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

Patent metadata

Field	Value
Publication number	US-12052163-B2
Application number	US-202117357743-A
Country	US
Kind code	B2
Filing date	Jun 24, 2021
Priority date	Jun 24, 2020
Publication date	Jul 30, 2024
Grant date	Jul 30, 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 and from a source device connected to the ingress router via a first Open Systems Interconnection (OSI) Model Layer-2 (L2) network, a multipoint L2 frame destined for one or more receiver devices, the multipoint L2 frame comprising an L2 header and an L2 payload, wherein the plurality of routers form an OSI Model Layer-3 (L3) network;
determining, by the ingress router and based on the L2 header of the multipoint L2 frame, one or more egress routers of the plurality of routers that are connected to the one or more receiver devices via one or more second L2 networks;
generating, by the ingress router, for each egress router of the determined one or more egress routers that are connected to the one or more receiver devices, and based at least in part on the received multipoint L2 frame, a unicast L3 packet comprising:
an L3 header specifying a source Internet Protocol (IP) address of the ingress router, a source port of the ingress router, a destination IP address of a next-hop peer router of the plurality of routers that is a next hop toward the respective egress router of the determined one or more egress routers, and a destination port of the next-hop peer router;
a session identifier for the unicast L3 packet, the session identifier identifying a session between the ingress router and the respective egress router of the determined one or more egress routers; and
an L3 payload; and

forwarding, by the ingress router, for each egress router of the determined one or more egress routers that are connected to the one or more receiver devices, and to the corresponding next-hop peer router of the plurality of routers, the generated unicast L3 packet corresponding to the respective egress router.

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

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

4. The method of claim 1 ,
wherein the multipoint L2 frame comprises a Media Access Control (MAC) address for an unknown receiver device of the one or more receiver devices,
wherein determining the one or more egress routers of the plurality of routers that are connected to the one or more receiver devices via one or more second L2 networks comprises selecting each router of the plurality of routers,
wherein generating, for each egress router of the determined one or more egress routers that are connected to the one or more receiver devices, the unicast L3 packet comprises generating, for each router of the plurality of routers, the unicast L3 packet, and
wherein forwarding, for each egress router of the determined one or more egress routers that are connected to the one or more receiver devices, and to the corresponding next-hop peer router of the plurality of routers, the generated unicast L3 packet corresponding to the respective egress router comprises forwarding, for each egress router of the determined one or more egress routers, and to the corresponding next-hop peer router of the plurality of routers, the generated unicast L3 packet corresponding to the respective egress router.

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

6. The method of claim 5 , wherein performing MAC learning to learn the MAC address for the unknown receiver device of the one or more receiver devices comprises:
generating, by the ingress router, a second unicast L3 packet encapsulating a first L2 packet comprising an Address Resolution Protocol (ARP) request; and
receiving, by the ingress router, a third unicast L3 packet encapsulating a second L2 packet comprising a response to the ARP request, the response comprising the MAC address for the receiver device of the one or more receiver devices.

7. The method of claim 1 ,
wherein the unicast L3 packet further comprises a first portion of metadata and a second portion of metadata,
wherein the first portion of metadata comprises a source Media Access Control (MAC) address of the source device and a multipoint destination MAC address of the one or more receiver devices,
wherein the second portion of metadata comprises the session identifier, and
wherein the L3 payload comprises the L2 payload.

8. 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 placeholder source IP address, a placeholder source port, a placeholder destination IP address, a placeholder destination port, and a placeholder network protocol, and
wherein the L3 payload of the unicast L3 packet comprises the multipoint L2 frame.

9. The method of claim 1 ,
wherein the one or more receiver devices comprise a first receiver device and a second receiver device,
wherein determining the one or more egress routers of the plurality of routers that are connected to the one or more receiver devices via one or more second L2 networks comprises:
determining a first egress router of the plurality of routers that is connected to the first receiver device via the one or more L2 networks; and
determining a second egress router of the plurality of routers that is connected to the first receiver device via the one or more L2 networks, and

wherein generating, for each egress router of the determined one or more egress routers that are connected to the one or more receiver devices, a unicast L3 packet comprises generating a first unicast L3 packet and a second unicast L3 packet, and
wherein forwarding the generated unicast L3 packet comprises:
forwarding, to a first next-hop peer router for the first egress router, the first L3 packet; and
forwarding, to a second next-hop peer router for the second egress router, the second L3 packet.

10. An ingress router of a plurality of routers, the ingress router comprising processing circuitry configured to:
receive, from a source device connected to the ingress router via a first Open Systems Interconnection (OSI) Model Layer-2 (L2) network, a multipoint L2 frame destined for one or more receiver devices, the multipoint L2 frame comprising an L2 header and an L2 payload, wherein the plurality of routers form an OSI Model Layer-3 (L3) network;
determine, based on the L2 header of the multipoint L2 frame, one or more egress routers of the plurality of routers that are connected to the one or more receiver devices via one or more second L2 networks;
generate, for each egress router of the determined one or more egress routers that are connected to the one or more receiver devices and based at least in part on the received multipoint L2 frame, a unicast L3 packet comprising:
an L3 header specifying a source Internet Protocol (IP) address of the ingress router, a source port of the ingress router, a destination IP address of a next-hop peer router of the plurality of routers that is a next hop toward the respective egress router of the determined one or more egress routers, and a destination port of the next-hop peer router;
a session identifier for the unicast L3 packet, the session identifier identifying a s

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