Point-to-multipoint layer-2 network extension over layer-3 network

Patent metadata

Field	Value
Publication number	US-12047277-B2
Application number	US-202217932960-A
Country	US
Kind code	B2
Filing date	Sep 16, 2022
Priority date	Jun 24, 2020
Publication date	Jul 23, 2024
Grant date	Jul 23, 2024

Abstract

Techniques are disclosed for session-based routing of multipoint Open Systems Interconnection (OSI) Model Layer-2 (L2) frames of an L2 network extended over Layer-3 (L3) networks. In one example, L2 networks connect a source device to an ingress router and receiver devices to egress routers. An L3 network connects the ingress and egress routers. The ingress router receives, from the source device, a multipoint L2 frame destined for the receiver devices. The ingress router forms, for each egress router that is connected to at least one multipoint receiver device, a unicast L3 packet for the L2 frame and forwards the unicast L3 packet to the egress router. Each egress router generates, in response to receiving the unicast L3 packet, the multipoint L2 frame and forwards, to the receiver devices, the multipoint L2 frame.

First claim

What is claimed is:

1. A method comprising:
receiving, by an ingress router of a plurality of routers via a first Open Systems Interconnection (OSI) Model Layer-2 (L2) network, a multipoint L2 frame specifying receiver devices, wherein the plurality of routers form an OSI Model Layer-3 (L3) network;
determining, by the ingress router and based at least in part on the receiver devices specified by the multipoint L2 frame, one or more egress routers of the plurality of routers that are connected to at least one of the receiver devices via one or more second L2 networks;
determining, by the ingress router and based on the determined one or more egress routers, one or more paths from the ingress router to the determined one or more egress routers;
generating, by the ingress router and for each egress router of the determined one or more egress routers, a respective unicast L3 packet comprising:
an L3 header specifying a source address that is an address of the ingress router and a destination address that is an address of an intermediate router of the plurality of routers, the intermediate router being a next router along a path of the one or more paths toward the respective egress router of the determined one or more egress routers; and
a session identifier for the unicast L3 packet, the session identifier identifying a corresponding session between the ingress router and the respective egress router of the determined one or more egress routers; and

forwarding, by the ingress router, the respective unicast L3 packet for each egress router of the determined one or more egress routers.

2. The method of claim 1 ,
wherein the multipoint L2 frame comprises a Media Access Control (MAC) address for an unknown receiver device of the receiver devices,
wherein determining the one or more egress routers of the plurality of routers that are connected to at least one of the receiver devices comprises performing MAC learning to learn the MAC address for the unknown receiver device of the receiver devices, and
wherein the method further comprises storing, by the ingress router, the MAC address for the unknown receiver device.

3. The method of claim 1 , wherein each respective unicast L3 packet further comprises:
a first portion of metadata comprising a source Media Access Control (MAC) address of a source device originating the multipoint L2 frame and a multipoint destination MAC address of the receiver devices;
a second portion of metadata comprising the session identifier for the respective unicast L3 packet; and
an L3 payload comprising an L2 payload of the multipoint L2 frame.

4. The method of claim 1 ,
wherein the session identifier for the unicast L3 packet comprises a placeholder session identifier for the multipoint L2 frame, wherein the placeholder session identifier comprises a 5-tuple specifying placeholder L3 address information, and
wherein each respective unicast L3 packet further comprises an L3 payload comprising an L2 payload of the multipoint L2 frame.

5. The method of claim 1 ,
wherein determining the one or more egress routers of the plurality of routers that are connected to at least one of the receiver devices comprises determining that a first egress router of the plurality of routers is connected to two or more first receiver devices of the receiver devices and a second egress router of the plurality of routers is connected to two or more second receiver devices of the receiver devices,
wherein generating the respective unicast L3 packet comprises generating, for the first egress router, a respective first unicast L3 packet and generating, for the second egress router, a respective second unicast L3 packet, and
wherein forwarding the respective unicast L3 packet comprises forwarding the first unicast L3 packet toward the first egress router and forwarding the second unicast L3 packet toward the second egress router.

6. The method of claim 1 ,
wherein determining the one or more egress routers of the plurality of routers that are connected to at least one of the receiver devices comprises determining that each of a first egress router and a second egress router of the plurality of routers are connected to at least one of the receiver devices;
wherein generating the respective unicast L3 packet comprises:
generating, for the first egress router, a first unicast L3 packet comprising:
a first L3 header; and
a first session identifier identifying a first session between the ingress router and the first egress router; and

generating, for the second egress router, a second unicast L3 packet comprising:
a second L3 header; and
a second session identifier identifying a second session between the ingress router and the second egress router; and

wherein the forwarding comprises:
forwarding the first unicast L3 packet toward the first egress router; and
forwarding the second unicast L3 packet toward the second egress router.

7. The method of claim 1 ,
wherein the multipoint L2 frame comprises a multipoint Ethernet frame, and
wherein the respective unicast L3 packet for each egress router of the determined one or more egress routers comprises one of a unicast User Datagram Protocol (UDP) packet or a unicast Transmission Control Protocol (TCP) packet.

8. The method of claim 1 , wherein the multipoint L2 frame comprises a multicast Ethernet frame.

9. The method of claim 1 , wherein the multipoint L2 frame comprises a broadcast Ethernet frame.

10. The method of claim 1 , wherein the multipoint L2 frame comprises an unknown unicast Ethernet frame.

11. An ingress router configured to:
receive, via a first Open Systems Interconnection (OSI) Model Layer-2 (L2) network, a multipoint L2 frame specifying receiver devices, wherein a plurality of routers include the ingress router, and wherein the plurality of routers form an OSI Model Layer-3 (L3) network;
determine, based at least in part on the receiver devices specified by the multipoint L2 frame, one or more egress routers of the plurality of routers that are connected to at least one of the receiver devices via one or more second L2 networks;
determine, based on the determined one or more egress routers, one or more paths from the ingress router to the determined one or more egress routers;
generate, for each egress router of the determined one or more egress routers, a respective unicast L3 packet comprising:
an L3 header specifying a source address that is an address of the ingress router and a destination address that is an address of an intermediate router of the plurality of routers, the intermediate router being a next router along a path of the one or more paths toward the respective egress router of the determined one or more egress routers; and
a session identifier for the unicast L3 packet, the session identifier identifying a corresponding session between the ingress router and the respective egress router of the determined one or more egress routers; and

forward the respective unicast L3 packet for each egress router of the determined one or more egress routers.

12. The ingress router of claim 11 ,
wherein the multipoint L2 frame comprises a Media Access Control (MAC) address for an unknown receiver device of the receiver devices,
wherein to determine the one or more egress routers of the plurality of routers that are connected to at least one of the receiver devices, the ingress router is configured to perform MAC learning to learn the MAC address for the unknown receiver device of the receiver devices, and
wherein the ingress router is further configured to store the MAC address for the unknown receiver device.

13. The ingress router of claim

Assignees

• Juniper Networks Inc

Inventors

• Menon Abilash
• Yungelson Anna
• Mcculley Scott A
• Dionne Jacob

Classifications

• H04L45/745

  Address table lookup; Address filtering · CPC title

• H04L45/24 Primary

  Multipath · CPC title

• H04L12/46 Primary

  Interconnection of networks · CPC title

• H04L2101/622

  Layer-2 addresses, e.g. medium access control [MAC] addresses · CPC title

• H04L61/103

  across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP] · CPC title