# US 12,192,086 B2 · Validating reachability for liaison VRFs using OAM ping packets

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- Number: US 12,192,086 B2
- Document ID: US12192086B2
- Status: Granted
- Kind: B2
- Application number: 17/728,395
- Filed: 2022-04-25
- Published: 2023-10-26
- Granted: 2025-01-07
- Earliest claimed: 2022-04-25
- Assignees: Hewlett Packard Enterprise Development LP
- Applicants: Hewlett Packard Enterprise Development LP
- Inventors: Saumya Dikshit; Ashwini Dahiya; Srinath Krishna Rao
- Web page: https://patentgrep.com/patent/US12192086B2

## CPC

- H04L 43/10: Active monitoring, e.g. heartbeat, ping or trace-route
- H04L 12/4633: {Interconnection of networks using encapsulation techniques, e.g. tunneling}
- H04L 12/4641: {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)}
- H04L 43/0811: by checking connectivity
- H04L 43/20: the monitoring system or the monitored elements being virtualised, abstracted or software-defined entities, e.g. SDN or NFV
- H04L 45/02: Topology update or discovery
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Systems and methods provide a new type of time-length-value data stream (TLV) which can be encapsulated in an OAM ping packet. This “EVI TLV” encapsulating OAM ping packet can be sent to a network device (e.g., a border router) that a liaison VRF is provisioned on. Upon receipt, the encapsulated EVI TLV instructs the network device to determine whether the configuration of the liaison VRF is mapped to an EVI value specified by the EVI TLV. If the configuration of the liaison VRF is mapped to the specified EVI value, the network device returns an echo response indicating that the configuration of the liaison VRF is mapped onto the specified EVI value. Such a response may indicate that the liaison VRF is reachable for the EVPN.

## Claims

### Claim 1

A method comprising:
sending, by a first device, to a second device in a Virtual Private Network (VPN), an Operations, Administration, and Maintenance (OAM) ping packet, wherein;
a liaison Virtual Routing and Forwarding instance (VRF) is provisioned on the second device,
the liaison VRF functions to publish learned external routes to other devices within the VPN,
the OAM ping packet encapsulates a VPN Instance Identifier (EVI) time-length-value data stream (TLV) (collectively an EVI TLV), and
the EVI TLV specifies an EVI value; and
receiving, by the first device, from the second device, a response to the OAM ping packet indicating that a configuration of the liaison VRF is mapped onto the specified EVI value.

### Claim 2 (depends on 1)

The method of claim 1, further comprising, determining, by the first device, that the liaison VRF is reachable within the VPN.

### Claim 3 (depends on 1)

The method of claim 1, wherein the liaison VRF has not published any learned external routes to the other devices within the VPN.

### Claim 4 (depends on 1)

The method of claim 1, wherein the VPN comprises an Ethernet VPN (EVPN).

### Claim 5 (depends on 4)

The method of claim 4, wherein the EVPN comprises a Vxlan data plane and the EVI value comprises a Virtual Network Identifier (VNI) associated with the Vxlan data plane.

### Claim 6 (depends on 4)

The method of claim 4, wherein the EVPN comprises an MPLS data plane and the EVI value comprises an identifying label associated with the MPLS data plane.

### Claim 7 (depends on 4)

The method of claim 4, wherein the second device comprises a border router of the EVPN.

### Claim 8 (depends on 1)

The method of claim 1, wherein the first device is a device within the VPN.

### Claim 9

A first device in an EVPN, the first network device comprising:
a plurality of processing resources associated with the first device; and
a non-transitory computer-readable medium, coupled to the plurality of processing resources, having stored therein instructions that when executed by the processing resources cause the first device to:
receive, from a second device, an OAM ping packet, wherein;
a liaison VRF is provisioned on the first device,
the liaison VRF functions to publish learned external routes to other devices within the EVPN,
the OAM ping packet encapsulates an EVI TLV, and
the EVI TLV specifies an EVI value;
determine that a configuration of the liaison VRF is mapped onto the specified EVI value; and
send, to the second device, a response to the OAM ping packet indicating that the configuration of the liaison VRF is mapped onto the specified EVI value.

### Claim 10 (depends on 9)

The first device of claim 9, wherein the response to the OAM ping packet comprises an echo response.

### Claim 11 (depends on 9)

The first device of claim 9, wherein the response to the OAM ping packet also indicates that the liaison VRF is reachable within the EVPN.

### Claim 12 (depends on 9)

The first device of claim 9, wherein the first device comprises a border router of the EVPN.

### Claim 13 (depends on 9)

The first device of claim 9, wherein the liaison VRF has not published any learned external routes to the other devices within the EVPN.

### Claim 14 (depends on 9)

The first device of claim 9, wherein the EVPN comprises a Vxlan data plane and the EVI value comprises a VNI associated with the Vxlan data plane.

### Claim 15 (depends on 9)

The first device of claim 9, wherein the EVPN comprises an MPLS data plane and the EVI value comprises an identifying label associated with the MPLS data plane.

### Claim 16 (depends on 9)

The first device of claim 9, wherein the second device is a device within the EVPN.

### Claim 17

A non-transitory computer-readable medium storing instructions, which when executed by a plurality of processing resources of a first device, cause the first device to:
send, to a second device in an EVPN, an OAM ping packet, wherein;
a liaison VRF is provisioned on the second device,
the liaison VRF functions to publish learned external routes to other devices within the EVPN,
the OAM ping packet encapsulates an EVI TLV, and
the EVI TLV specifies an EVI value;
receive, from the second device, a response to the OAM ping packet indicating that a configuration of the liaison VRF is mapped onto the specified EVI value; and
determining the liaison VRF is reachable within the EVPN.

### Claim 18 (depends on 17)

The non-transitory computer-readable medium of claim 17, wherein the liaison VRF has not published any learned external routes to other devices within the EVPN.

### Claim 19 (depends on 17)

The non-transitory computer-readable medium of claim 17, wherein EVPN comprises a Vxlan data plane and the EVI value comprises a VNI associated with the Vxlan data plane.

### Claim 20 (depends on 17)

The non-transitory computer-readable medium of claim 17, wherein the EVPN comprises an MPLS data plane and the EVI value comprises an identifying label associated with the MPLS data plane.