Flow control with network named fragments

• US 10,355,999 B2
• Filed: 09/23/2015
• Issued: 07/16/2019
• Est. Priority Date: 09/23/2015
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Mosko, Marc E., Wood, Christopher A.
• Primary Examiner(s): Foud, Hicham B
• Application Number:
  US14/863,307
• Publication Number:
  US 20170085491A1
• Time in Patent Office: 1,392 Days
• Field of Search: None
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/33 using forward notification

Abstract

One embodiment provides a system that facilitates efficient and secure flow control based on a fragmentation protocol. During operation, the system receives, by an intermediate node, a first fragment which is a fragment of a content object that is fragmented into a plurality of fragments, wherein the plurality of fragments includes at least one named fragment, which indicates a name associated with the content object, the name being a hierarchically structured variable-length identifier that comprises contiguous name components ordered from a most general level to a most specific level. The intermediate node detects a congestion, and sets an indicator for congestion notification in the received fragment. The intermediate node forwards the received fragment, and drops a second fragment received after the forwarded fragment.

Claims

1. A computer system for facilitating forwarding of packets, the system comprising

a processor;

and

a storage device storing instructions that when executed by the processor cause the processor to perform a method, the method comprising;

receiving, by an intermediate node, a first fragment which is a fragment of a content object that is fragmented into a plurality of fragments,

wherein the plurality of fragments includes at least one named fragment, which indicates a name associated with the content object, the name being a hierarchically structured variable-length identifier that comprises contiguous name components ordered from a most general level to a most specific level;

detecting a congestion;

when there is congestion;

setting an indicator for congestion notification in the received first fragment;

forwarding the received first fragment;

dropping a second fragment received after the forwarded first fragment;

receiving a third fragment comprising a congestion notification;

identifying an alternate path not associated with the congestion;

generating an interest for a remainder of the plurality of fragments based on the congestion notification of the third fragment; and

forwarding the interest based on an interface associated with the alternate path.

2. The computer system of claim 1, wherein in response to detecting the congestion, the method further comprises:

determining that the received first fragment indicates an optimal position to restart a flow of the fragment,

wherein the indicator for congestion notification is an indicator for early congestion notification.

3. The computer system of claim 1, wherein the method further comprises:

determining that the received first fragment indicates an optimal position to restart a flow of the fragment, which involves;

determining that the received first fragment is a previous fragment that directly precedes a named fragment.

4. The computer system of claim 1, wherein the method further comprises:

determining that the received first fragment does not indicate an optimal position to restart a flow of the fragment,

wherein the indicator for congestion notification is an indicator for early discarding.

5. The computer system of claim 1, wherein the congestion notification in the received third fragment is an indicator for early congestion, and wherein the method further comprises:

generating the interest further comprises, generating the interest for the remainder of the plurality of fragments starting from a next fragment that directly follows the received third fragment; and

setting the indicator for early congestion notification in the received third fragment to an inactive value.

6. The computer system of claim 5, wherein generating the interest further comprises:

computing an intermediate state for the next fragment based on a hash function performed on an intermediate state from the received third fragment, wherein the received third fragment indicates an intermediate state which is based on a hash function performed on an intermediate state from a previous fragment and data included in the received third fragment;

determining a payload size for the remainder of the plurality of fragments starting from the next fragment; and

including in a name for the interest based on the computed intermediate state and the determined payload size.

7. The computer system of claim 1, wherein the congestion notification in the received third fragment is an indicator for early discarding, and wherein the method further comprises:

identifying a previously received named fragment that is closest in order to the received third fragment;

generating the interest further comprises, generating the interest for the remainder of the plurality of fragments starting from the previously received named fragment; and

setting the indicator for early discarding in the received third fragment to an inactive value.

8. The computer system of claim 7, wherein generating the interest further comprises:

determining a payload size for the remainder of the plurality of fragments starting from the previously received named fragment; and

including in a name for the interest an intermediate state for the previously received named fragment and the determined payload size,

wherein the intermediate state for the previously received named fragment is based on a hash function performed on an intermediate state from a previous fragment that directly precedes the previously received named fragment and data included in the previously received named fragment.

9. The computer system of claim 1, wherein a name for an interest includes a digest for the content object, and a number indicating a byte offsetthat corresponds to a starting byte for the received first fragment or a previously received named fragment closest in order to the received first fragment.

10. A computer system for facilitating forwarding of packets, the system comprising:

a processor; and

a storage device storing instructions that when executed by the processor cause the processor to perform a method, the method comprising;

receiving, by a content requesting device, a first fragment which is a fragment of a content object message that is fragmented into a plurality of fragments,

wherein the plurality of fragments includes at least one named fragment, which indicates a name associated with the content object, the name being a hierarchically structured variable-length identifier that comprises contiguous name components ordered from a most general level to a most specific level;

determining that an indicator for congestion notification in the received first fragment is set;

updating a corresponding entry in a pending interest table based on a payload offset of the received first fragment or of a previously received named fragment that is closest in order to the received first fragment, wherein the payload offset is a number indicating a byte offset; and

generating an interest for a remainder of the plurality of fragments starting from a named fragment.

11. The computer system of claim 10, wherein the indicator for congestion notification is an indicator for early congestion notification, wherein the named fragment is a next fragment that directly follows the received first fragment, and wherein generating the interest further comprises:

computing an intermediate state for the next fragment based on a hash function performed on an intermediate state from the received first fragment, wherein the received first fragment indicates an intermediate state which is based on a hash function performed on an intermediate state from a previous fragment and data included in the received first fragment;

determining a payload size for the remainder of the plurality of fragments starting from the next fragment; and

including in a name for the interest based on the computed intermediate state and the determined payload size.

12. The computer system of claim 10, wherein the byte offset corresponds to a starting byte for the received first fragment.

13. The computer system of claim 10, wherein the indicator for congestion notification is an indicator for early discarding, wherein the named fragment is the previously received named fragment that is closest in order to the received first fragment, and wherein generating the interest further comprises:

determining a payload size for the remainder of the plurality of fragments starting from the previously received named fragment; and

including in a name for the interest an intermediate state for the previously received named fragment and the determined payload size,

wherein the intermediate state for the previously received named fragment is based on a hash function performed on an intermediate state from a previous fragment that directly precedes the previously received named fragment and data included in the previously received named fragment.

14. The computer system of claim 13, wherein the byte offset corresponds to a starting byte for the previously received named fragment.

15. The computer system of claim 10, wherein the method further comprises:

in response to determining that the indicator for congestion notification in the received first fragment is not set, processing the received first fragment forreassembly.

16. A computer-implemented method for forwarding packets, the method comprising:

receiving, by an intermediate node, a first fragment which is a fragment of a content object that is fragmented into a plurality of fragments,

wherein the plurality of fragments includes at least one named fragment, which indicates a name associated with the content object, the name being a hierarchically structured variable-length identifier that comprises contiguous name components ordered from a most general level to a most specific level;

detecting a congestion;

when there is congestion;

setting an indicator for congestion notification in the received first fragment;

forwarding the received first fragment;

dropping a second fragment received after the forwarded first fragment;

receiving a third fragment comprising a congestion notification;

identifying an alternate path not associated with the congestion;

generating an interest for a remainder of the plurality of fragments based on the congestion notification of the third fragment; and

forwarding the interest based on an interface associated with the alternate path.

17. The method of claim 16, wherein in response to detecting the congestion, the method further comprises:

determining that the received first fragment indicates an optimal position to restart a flow of the fragment,

wherein the indicator for congestion notification is an indicator for early congestion notification.

18. The method of claim 16, further comprising:

determining that the received first fragment indicates an optimal position to restart a flow of the fragment, which involves;

determining that the received first fragment is a previous fragment that directly precedes a named fragment.

19. The method of claim 16, further comprising:

determining that the received first fragment does not indicate an optimal position to restart a flow of the fragment,

wherein the indicator for congestion notification is an indicator for early discarding.

20. The method of claim 16, further comprising wherein the congestion notification in the received third fragment is an indicator for early congestion, the method further comprising:

generating the interest further comprising, generating the interest for the remainder of the plurality of fragments starting from a next fragment that directly follows the third fragment; and

setting the indicator for early congestion notification in the received third fragment to an inactive value.

21. The method of claim 20, wherein generating the interest further comprises:

computing an intermediate state for the next fragment based on a hash function performed on an intermediate state from the received first fragment, wherein the received first fragment indicates an intermediate state which is based on a hash function performed on an intermediate state from a previous fragment and data included in the received first fragment;

determining a payload size for the remainder of the plurality of fragments starting from the next fragment; and

including in a name for the interest the computed intermediate state and the determined payload size.

22. The method of claim 16, wherein the congestion notification in the received third fragment is an indicator for early discarding, the method further comprising:

identifying a previously received named fragment that is closest in order to the received third fragment;

generating the interest further comprising, generating the interest for the remainder of the plurality of fragments starting from the previously received named fragment; and

setting the indicator for early discarding in the received third fragment to an inactive value.

23. The method of claim 22, wherein generating the interest further comprises:

determining a payload size for the remainder of the plurality of fragments starting from the previously received named fragment; and

including in a name for the interest an intermediate state for the previously received named fragment and the determined payload size,

wherein the intermediate state for the previously received named fragment is based on a hash function performed on an intermediate state from a previous fragment that directly precedes the previously received named fragment and data included in the previously received named fragment.

24. The method of claim 16, wherein a name for an interest includes a digest for the content object, and a number indicating a byte offset that corresponds to a starting byte for the received first fragment or a previously received named fragment closest in order to the received first fragment.