Editing Avionics Full-Duplex Switched Ethernet (section)

==Switching of virtual links==
Each switch has filtering, policing, and forwarding functions that should be able to process at least 4096 VLs. Therefore, in a network with multiple switches (cascaded star topology), the total number of virtual links is nearly limitless. There is no specified limit to the number of virtual links that can be handled by each end system, although this will be determined by the BAG rates and maximum frame size specified for each VL versus the Ethernet data rate. However, the number of sub-VLs that may be created in a single virtual link is limited to four. The switch must also be non-blocking at the data rates that are specified by the system integrator, and in practice this may mean that the switch shall have a switching capacity that is the sum of all of its physical ports.

Since AFDX utilizes the Ethernet protocol at the MAC layer, it is possible to use high performance COTS switches with Layer 2 routing as AFDX switches for testing purposes as a cost-cutting measure. However, some features of a real AFDX switch may be missing, such as traffic policing and redundancy functions.