SYNCHRONIZING SEQUENCE NUMBERS AMONG PEERS IN A NETWORK

• US 20090135827A1
• Filed: 11/28/2007
• Published: 05/28/2009
• Est. Priority Date: 11/28/2007
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Dewan, Prashant, Long, Men
• Granted Patent: US 7,778,166 B2
• Time in Patent Office: Days
• US Class Current: 370/394
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 63/06 for supporting key management in a packet data network cryptographic mechanisms or cryptographic arrangements for key management H04L9/08
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 63/0846 using time-dependent-passwords, e.g. periodically changing passwords
• CPC Class Codes: H04L 63/164 at the network layer

Abstract

A method and system are disclosed. In one embodiment the method includes a first device sending a stream of packets in a sequence across a network to a second device. In the sequence of packets there are a number of data packets and one or more synchronization packets. The synchronization packets are interspersed throughout the data packets. The method also includes the second device being capable of dropping any of the received data packets in the sequence arriving more than a first delta of time threshold value after the arrival of the most recent synchronization packet.

Claims

1. A method, comprising:

a first device sending a stream of packets in a sequence across a network to a second device, the packets comprising a plurality of data packets and one or more synchronization packets interspersed in the plurality of data packets; and

the second device dropping any of the received data packets in the sequence arriving more than a first delta of time threshold value after the arrival of a most recent synchronization packet of the one or more synchronization packets.

2. The method of claim 1, wherein each of the one or more synchronization packets comprises at least a security parameters index key, a network-common time stamp retrieved from the network, and one or more updated sequence numbers.

3. The method of claim 2, further comprising:

after receiving a first synchronization packet, the second device comparing the network-common time stamp in the first synchronization packet with a current time received from the network; and

the second device updating one or more local sequence numbers with the one or more updated sequence numbers from the first synchronization packet when the network-common time stamp and the current time received from the network differ by less than a second delta of time threshold value.

4. The method of claim 1, wherein each of the plurality of data packets comprises at least a security parameters index key and a packet sequence number.

5. The method of claim 4, further comprising:

after receiving a first data packet, the second device decrypting the received first data packet when the security parameters index key in the first data packet is currently stored in a local security parameters index storage table; and

the second device dropping the first data packet when the security parameters index key in the first data packet is not stored in the local security parameters index storage table.

6. The method of claim 5, further comprising:

after decrypting the first data packet, the second device sending the first data packet to the network interface protocol stack when the packet sequence number in the first data packet is greater than a locally stored sequence number for the stream; and

the second device dropping the first data packet when the packet sequence number in the first data packet is not greater than the locally stored sequence number for the stream.

7. The method of claim 1, further comprising:

the first device updating a timestamp counter immediately upon sending each of the one or more synchronization packets.

8. The method of claim 7, further comprising:

prior to sending a next data packet of the plurality of data packets, the first device checking a current delta of time between the current time and the time stamp of the most recently sent synchronization packet; and

the first device sending a next synchronization packet to the second device prior to sending the next data packet of the plurality of data packets when the current delta of time is greater than the first delta of time threshold value.

9. A system, comprising:

a network interconnect;

a first device, coupled to the network interconnect, to send a stream of packets in a sequence, across the network interconnect, to a second device coupled to the network interconnect, the packets comprising a plurality of data packets and one or more synchronization packets interspersed in the plurality of data packets; and

the second device to drop any of the received data packets in the sequence arriving more than a first delta of time threshold value after the arrival of a most recent synchronization packet of the one or more synchronization packets.

10. The system of claim 9, wherein each of the one or more synchronization packets comprises at least a security parameters index key, a network-common time stamp retrieved from the network, and one or more updated sequence numbers.

11. The system of claim 10, wherein the second device is further operable to:

compare the network-common time stamp in a first synchronization packet with a current time received from the network; and

update one or more local sequence numbers with the one or more updated sequence numbers from the first synchronization packet when the network-common time stamp and the current time received from the network differ by less than a second delta of time threshold value.

12. The system of claim 9, wherein each of the plurality of data packets comprises at least a security parameters index key and a packet sequence number.

13. The system of claim 12, wherein the second device is further operable to:

after receiving a first data packet, decrypt the received first data packet when the security parameters index key in the first data packet is currently stored in a local security parameters index storage table; and

drop the first data packet when the security parameters index key in the first data packet is not stored in the local security parameters index storage table.

14. The system of claim 13, wherein the second device is further operable to:

send the first data packet to the network interface protocol stack when the packet sequence number in the first data packet is greater than a locally stored sequence number for the stream; and

drop the first data packet when the packet sequence number in the first data packet is not greater than the locally stored sequence number for the stream.

15. The system of claim 9, wherein the first device is further operable to:

store a time stamp immediately upon sending each of the one or more synchronization packets;

prior to sending a next data packet of the plurality of data packets, check a current delta of time between the current time and the time stamp of the most recently sent synchronization packet; and

send a next synchronization packet to the second device prior to sending the next data packet of the plurality of data packets when the current delta of time is greater than the first delta of time threshold value.