Multicast Traffic Management in a Network Interface

Abstract

A method for filtering in a network interface of a computer system multicast packets in a manner that reduces or obviates altogether the processing of unwanted multicast packets by the processing unit of the computer system. Filtering in the network interface is accomplished by the network interface accessing multicast traffic request information originating in the computer system and comparing the accessed information with the multicast destination address and IP source address of packets received in the network interface.

1 . A method of filtering multicast packets in a network interface situated between and coupled to a multicast data network and a bus of a computer system, the computer system having a first memory, the method comprising:
 storing for the network interface and a multicast group address information in the first memory for the purpose of enabling or disabling transmission through the network interface to the bus of the computer system multicast packets sent from sources using the multicast group address, the information comprising first data that identifies the network interface, second data that identifies the multicast group address, third data that denotes an INCLUDE filter-mode or an EXCLUDE filter-mode, and fourth data that identifies a source-list of zero or more IP source addresses,   the network interface accessing the second, third and fourth data,   receiving in the network interface a multicast packet from the multicast data network,   determining in the network interface the multicast group address and IP source address of the multicast packet, determining in the network interface if transmission of the multicast packet from the network interface to the bus is to be enabled or disabled by comparing the multicast group address and the IP source address of the multicast packet with the accessed second, third and fourth data; and   upon determining that the transmission of the multicast packet is to be enabled, the network interface transmitting the multicast packet to the bus, or upon determining that the transmission of the multicast packet is to be disabled, the network interface not transmitting the multicast packet to the bus.   
     
     
         2 . A method according to  claim 1 , wherein accessing of the second, third and fourth data by the network interface is accomplished by the network interface reading the second, third and fourth data from the first memory. 
     
     
         3 . A method according to  claim 2 , wherein the network interface uses direct memory access (DMA) to read the second, third and fourth data from the first memory. 
     
     
         4 . A method according to  claim 1 , wherein accessing of the second, third and fourth data by the network interface is accomplished by the network interface copying the second, third and fourth data from the first memory into a second memory of the network interface. 
     
     
         5 . A method according to  claim 1 , wherein accessing of the second, third and fourth data by the network interface is accomplished by the computer system sending from the first memory the second, third and fourth data to the network interface for storage in a second memory of the network interface. 
     
     
         6 . A method according to  claim 5 , wherein a driver installed on the computer system sends from the first memory the second, third and fourth data to the network interface. 
     
     
         7 . A method according to  claim 1 , wherein the storing of the information in the first memory is accomplished by an IPMulticastListen operation. 
     
     
         8 . A method according to  claim 1 , wherein the accessing of the second, third and fourth data by the network interface is accomplished by an IPMulticastListen operation in the computer system that sends the second, third and fourth data to the network interface for storage in a second memory of the network interface. 
     
     
         9 . A method according to  claim 1 , wherein the storing of the information in the first memory is accomplished by an IPMulticastListen operation writing the first, second, third and fourth data into the first memory and wherein the accessing of the second, third and fourth data by the network interface is accomplished by the IPMulticastListen operation sending the second, third and fourth data to the network interface for storage in a second memory of the network interface. 
     
     
         10 . A method according to  claim 9 , wherein the IPMulticastListen operation writes the first, second, third and fourth data to the first memory and sends the second, third and fourth data to the network interface substantially simultaneously. 
     
     
         11 . A method according to  claim 1 , wherein the first, second, third and fourth data are stored as a first state record in the first memory, the first state record having the form (interface, multicast-address, filter-mode, {source-list}). 
     
     
         12 - 85 . (canceled) 
     
     
         86 . A method of filtering multicast data packets in a network interface situated between and coupled to a multicast data network and a bus of a computer system, the method comprising:
 the network interface storing information for the purpose of enabling or disabling the transmission of multicast packets from sources in the multicast data network through the network interface to the bus of the computer system, the information comprising first data that identifies a layer  2  multicast destination address and second data that identifies a layer  2  source address,   receiving in the network interface a multicast packet,   determining in the network interface the layer  2  destination address and the layer  2  source address of the multicast data packet,   determining in the network interface if transmission of the multicast packet from the network interface to the bus is to be enabled or disabled by comparing the layer  2  destination address and the layer  2  source address of the multicast packet with the first and second data; and   upon determining that the transmission of the multicast packet is to be enabled, the network interface transmitting the multicast packet to the bus, or upon determining that the transmission of the multicast packet is to be disabled, the network interface not transmitting the multicast packet to the bus.   
     
     
         87 . A method according to  claim 86 , wherein the multicast data network is an Ethernet network and the layer  2  destination address is a destination MAC address and the layer  2  source address is a Source MAC address. 
     
     
         88 . A method according to  claim 86 , wherein the network interface always transmits to the bus multicast packets having a first selected layer  2  destination address irregardless of the stored first and second data. 
     
     
         89 . A method according to  claim 88 , wherein a user application in an operating system of the computer system is used to select the first selected layer  2  destination address. 
     
     
         90 . A method according to  claim 86 , wherein the network interface never transmits to the bus multicast packets having a second selected layer  2  destination address irregardless of the stored first and second data. 
     
     
         91 . A method according to  claim 90 , wherein a user application in an operating system of the computer system is used to select the second selected layer  2  destination address. 
     
     
         92 . A method according to  claim 88 , wherein the network interface is configured to always transmits to the bus multicast packets having the first selected layer  2  destination address by use of the Simple Network Management Protocol (SNMP). 
     
     
         93 . A method according to  claim 90 , wherein the network interface is configured to never transmits to the bus multicast packets having the second selected layer  2  destination address by use of the Simple Network Management Protocol (SNMP). 
     
     
         94 . A method according to  claim 86 , wherein the filtering of multicast packets in the network interface is enabled or disabled by the use of a user application of an operating system of the computer system. 
     
     
         95 - 116 . (canceled)