Supporting internet protocol version 4 (IPv4) extension headers

1. A method implemented by a network element (NE), comprising:

receiving, by a receiver of the NE, an Internet Protocol (IP) version 4 (IPv4) packet from another NE, wherein the IPv4 packet comprises an IPv4 header, a plurality of extension headers, and upper layer data, wherein the IPv4 header comprises a first protocol field and a total length field, wherein the first protocol field indicates a protocol number associated with a first extension header of the plurality of extension headers, wherein the total length field indicates a total length of the IPv4 packet, and wherein the IPv4 packet comprises a field indicating a length of the plurality of extension headers;

determining, by a processor coupled to the receiver, a protocol used to encode the upper layer data of the IPv4 packet based on a value indicated in a last protocol field of a last extension header of the plurality of extension headers; and

processing, by a processor coupled to the receiver, the IPv4 packet based on the length of the plurality of extension headers, the total length of the IPv4 packet, and the protocol used to encode the upper layer data of the IPv4 packet.

2. The method of claim 1 , wherein the IPv4 packet further comprises a payload.

3. The method of claim 1 , wherein processing, by the processor, the IPv4 packet further comprises determining a start point of the upper layer data of the IPv4 packet based on the total length of the IPv4 header and the length of the plurality of extension headers, wherein the upper layer data comprises an upper layer protocol header and a payload.

4. The method of claim 1 , wherein each of the plurality of extension headers comprises a protocol number for a next extension header.

5. The method of claim 1 , wherein each of the plurality of extension headers is at least one of a hop-by-hop extension header or a destination extension header.

6. The method of claim 1 , wherein an options field of the IPv4 header comprises the length of the plurality of extension headers.

7. The method of claim 1 , wherein one of the plurality of extension headers comprises the length of the plurality of extension headers.

8. A network element (NE), comprising:

a memory storage comprising instructions; and

one or more processors in communication with the memory storage, wherein the one or more processors execute the instructions to:

obtain an Internet Protocol (IP) version 4 (IPv4) packet, wherein the IPv4 packet comprises an IPv4 header, a plurality of extension headers, and upper layer data, wherein the IPv4 header comprises a first protocol field and a total length field, wherein the first protocol field indicates a protocol number associated with a first extension header of the plurality of extension headers, wherein the total length field indicates a total length of the IPv4 packet, and wherein the IPv4 packet comprises a field indicating a length of the plurality of extension headers;

determine a protocol used to encode the upper layer data of the IPv4 packet based on a value indicated in a last protocol field of a last extension header of the plurality of extension headers; and

transmit the IPv4 packet to another NE.

9. The NE of claim 8 , wherein the one or more processors execute the instructions to encapsulate the IPv4 packet to include the IPv4 header and the plurality of extension headers, and wherein the IPv4 packet further comprises a payload.

10. The NE of claim 8 , wherein the protocol number associated with the first extension header identifies a type of the first extension header.

11. The NE of claim 8 , wherein the first extension header comprises a second protocol number associated with a second extension header of the plurality of extension headers.

12. The NE of claim 8 , wherein an options field of the IPv4 header comprises the length of the plurality of extension headers.

13. The NE of claim 8 , wherein the first extension header comprises the length of the plurality of extension headers.

14. A network element (NE), comprising:

a receiver configured to receive an Internet Protocol (IP) version 4 (IPv4) packet, wherein the IPv4 packet comprises an IPv4 header, a plurality of extension headers, and upper layer data, wherein the IPv4 header comprises a first protocol field and a length field, wherein the first protocol field indicates a protocol number associated with a first extension header, wherein the total length field indicates a total length of the IPv4 packet, and wherein the IPv4 packet comprises a field indicating a length of the plurality of extension headers;

a processor coupled to the receiver and configured to determine a protocol used to encode the upper layer data of the IPv4 packet based on a value indicated in a last protocol field of a last extension header of the plurality of extension headers; and

a transmitter coupled to the processor and configured to transmit the IPv4 packet to another NE.

15. The NE of claim 14 , wherein the protocol number identifies a type of the extension header.

16. The NE of claim 14 , wherein each of the extension headers comprises a protocol number for a next extension header.

17. The NE of claim 14 , wherein an options field of the IPv4 header comprises the length of the plurality of extension headers.

18. The NE of claim 14 , wherein one of the extension headers included in the IPv4 packet comprises the length of the plurality of extension headers.