Method and system for performing network fault analysis

1. A method comprising:

sending, by a host device initiating fault analysis, a query message through a tunnel interface present in an overlay network configured over an underlay network, wherein the query message determines connectivity to network devices present in the overlay network, and the underlay network provides a physical infrastructure supporting movement of data of the overlay network,

tracing, while an upstream interface is a network tunnel having a first end and a second end, a unicast path from the first end to the second end of the network tunnel, using a network route analysis function;

determining that a destination device present on the second end of the network tunnel is not reachable;

appending information present in a first data packet obtained as an output of a multicast network connectivity determining function and information present in a second data packet obtained as an output of the network route analysis function to produce an appended result; and

sending the appended result to the host device.

2. The method as claimed in claim 1 , wherein the network devices comprise switches and routers.

3. The method as claimed in claim 1 , wherein the query message is a User Datagram Protocol (UDP) packet.

4. The method as claimed in claim 1 , wherein the network tunnel utilizes at least one of Internet Protocol (IP) tunnelling, Generic Routing Encapsulation (GRE) tunnelling, OpenVPN tunnelling, Secure Socket Tunneling Protocol (SSTP), Internet Protocol Security (IPsec) tunnelling, Layer 2 Tunneling Protocol (L2TP), Virtual Extensible Local Area Network (VXLAN), Secure Shell (SSH) tunnelling, Hyper Text Transfer Protocol (HTTP) tunnelling, Internet Configuration Management Protocol (ICMP) tunnelling, General Packet Radio Service (GPRS) Tunnelling Protocol (GTP), Multiprotocol Label Switching (MPLS) tunnelling, and Virtual private network (VPN) tunnelling.

5. The method as claimed in claim 1 , wherein a network device present at the first end of the network tunnel appends the information present in the first data packet obtained as the output of the multicast network connectivity determining function and the information present in the second data packet obtained as the output of the network route analysis function.

6. The method as claimed in claim 1 , wherein an output of the network route analysis function includes details of the network devices with which communication could be established, and wherein the network devices are present in one or more network paths.

7. A network device comprising:

a processor; and

a memory storing programmed instructions, which when executed by the processor, causes the processor to:

send a query message through a tunnel interface present in an overlay network configured over an underlay network, wherein the query message determines connectivity to network devices present in the overlay network, and the underlay network provides a physical infrastructure supporting movement of data of the overlay network;

trace, while an upstream interface being a network tunnel having a first end and a second end, a unicast path from the first end to the second end of the network tunnel, using a network route analysis function;

determine that a destination device present on the second end of the network tunnel is not reachable;

append information present in a first data packet obtained as an output of a multicast network connectivity determining function and information present in a second data packet obtained as an output of the network route analysis function to produce an appended result; and

send the appended result to a host device that generated the query message.

8. The network device as claimed in claim 7 , wherein the network devices comprise switches and routers.

9. The network device as claimed in claim 7 , wherein the query message is a User Datagram Protocol (UDP) packet.

10. The network device as claimed in claim 7 , wherein the network tunnel utilizes at least one of Internet Protocol (IP) tunnelling, Generic Routing Encapsulation (GRE) tunnelling, OpenVPN tunnelling, Secure Socket Tunneling Protocol (SSTP), Internet Protocol Security (IPsec) tunnelling, Layer 2 Tunneling Protocol (L2TP), Virtual Extensible Local Area Network (VXLAN), Secure Shell (SSH) tunnelling, Hyper Text Transfer Protocol (HTTP) tunnelling, Internet Configuration Management Protocol (ICMP) tunnelling, General Packet Radio Service (GPRS) Tunnelling Protocol (GTP), Multiprotocol Label Switching (MPLS) tunnelling, and Virtual private network (VPN) tunnelling.

11. The network device as claimed in claim 7 , wherein a network device present at the first end of the network tunnel appends the information present in the first data packet obtained as the output of the multicast network connectivity determining function and the information present in the second data packet obtained as the output of the network route analysis function.

12. The network device as claimed in claim 7 , wherein an output of the network route analysis function includes details of the network devices with which communication could be established, and wherein the network devices are present in one or more network paths.

13. A non-transitory machine-readable storage medium that stores instructions which, when executed by a processor, perform a plurality of operations comprising:

sending a query message through a tunnel interface present in an overlay network configured over an underlay network, wherein the query message determines connectivity to network devices present in the overlay network, and the underlay network provides a physical infrastructure supporting movement of data of the overlay network;

tracing, while an upstream interface is a network tunnel having a first end and a second end, a unicast path from the first end to the second end of the network tunnel, using a network route analysis function;

determining that a destination device present on the second end of the network tunnel is not reachable;

appending information present in a first data packet obtained as an output of a multicast network connectivity determining function and information present in a second data packet obtained as an output of the network route analysis function to produce an appended result; and

send the appended result to a host device that initiated fault analysis.