Method for pruning a multicast branch, protocol independent multicast router, and layer-2 exchange

Patent metadata

Field	Value
Publication number	US-9497034-B2
Application number	US-201113876141-A
Country	US
Kind code	B2
Filing date	Sep 30, 2011
Priority date	Sep 30, 2010
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

According to an example, a multicast source may be connected to a first hop Protocol Independent Multicast (PIM) router via one or multiple layer-2 switches that has PIM functions. A first hop PIM router may receive a multicast flow initiated by the multicast source, send a PIM prune message via a port from which the multicast flow is received in response to a determination that the multicast flow is not to be received, or the first hop PIM router may receive a PIM prune message for a multicast flow from a downstream PIM router or a multicast group leave message for a multicast flow from a client connected to the first hop PIM router and delete a port via which the PIM prune message.

First claim

What is claimed is:

1. A layer-2 exchange with Protocol Independent Multicast (PIM) snooping functions, for deployment between a multicast source and a first hop PIM router, the layer-2 exchange comprising:
a processor; and
a memory storing instructions that when executed by the processor cause the processor to:
receive a PIM prune message for a multicast flow,
in response to a determination that an upstream neighbor address in the PIM prune message is not in a list of PIM routers maintained by the PIM snooping functions of the layer-2 exchange, add a port from which the PIM prune message is received into a list of egress ports in a PIM snooping entry corresponding to the multicast flow and mark the port in the list of egress ports as a prune port,
stop forwarding the multicast flow via the port that is marked as the prune port; and
set a lifetime value for the prune port smaller than the lifetime value of an entry of the multicast flow corresponding to the PIM prune message in the first hop PIM router; to set the prune port as a temporary router port when the lifetime value of the prune port expires, and to set the temporary router port as a router port if a PIM prune message for the multicast flow is not received within a pre-defined period of time; and to set the temporary router port as a prune port and reset the lifetime value of the prune port if a PIM prune message for the multicast flow is received within the pre-defined time period.

2. The exchange of claim 1 , wherein the processor is further to set a prune time for the prune port, and to begin forwarding the multicast flow to the prune port when the prune time expires.

3. The exchange of claim 1 , wherein, the processor is further to, in response to a determination that the upstream neighbor address in the PIM prune message is not in a list of PIM routers using PIM snooping functions of the exchange and a PIM snooping entry has not been established for the multicast flow in the exchange, establish a PIM snooping entry for the multicast flow, to set an empty list as an upstream neighbor list in the PIM snooping entry, to add all ports connected to PIM neighbors except upstream ports into a downstream egress port list in the PIM snooping entry, to perform the adding of the prune port into the PIM snooping entry corresponding to the multicast flow; and
to determine whether the multicast flow corresponding to the PIM prune message is to be forwarded based on PIM snooping entries and multicast group management entries in the layer-2 exchange, forwarding no PIM prune message if the multicast flow corresponding to the PIM prune message is to be forwarded, or forwarding the PIM prune message in the direction of the multicast source if the multicast flow corresponding to the PIM prune message is not to be forwarded.

4. The exchange of claim 1 , wherein the processor is further to directly perform the adding of the prune port into the PIM snooping entry corresponding to the multicast flow in response to a determination that an upstream neighbor address in the PIM prune message is not in a list of PIM routers using PIM snooping functions of the exchange and a PIM snooping entry has been established for the multicast flow in the exchange; and
to determine whether there the multicast flow corresponding to the PIM prune message is to be forwarded based on PIM snooping entries and multicast group management entries in the layer-2 exchange, forwarding no PIM prune message if the multicast flow corresponding to the PIM prune message is to be forwarded, or forwarding the PIM prune message in the direction of the multicast source if the multicast flow corresponding to the PIM prune message is not to be forwarded.

5. The exchange of claim 1 , wherein the processor is further to receive a PIM join message for a multicast flow; in response to a determination that the upstream neighbor address in the message is not in a list of PIM routers that are maintained by PIM snooping functions of the exchange, to determine whether there is another port other than the port from which the PIM join message is received is to receive the multicast flow based on PIM snooping entries and multicast group management snooping entries in the exchange in response to a determination that there is a PIM snooping entry for the multicast flow corresponding to the PIM join message in the exchange and the port receiving the PIM join message is a prune port in the PIM snooping entry, to forward no PIM join message when there is another port that is to receive the multicast flow, or to forward the PIM join message in the direction of the multicast source if there is no other port that is to receive the multicast flow.

6. The exchange of claim 5 , wherein the processor is further to delete a mark which labels the port from which the PIM join message is received as a prune port and to set the port as a router port, and to delete the PIM snooping entry corresponding to the multicast flow if the downstream egress port list of the PIM snooping entry does not include a prune port and the upstream neighbor list is empty.

7. The exchange of claim 1 , wherein the processor is further to receive a multicast group join message for a multicast flow, to add a port from which the multicast group join message is received into a multicast group management snooping entry corresponding to the multicast flow as a membership port, and to forward the multicast group join message to all router ports, prune ports and upstream neighbors in the PIM snooping entry except the port from which the multicast group join message is received.

8. A method for pruning a multicast branch in a network comprising a multicast source connected to a first hop PIM router via at least one layer-2 exchange with Protocol Independent Multicast (PIM) snooping functions, said method comprising:
receiving, by the first hop PIM router, a multicast flow initiated by the multicast source, sending a PIM prune message to the at least one layer-2 exchange via a port from which the multicast flow is received in response to a determination that the multicast flow is not to be received, and setting a lifetime value of an entry of the multicast flow corresponding to the PIM prune message in the first hop PIM router greater than a lifetime value for a prune port of the at least one layer-2 exchange; and
receiving, by the first hop PIM router, a PIM prune message for a multicast flow from a downstream PIM router or a multicast group leave message for a multicast flow from a client connected to the first hop PIM router, deleting a port via which the PIM prune message or the multicast group leave message is received from an egress port list corresponding to the multicast flow, and sending a PIM prune message addressed to the multicast source via the port from which the multicast flow is received in response to a determination that the multicast flow is not to be received.

9. The method of claim 8 , further comprising:
receiving, by one of the at least one layer-2 exchange, the PIM prune message from the first hop PIM router, adding a port from which the PIM prune message is received into a PIM snooping entry corresponding to the multicast flow, marking the added port as a prune port, and stopping forwarding of the multicast flow via the prune port.

10. A Protocol Independent Multicast (PIM) router, connected to a multicast source via at least one layer-2 exchange, comprising:
a processor; and
a memory storing instructions that when executed by the processor cause the processor to receive a multicast flow initiated by the multicast source, to determine whether the multicast flow is to be received, to send a prune indication to the at least one layer-2 exchange in response t

Assignees

• Zhou Di
• Liu Yu
• Chen Qianye
• Chen Xusheng
• Hewlett Packard Entpr Dev Lp

Inventors

• Zhou Di
• Liu Yu
• Chen Qianye
• Chen Xusheng

Classifications

• H04L45/16 Primary

  Multipoint routing · CPC title

• H04L12/18 Primary

  for broadcast or conference {, e.g. multicast} · CPC title

• H04L12/185 Primary

  with management of multicast group membership · CPC title

• H04L47/15

  in relation to multipoint traffic (arrangements for broadcast or multicast in data networks H04L12/18) · CPC title