Multicast forwarding method and multicast router

Patent metadata

Field	Value
Publication number	US-11190367-B2
Application number	US-202016830864-A
Country	US
Kind code	B2
Filing date	Mar 26, 2020
Priority date	Sep 27, 2017
Publication date	Nov 30, 2021
Grant date	Nov 30, 2021

Abstract

This application discloses a multicast forwarding method and a multicast router. The method includes: listening to, by a first multicast router, a plurality of unicast packets passing through the first multicast router, and determining a set of unicast packets that are from a same upstream multicast router and that belong to a same unicast stream; when determining that destination addresses of at least two unicast packets in the unicast packet set are different, sending, by the first multicast router, a prune message to the upstream multicast router; and sending, by the first multicast router, the received unicast packets with the multicast identifier to the destination devices corresponding to the destination address group. The method is used to provide a new multicast method, so as to implement multicast functions of some routers in an existing unicast network architecture.

First claim

What is claimed is:

1. A multicast forwarding method comprising:
listening to, by a first multicast router, a plurality of unicast packets passing through the first multicast router;
determining a set of unicast packets that are from a same upstream multicast router and that belong to a same unicast stream, wherein the unicast packets in the unicast stream carry a same multicast identifier, and the multicast identifier indicates that the unicast packets in the unicast stream are from a same data source server and are to be sent to destination devices that belong to a same multicast group;
when determining that destination addresses of at least two unicast packets in the unicast packet set are different, sending, by the first multicast router, a prune message to the upstream multicast router, wherein the prune message carries a destination address group determined from all the unicast packets in the unicast packet set, the prune message used to instruct the upstream multicast router to stop sending the unicast packets with the multicast identifier to the destination devices corresponding to the destination address group, and send the to-be-sent unicast packets with the multicast identifier to the first multicast router; and
sending, by the first multicast router, the received unicast packets with the multicast identifier to the destination devices corresponding to the destination address group.

2. The method according to claim 1 , wherein the method further comprises:
when determining that destination addresses of at least two unicast packets in the unicast packet set are different, obtaining, by the first multicast router, destination addresses of all packets in the unicast packet set, and generating a first multicast routing entry, wherein a source address of the first multicast routing entry is an address of the first multicast router, and the destination address group comprises all the destination addresses; and
the sending, by the first multicast router, the received unicast packets with the multicast identifier to the destination devices corresponding to the destination address group comprises:
modifying, by the first multicast router, the received unicast packet with the multicast identifier based on the first multicast routing entry, to obtain a modified unicast packet, wherein a source address of the modified unicast packet is the address of the first multicast router, and a destination address of the modified unicast packet is a destination address in the destination address group and in the first multicast routing entry; and
sending, by the first multicast router, the modified unicast packet to the destination devices corresponding to the destination address group.

3. The method according to claim 2 , further comprising:
obtaining, by the first multicast router through listening, a first message sent by the upstream multicast router, wherein the first message carries the multicast identifier and a first target address, and is used to indicate that a destination device corresponding to the first target address stops receiving a unicast packet with the multicast identifier;
searching, by the first multicast router, for the first multicast routing entry corresponding to the multicast identifier, and determining that the first target address belongs to the destination address group; and
removing, by the first multicast router, the first target address from the first multicast routing entry, and stopping sending the unicast packet with the multicast identifier to the destination device corresponding to the first target address.

4. The method according to claim 3 , further comprising:
determining, by the first multicast router, that a destination address in the first multicast routing entry from which the first target address is removed is empty; and
instructing, by the first multicast router, the upstream multicast router to stop sending the unicast packet with the multicast identifier to the first multicast router.

5. A multicast forwarding method comprising:
receiving, by a second multicast router, a prune message from a downstream multicast router, wherein the prune message comprises a destination address group determined by the downstream multicast router from all unicast packets in a unicast packet set, the unicast packet set is a set of unicast packets that are obtained by the downstream multicast router by listening to a plurality of unicast packets passing through the downstream multicast router that are from the second multicast router, and that belong to a same unicast stream, a unicast packet in the unicast stream carries a multicast identifier, and the multicast identifier indicates that the unicast packets in the unicast stream are from a same data source server and are to be sent to destination devices that belong to a same multicast group; and
stopping, by the second multicast router based on the prune message, sending the unicast packets with the multicast identifier to the destination devices corresponding to the destination address group, and sending the to-be-sent unicast packets with the multicast identifier to the downstream multicast router.

6. The method according to claim 5 , before the receiving, by a second multicast router, a prune message from a downstream multicast router, further comprising:
receiving, by the second multicast router, a registration request from the data source server, wherein the registration request carries IP four-tuple information of a User Datagram Protocol (UDP) session;
allocating, by the second multicast router, a multicast group identifier to the UDP session based on the registration request;
sending, by the second multicast router, a registration request response message to the data source server, wherein the response message carries the multicast group identifier; and
receiving, by the second multicast router, a unicast packet sent by the data source server, wherein a header of the unicast packet carries the multicast identifier, and the multicast identifier is generated by the data source server based on an address of the data source server and the multicast group identifier.

7. The method according to claim 6 , further comprising:
receiving, by the second multicast router, an on-demand request from a first client, wherein the on-demand request is used to request to subscribe to the UDP session; and
generating, by the second multicast router, a second multicast routing entry, wherein a source address of the second multicast routing entry is an address of the second multicast router, and a destination address of the second multicast routing entry is an address of the first client; and
the sending, by the second multicast router, a to-be-sent unicast packet with the multicast identifier to the downstream multicast router comprises:
modifying, by the second multicast router, the received unicast packet with the multicast identifier based on the second multicast routing entry, to obtain a modified unicast packet, wherein a source address of the modified unicast packet is the address of the second multicast router, and a destination address of the modified unicast packet is the address of the first client; and
sending, by the second multicast router, the modified unicast packet with the multicast identifier to the first client.

8. The method according to claim 7 , further comprising:
receiving, by the second multicast router, an on-demand stop request sent by the first client, wherein the on-demand stop request is used to request to stop subscribing to the UDP session;
searching, by the second multicast router, for the second multicast routing entry corresponding to the multicast identifier, and determining that the address of the first client is comprised in the destination ad

Assignees

• Huawei Tech Co Ltd

Inventors

• Meng Rui
• Wang Chuang
• Huang Yong

Classifications

• H04L12/18 Primary

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

• H04L45/745

  Address table lookup; Address filtering · CPC title

• H04L45/74

  Address processing for routing · CPC title

• H04L12/1886

  with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains · CPC title

• H04L45/16 Primary

  Multipoint routing · CPC title