Granted Patent B2

US 7,742,457 · App. 11/427,720 · Granted Jun 22, 2010

Abstract

Claims (44)

1. A digital home communication terminal (DHCT) for reducing multicast IP packet bandwidth in a local area network carrying Internet protocol television (IPTV) traffic, the DHCT comprising:

logic for determining an IP multicast address and a port identifier, each associated with a slave DHCT;

logic for transmitting a layer-2 multicast address derived from the IP multicast address and the port identifier to the switch as a request for the switch to operate in a first multicast configuration,

the layer-2 switch operating in the first multicast configuration to associate the first layer-2 multicast address with the data port, examine layer-2 packets having a layer-2 multicast destination address, and forward the examined layer-2 multicast packets on the data port, wherein the forwarding occurs only if the layer-2 destination address is the first layer-2 multicast address.

2. The DHCT of claim 1 , wherein the DHCT further comprises:

logic to receive a configuration request from the slave DHCT, the configuration request including an IP multicast address and a port identifier; and

logic to map the IP multicast address to the layer-2 multicast address,

wherein the logic for requesting further comprises logic to transmit the layer-2 multicast address and the identified port to the switch as a request to operate in the first configuration.

3. The DHCT of claim 1 , wherein the DHCT further comprises:

logic to receive an IGMP join request for an IP multicast address;

logic to map the IP multicast address to the layer-2 multicast address; and

logic to identify which of the plurality of data ports the IGMP join request was transmitted from,

wherein the logic for requesting further comprises logic to transmit the layer-2 multicast address and the identified port to the switch as a request to operate in the first configuration.

4. The DHCT of claim 1 , wherein the DHCT further comprises:

logic to receive an IGMP leave request for the IP multicast address;

wherein the logic for requesting further comprises logic to transmit the layer-2 multicast address and the identified port to the switch as a request to operate in a second configuration,

wherein while in the second configuration the layer-2 switch forwards layer-2 multicast packets onto the first data port even if the layer-2 destination address of the received packets is not the first layer-2 multicast address.

5. The DHCT of claim 1 , wherein the DHCT further comprises:

logic to receive packets addressed to a first IP multicast address associated with advertisement of IPTV services;

logic to extract a second IP multicast address from one of the packets; and

logic to receive the IGMP join request on the second IP multicast address.

6. The DHCT of claim 1 , wherein the DHCT further comprises:

logic for requesting the layer-2 switch, over the control channel, to operate in a second configuration wherein the layer-2 switch forwards layer-2 multicast packets onto the first data port even if the layer-2 destination address is not the first layer-2 multicast address.

7. The DHCT of claim 1 , wherein the switch comprises:

a forwarding engine;

a multicast egress filter associated with a filter multicast address and a block behavior, the block behavior associated with an egress port; and

configuration logic configured to associate a specified layer-2 multicast address, received via the control channel, with the multicast egress filter and to associate a specified port and behavior, received via the control channel, with the multicast egress filter,

wherein the forwarding engine compares a received multicast packet against the filter multicast address and forwards the multicast packet on the egress port only if the port behavior specifies blocking.

8. A method, performed in a digital home communication terminal (DHCT), for reducing multicast IP packet bandwidth in a local area network carrying Internet protocol television (IPTV) traffic, the method comprising:

determining an IP multicast address and a port identifier, each associated with a slave DHCT;

mapping the IP multicast address to a layer-2 multicast address; and

requesting the layer-2 switch, over the control channel, to operate in a first multicast configuration,

the layer-2 switch operating in the first multicast configuration to associate the first layer-2 multicast address with the identified port, examine layer-2 packets having a layer-2 multicast destination address, and forward the examined layer-2 multicast packets on the identified port, wherein the forwarding occurs only if the layer-2 destination address matches the first layer-2 multicast address.

9. The method of claim 8 , wherein the port identifier comprises an Ethernet unicast address assigned to the slave DHCT or a port number identifying a data port on the switch to which the slave DHCT is coupled.

10. The method of claim 8 , wherein the determining step further comprises:

receiving a configuration request from the slave DHCT, the configuration request including the IP multicast address and the port identifier.

11. The method of claim 8 , wherein the determining step further comprises:

receiving an IGMP join request for the IP multicast address; and

identifying which of the plurality of data ports the IGMP join request was transmitted from,

wherein the requesting step further comprises transmitting the layer-2 multicast address and the identified port to the switch as a request to operate in the first configuration.

12. The method of claim 8 , further comprising:

receiving an IGMP leave request for the IP multicast address;

wherein the requesting step further comprises transmitting the layer-2 multicast address and the identified port to the switch as a request to operate in a second configuration,

wherein while in the second configuration the layer-2 switch forwards layer-2 multicast packets onto the first data port even if the layer-2 destination address of the received packets is not the first layer-2 multicast address.

Assignments (9)