch, and AT - GS948MX Switch. This software product enhances network reliability by detecting unidirectional links, ensuring that network traffic flows correctly and preventing potential network issues. The license is easy to install and manage, making it an essential addition for maintaining optimal network performance.