Patent ID: 7697524
Filing Date: 2010-04-13
Classification: H04L

Abstract:
1. A method for determining a path maximum transmission unit (PMTU) for an internet protocol (IP) multicast, the method comprising: transferring packets from a source device to a plurality of destination devices in a network using the IP multicast, wherein a rate for message generation returned from intermediate nodes coupled between the source device and at least one of the plurality of destination devices is controlled, wherein a first of the intermediate nodes is in a first path of the IP multicast to at least one of the plurality of destination devices, and wherein a second of the intermediate nodes is in a second path of the IP multicast to at least one of the plurality of destination devices; receiving a message in the source device, the message being sent from the first intermediate node and at less than or equal to the controlled rate, and in response to a packet transmitted from the source device and received in the first intermediate node having a size greater than a maximum transmission unit (MTU) of a link in the first path and a don't fragment (DF) bit being set in the packet, the DF bit being set by the source device, the link comprising a connection to the first intermediate node in the first path of the IP multicast, wherein a corresponding generation of the message is suppressed and the packet is dropped in the second path by the second intermediate node; and determining the PMTU of a multicast distribution tree for the IP multicast, the multicast distribution tree comprising a set of paths from the source device to the plurality of destination devices and along which the packet is delivered to the plurality of destination devices, the set of paths comprising the first and second paths.