The enhanced QoS features include source address filtering which removes a packet after it completes the route of a ring network. This is useful for industrial control and automotive applications where ring networks are implemented. The 4-queue traffic prioritization can be per port based, IEEE 802.1p based, or DiffServ based. The DiffServ based prioritization supports both IPv4 and IPv6 classifications. The rate limiting feature of the KSZ8873 supports rates from 64kb per second to 99Mb per second. The rate can be programmed independently for the transmit and receive sides of each port. The tail tag mode support at port 3 adds a byte before the FCS to inform the processor at port 3 which port receives the ingress packet. In this way Microchip is able to reduce the overhead at the processor because the processor does not need to look at the table to find the port information. The KSZ8873 also supports individual MAC addresses for port 1 and port 2 which are used in the routing function. Additonally, there are a couple of features inherited from existing products. These are the LinkMD® TDR-based cable diagnostics utility, used to identify faulty cabling, and the HP Automatic MDI/MDIX crossover support, used to eliminate the need for cross-over cables in certain applications. Finally, as is true with most of Microchip’s Ethernet products, these parts are available in an industrial grade option.