Optimal multicast forwarding for sources behind EVPN fabric

Patent metadata

Field	Value
Publication number	US-12549401-B2
Application number	US-202318317895-A
Country	US
Kind code	B2
Filing date	May 15, 2023
Priority date	Dec 7, 2022
Publication date	Feb 10, 2026
Grant date	Feb 10, 2026

Abstract

A system and associated methods provide procedures for establishing multicast connections and forwarding multicast content from a source to a subscriber when an ingress provider edge in communication with the subscriber is connected to an egress provider edge device belonging to an EVPN instance, especially in cases where the egress provider edge device is not receiving content from the source. The system configures “backup” provider edge devices belonging to the EVPN instance to temporarily forward the multicast content to the egress provider edge device on behalf of the source, enabling the ingress provider edge device and subscriber to continue to receive the multicast content from the source while the multicast network adjusts to recognize a new egress provider edge device. Methods of establishing connections between the ingress provider edge device and the correct egress provider edge device are also provided to avoid flooding and inefficient content forwarding throughout the network.

First claim

What is claimed is:

1 . A method, comprising:
sending, by an egress provider edge device of a plurality of provider edge devices of an Ethernet Virtual Private Network (EVPN) instance, a source announcement to a first backup provider edge device of the EVPN instance and to an ingress provider edge device, wherein the source announcement includes Virtual Routing and Forwarding for Internet Protocol (IP-VRF) Extended Community (EC) information and Virtual Routing and Forwarding for Media Access Control (MAC-VRF) EC information; the egress provider edge device being in communication with a source operable for sending multicast content; and the ingress provider edge device being in communication with a subscriber requesting multicast content from the source; establishing a reverse path forwarding tunnel between the ingress provider edge device and the egress provider edge device using the IP-VRF EC information; establishing a unicast tunnel between the first backup provider edge device and the egress provider edge device using the MAC-VRF EC information; receiving, at the first backup provider edge device, multicast content from the source; and forwarding, at the first backup provider edge device and over the unicast tunnel between the first backup provider edge device and the egress provider edge device, multicast content from the source to the egress provider edge device.

2 . The method of claim 1 , further comprising:
forwarding, by the ingress provider edge device, multicast content from the egress provider edge device to the subscriber.

3 . The method of claim 1 , further comprising:
sending, by the ingress provider edge device in communication with the subscriber requesting content from the source over the multicast network, a join request message to the plurality of provider edge devices of the EVPN instance; and designating a first provider edge device of the plurality of provider edge devices of the EVPN instance as the egress provider edge device.

4 . The method of claim 1 , further comprising:
advertising, by the plurality of provider edge devices of the EVPN instance and to the ingress provider edge device, a Unicast Prefix Advertisement that includes information about a location of respective provider edge devices of the EVPN instance; the Unicast Prefix Advertisement further including Extended Community (EC) information indicative of the EVPN instance.

5 . The method of claim 1 , further comprising:
designating the first backup provider edge device as a new egress provider edge device, the new egress provider edge device being in communication with the source; establishing a reverse path forwarding tunnel between the new egress provider edge device and the ingress provider edge device; and forwarding, by the new egress provider edge device, multicast content from the source to the ingress provider edge device.

6 . The method of claim 5 , further comprising:
establishing a unicast tunnel between a second backup provider edge device of the EVPN instance and the new egress provider edge device, the second backup provider edge device of the EVPN instance being operable for receiving multicast content from the source and forwarding the multicast content to the new egress provider edge device.

7 . The method of claim 1 , wherein the sending of the source announcement occurs after the ingress provider edge device sends a join request message to the plurality of provider edge devices of the EVPN instance, and wherein no reverse path forwarding tunnel is established at the time the join request message is sent.

8 . The method of claim 1 , wherein after receiving a join request message from the ingress provider edge device and before receiving the source announcement, a Multicast Routing Information Base (MRIB) state of the egress provider edge device and the first backup provider edge device includes an incoming interface set to an Integrated Routing and Bridging (IRB) interface.

9 . The method of claim 1 , wherein the unicast tunnel established between the first backup provider edge device and the egress provider edge device is a Broadcast, unknown-unicast and multicast (BUM) tunnel.

10 . The method of claim 1 , wherein the receiving and forwarding steps performed by the first backup provider edge device occur in response to the source ceasing communication with the egress provider edge device and initiating communication with the first backup provider edge device due to a source move or an Ethernet segment failure.

11 . A system, comprising:
one or more processors in communication with one or more memories, the one or more memories including instructions executable by the one or more processors to:
send, by an egress provider edge device of a plurality of provider edge devices of an Ethernet Virtual Private Network (EVPN) instance, a source announcement to a first backup provider edge device of the EVPN instance and to an ingress provider edge device, wherein the source announcement includes Virtual Routing and Forwarding for Internet Protocol (IP-VRF) Extended Community (EC) information and Virtual Routing and Forwarding for Media Access Control (MAC-VRF) EC information;
the egress provider edge device being in communication with a source operable for sending multicast content; and
the ingress provider edge device being in communication with a subscriber requesting multicast content from the source;
establishing a reverse path forwarding tunnel between the ingress provider edge device and the egress provider edge device using the IP-VRF EC information;
establish a unicast tunnel between the first backup provider edge device and the egress provider edge device using the MAC-VRF EC information;
receive, at the first backup provider edge device, multicast content from the source; and
forward, at the first backup provider edge device and over the unicast tunnel between the first backup provider edge device and the egress provider edge device, multicast content from the source to the egress provider edge device.

12 . The system of claim 11 , the one or more memories further including instructions executable by the one or more processors to:
forward, by the ingress provider edge device, multicast content from the egress provider edge device to the subscriber.

13 . The system of claim 11 , the one or more memories further including instructions executable by the one or more processors to:
send, by the ingress provider edge device in communication with the subscriber requesting content from the source over the multicast network, a join request message to the plurality of provider edge devices of the EVPN instance; and designate a first provider edge device of the plurality of provider edge devices of the EVPN instance as the egress provider edge device.

14 . The system of claim 11 , the one or more memories further including instructions executable by the one or more processors to:
designate the first backup provider edge device as a new egress provider edge device, the new egress provider edge device being in communication with the source;
establish a reverse path forwarding tunnel between the new egress provider edge device and the ingress provider edge device;
establish a unicast tunnel between a second backup provider edge device of the EVPN instance and the new egress provider edge device, the second backup provider edge device of the EVPN instance being operable for receiving multicast content from the source and forwarding the multicast content to the new egress provider edge device; and
forward, by the new egress provider edge device, multicast content from the so

Assignees

• Cisco Tech Inc

Inventors

• Mishra Mankamana Prasad
• Gulrajani Sameer R
• Sajassi Ali
• Agrawal Swadesh
• Kumar Nitin

Classifications

• H04L12/4633 Primary

  Interconnection of networks using encapsulation techniques, e.g. tunneling · CPC title

• H04L12/1886

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

• H04L12/185 Primary

  with management of multicast group membership · CPC title

• H04L12/4641

  Virtual LANs, VLANs, e.g. virtual private networks [VPN] (LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272) · CPC title

• H04L45/16

  Multipoint routing · CPC title