Modified ethernet preamble for inter line card communications in a modular communication chassis

• US 10,341,470 B2
• Filed: 10/26/2016
• Issued: 07/02/2019
• Est. Priority Date: 09/25/2012
• Status: Active Grant

• Current Assignee: Accedian Networks Inc. (Cisco Systems, Inc.)
• Original Assignee: Accedian Networks Inc. (Cisco Systems, Inc.)
• Inventors: Viens, Yanick, Rochon, Steve
• Primary Examiner(s): Mew, Kevin D
• Application Number:
  US15/334,353
• Publication Number:
  US 20170048362A1
• Time in Patent Office: 979 Days
• Field of Search: 370392
• CPC Class Codes: H04L 12/2892 characterised by the access multiplexer architecture
• CPC Class Codes: H04L 12/462 LAN interconnection over a bridge based backbone
• CPC Class Codes: H04L 45/502 Frame based
• CPC Class Codes: H04L 45/74 Address processing for routing
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/9057 Arrangements for supporting packet reassembly or resequencing
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC

Abstract

A method of providing information regarding an Ethernet frame, within the Ethernet preamble of the Ethernet frame, comprises inserting into the Ethernet preamble an inter-line-card header that includes a start control character, a version number, a parity bit, a source port, a destination port, and a forwarding domain entry; and preserving said inter-line-card header, inside of said Ethernet preamble, in a Media Access Control (MAC) sub-layer in said Ethernet frame. The method may include a step of selecting the decoding format for the inter-line-card header corresponding to the version number and/or forwarding other Ethernet frames according to additional forwarding information provided by the forwarding domain entry. The inter-line-card header may be preserved in the MAC sub-layer by keeping the Ethernet preamble at the beginning of an Ethernet frame received over an Ethernet backplane, and passing the combined preamble and associated Ethernet frame to an inter-line-card header processing module.

Claims

1. A method for redefining a standard Ethernet preamble of an Ethernet frame to create an inter-line-card header used for switching said Ethernet frame across an Ethernet backplane of a communication chassis, within an Ethernet preamble of the Ethernet frame, said method comprising:

inserting into the Ethernet preamble an inter-line-card header that includes at least one information element; and

preserving said inter-line-card header, inside of said Ethernet preamble, in a Media Access Control (MAC) sub-layer in said Ethernet frame, to create a modified Ethernet preamble.

2. The method of claim 1 wherein said inter-line-card header further includes an action and action parameters.

3. The method of claim 2 in which said action includes controlling or modifying the associated Ethernet frame by:

pushing or popping an MPLS label,

adding an MPLS label,

setting the time to live (TTL) for an MPLS label,

decrementing an MPLS TTL,

setting an MPLS TTL to a specific value,

pushing or popping a VLAN tag,

setting or decrementing an Internet Protocol (IP) TTL field,

setting the committed information rate (CIR) and the excess information rate (EIR) to new values or

resetting the CIR and EIR to known values for the Ethernet Virtual Circuit to which the Ethernet frame belongs.

4. The method of claim 2 which includes applying said action parameters according to said action as decoded in said inter-line-card header.

5. The method of claim 1 wherein the information element is selected from the group consisting of:

a start control character,

a version number,

a parity bit,

a source port,

a destination port, and

a forwarding domain entry.

6. The method of claim 5 wherein said start control character indicates the beginning of a new Ethernet frame.

7. The method of claim 6 further comprising selecting a decoding format for said inter-line-card header corresponding to said version number.

8. The method of claim 6 wherein said parity bit is used to verify that said inter line card header is not corrupted.

9. The method of claim 6 wherein said source port identifies a source of the Ethernet frame.

10. The method of claim 6 wherein said destination port identifies a port on which to transmit the Ethernet frame.

11. The method of claim 6 further comprising forwarding other Ethernet frames according to additional forwarding information provided by said forwarding domain entry.

12. The method of claim 6 further comprising extracting said destination port from said inter-line-card header.

13. A method for redefining a standard Ethernet preamble of Ethernet frame to create an inter-line-card header used for switching said Ethernet frame across an Ethernet backplane of a communication chassis, within an Ethernet preamble of the Ethernet frame, said method comprising

modifying an Ethernet preamble comprised in the Ethernet frame to include an inter-line-card header that comprises at least one information element;

preserving said inter-line-card header, inside of said modified Ethernet preamble, in a Media Access Control (MAC) sub-layer in said Ethernet frame; and

wherein said inter-line-card header further includes an action and action parameters.

14. The method of claim 13, wherein the information element is selected from the group consisting of:

a start control character,

a version number,

a parity bit,

a source port,

a destination port, and

a forwarding domain entry.

15. The method of claim 14 wherein said start control character indicates the beginning of a new Ethernet frame.

16. The method of claim 14 further comprising selecting a decoding format for said inter-line-card header corresponding to said version number.

17. The method of claim 14 wherein said parity bit is used to verify that said inter line card header is not corrupted.

18. The method of claim 14 wherein said source port identifies a source of the Ethernet frame.

19. The method of claim 14 wherein said destination port identifies a port on which to transmit the Ethernet frame.

20. The method of claim 14 further comprising forwarding other Ethernet frames according to additional forwarding information provided by said forwarding domain entry.