Method and apparatus for preventing head of line blocking in an ethernet system

A network interface card (NIC) comprising:

• an interface unit to a data processing unit with which the network interface communicates;
• a congestion status detector for detecting whether there is traffic congestion between the network interface and the data processing unit;
• and
• a congestion status information generator for generating a data frame containing congestion status information for at least two different network interface traffic classes independently at substantially the same time, and sending the data frame containing the congestion status information to an Ethernet switch.

A semiconductor chip comprising:

• an interface unit to a data processing unit with which the network interface communicates;
• a congestion status detector for detecting whether there is traffic congestion between the network interface and the data processing unit;
• and
• a congestion status information generator for generating a data frame containing congestion status information for at least two different network interface traffic classes independently at substantially the same time, and sending the data frame containing the congestion status information to an Ethernet switch.

An Ethernet line card, comprising:

• at least one network interface that includes:
• an interface unit to a data processing unit with which the network interface communicates,
• a congestion status detector for detecting whether there is traffic congestion between the network interface and the data processing unit, and
• a congestion status information generator for generating a data frame containing congestion status information for at least two different network interface traffic classes independently at substantially the same time, and sending the data frame containing the congestion status information to an Ethernet switch;
• at least one CPU communicating data with the at least one network interface;
• and
• an Ethernet switch communicating between the at least one network interface and the Ethernet.

A method for controlling traffic flow in an Ethernet system, wherein the Ethernet system comprises an Ethernet switch that communicates with a network interface, and the network interface communicates with a data processing unit, the method comprising:

• detecting traffic congestion status between the network interface and the data processing unit;
• generating a data frame containing congestion status information for at least two different network interface traffic classes independently at substantially the same time;
• and
• transmitting the data frame containing the congestion status information to the Ethernet switch.