Worst-case backlog for AFDX network with n-priorities

In most recent avionics systems, AFDX (Avionics Full Duplex Switched Ethernet) is the network used to replace the previously employed point-to-point networks. AFDX guarantees bandwidth reservations by means of virtual links which can be classified with two priority levels. AFDX compliant switches implement output buffers at each switch output port. The stored frames leave each output port according to a fixed priority FIFO policy. Overflow of these buffers must be avoided at all cost to prevent data loss. Although the AFDX standard determines the minimum buffer size dedicated to an output port, the actual length of each priority buffer, is a designer decision. Previous works address the worst case backlog of ADFX buffers of one and two priorities. In this work we assume an extended AFDX network in which virtual links can be classified into n-priorities and present the problem statement to compute an upper bound on the worst case backlog faced by each buffer of each output port in each switch of the network.