Methods and devices for switching data frames in a communications network

A source switch device for switching data frames in a communications network comprising a plurality of switch devices including the source switch device, the source switch device having a switch identity (switch ID), the source switch device comprising a processor and a memory, the memory containing instructions executable by the processor whereby the source switch device is operative to:

• receive a data frame from a source host node that is connected to the source switch device, wherein the data frame includes a source Media Access Control (MAC) address of the source host node, and a destination MAC address;
• modify the received data frame by modifying a part of the source MAC address in the received data frame with information comprising:
• the switch ID, a port number indicating a port of the source switch device from which the data frame is received, and a reference number representing the part of the source MAC address in the received data frame;
• determine if there is a table in the source switch device:
• if it is determined that there is a table in the source switch device, and if the table in the source switch device does not include the reference number and the part of the source MAC address:
• include the reference number and the part of the source MAC address in an entry of the table;
• if it is determined that there is no table in the source switch device:
• generate a table and including in an entry of the generated table the reference number, and the part of the source MAC address;
• and
• if the received data frame is an Address Resolution Protocol (ARP) request message:
• further modify the modified data frame by replacing a sender MAC address indicated in the received data frame or in the modified data frame with the modified part of the source MAC address;
• and
• flood, towards a destination host node, the further modified data frame, to at least one switch device of the plurality of switch devices.

A transit switch device for switching data frames in a communications network comprising a plurality of switch devices including the transit switch device, wherein the transit switch device comprising a processor and a memory, the memory containing instructions executable by the processor whereby the transit switch device is operative to:

• receive a modified data frame from a source switch device, wherein the data frame is modified from a data frame including a source Media Access Control (MAC), address of a source host node and a destination MAC address, by modifying a part of the source MAC address in the data frame with information comprising:
• a switch ID, a port number indicating a port of the source switch device from which the data frame is received, and a reference number representing the part of the source MAC address in the data frame;
• fetch from the part of the source MAC address of the received modified data frame, the switch ID;
• determine if there is a switch table in the transit switch device:
• if it is determined that there is no switch table in the transit switch device:
• generate a switch table, and include in the generated switch table the fetched switch ID and a port number indicating a port of the transit switch device from which the modified data frame is received;
• if it is determined that there is a switch table in the transit switch device, and if the switch table in the transit switch device does not include the fetched switch ID and does not include the port number indicating the port of the transit switch device from which the modified data frame is received:
• include in the switch table the fetched switch ID and the port number indicating the port of the transit switch device from which the modified data frame is received;
• and
• if the received modified data frame is an Address Resolution Protocol (ARP) request message:
• flood, towards a destination host node, the modified data frame to at least one switch device of the plurality of switch devices.

A destination switch device for switching data frames in a communications network comprising a plurality of switch devices including the destination switch device, wherein the destination switch device comprising a processor and a memory, and the memory containing instructions executable by the processor whereby the destination switch device is operative to:

• receive a modified data frame from a transit switch device, wherein the modified data frame is modified from a data frame including a source Media Access Control (MAC) address of a source host node and a destination MAC address, by modifying a part of the source MAC address in the data frame with information comprising:
• a switch ID, a port number indicating a port of a source switch device from which the data frame is received, and a reference number representing the part of the source MAC address in the data frame;
• fetch from a part of the source MAC address of the received modified data frame, the switch ID;
• determine if there is a switch table in the destination switch device:
• if it is determined that there is no switch table in the destination switch device:
• generate a switch table, and include in the generated switch table the fetched switch ID and a port number indicating a port of the destination switch device from which the modified data frame is received;
• if it is determined that there is a switch table in the destination switch device, and if the switch table in the destination switch device does not include the fetched switch ID and does not include the port number indicating the port of the destination switch device from which the modified data frame is received:
• include in the switch table the fetched switch ID and the port number indicating the port of the destination switch device from which the modified data frame is received;
• and
• if the received modified data frame is an Address Resolution Protocol (ARP) request message:
• flood the received modified data frame to at least a destination host node device that is connected to the destination switch device.