Method of transmission of data in cluster environment

Cluster system having a plurality of cluster units and a switching unit, said cluster units being associated with the same P unicast address, wherein the cluster units are configured to be members of an P multicast group said cluster system comprising:

• means for observing using the IGMP protocol which ports of the switching unit are connected to the cluster units,
• means in the switching unit for observing the MAC destination address of a packet arriving to the switching unit and for checking if said MAC destination address is a MAC multicast address,
• means in the switching unit for observing the P destination address of said packet and for comparing said P destination address to said P unicast address associated with the cluster units,
• means in the switching unit for forwarding of the packet to those ports whose identifiers were previously stored to said memory means as a response to the finding that said P destination address and said P unicast address are the same and said MAC destination address is a MAC multicast address.

A switching unit for cluster system having a plurality of cluster units, said cluster units being associated with the same P unicast address and configured to be members of an P multicast group specific to the cluster system, wherein said switching unit is structured as follows:

• the switching unit includes a plurality of ports,
• said switching system includes a memory storing identifiers of those ports which, using an IGMP protocol, are determined to be connected to the cluster units,
• the switching unit has circuitry and/or a programmed machine to observe the MAC destination address of a packet arriving at the switching unit and check if said MAC destination address is a MAC multicast address,
• if so, the switching unit forwards the packet to those ports connected to the cluster units sharing a MAC multicast address.

A switching unit for cluster system having a plurality of cluster units, said cluster units being associated with the same P unicast address and configured to be members of an P multicast group specific to the cluster system, wherein said switching unit is structured as follows:

• the switching unit includes a plurality of ports,
• said switching system includes a memory storing identifiers of those ports which, based on an IGMP multicast group reports received, are determined to be connected to the cluster units,
• the switching unit observes the MAC destination address of a packet arriving at said switching unit and checks if said MAC destination address is a MAC multicast address,
• if so, said switching unit forwards the packet to those ports connected to the cluster units sharing a MAC multicast address.