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AU - Administrative Unit

An Administrative Unit is created during the process of forming the payload of an STM-1. The AU contains a pointer which identifies where in the payload the VC-4 (Virtual Container-4) data begins, thus differentiating between padding and data. The task of the AU is to provide adaptation between the Higher Order Channel Layer and the Multiplex Section Layer.


  • Fully interactive 3GPP based network map
  • Narrated call flows
  • Detailed network procedures

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