System and method for reliable virtual bi-directional data stream communications with single socket point-to-multipoint capability

• US 8,478,890 B2
• Filed: 07/15/2011
• Issued: 07/02/2013
• Est. Priority Date: 07/15/2011
• Status: Active Grant

• Current Assignee: Damaka, Inc.
• Original Assignee: Damaka, Inc.
• Inventors: Chaturvedi, Sivakumar R., Gundabathula, Satish, Krishnan, Rajaraman
• Primary Examiner(s): Swearingen, Jeffrey R
• Application Number:
  US13/183,587
• Publication Number:
  US 20130019025A1
• Time in Patent Office: 718 Days
• Field of Search: 709/231
• US Class Current: 709/231
• CPC Class Codes: H04L 1/1835 Buffer management
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 61/2553 Binding renewal aspects, e.g. using keep-alive messages
• CPC Class Codes: H04L 61/256 NAT traversal
• CPC Class Codes: H04L 61/2592 using tunnelling or encapsulation
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/762 at the source reformatting of additional data in video distribution servers H04N21/2355
• CPC Class Codes: H04L 65/764 at the destination reformatting of additional data in video clients H04N21/4355
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 67/141 Setup of application sessions admission control or resource allocation in data switching networks H04L47/70
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols

Abstract

An improved system and method are disclosed for reliable virtual bi-directional data stream (RVBDDS) connections. In one example, two communication devices create and exchange streaming data packets that are encapsulated in connection-less transport layer packets. The streaming data packets contain information used in managing the RVBDDS connection between the two devices.

Claims

1. A method for streaming data using a virtual bi-directional data stream between a first communication device and a second communication device comprising:

creating, by the first device, a streaming data packet D1;

inserting, by the first device, a data segment and D1 into a payload section of a connection-less transport layer packet, wherein at least one of D1 and the connection-less transport layer packet includes a send field identifying a starting location in the data stream of the data segment to be sent with D1, an acknowledgement (ACK) field identifying a location in the data stream up to which all data has been received by the first device, a unique identifier (UID) identifying a connection used by the first device for the data stream, a window field identifying an amount of space available in a receive buffer of the first device, a packet type field, a pad field identifying an amount of padding used to ensure D1 has a predefined length, a network address of the first device, a network address of the second device, and a length of the connection-less transport layer packet;

sending, by the first device, the connection-less transport layer packet to the second device;

obtaining, by the first device, a current round trip time (RTT) that is based on first and second RTTs of packets previously sent from the first device to the second device and a configurable RTT variation factor, wherein the obtaining includes calculating, by the first device, the current RTT as the RTT for a streaming data packet D2 previously sent from the first device to the second device as RTT=RTT+((CurrRTT−

OldRTT)*1/M), wherein CurrRTT represents the first RTT of a streaming data packet D3 that was sent prior to D2 from the first device to the second device, OldRTT represents the second RTT of a streaming data packet D4 that was sent prior to D3 from the first device to the second device, and M represents the configurable RTT variation factor;

obtaining, by the first device, a current RTT variance that is based on a previous RTT variance, the first and second RTTs, and a configurable RTT variance variation factor, wherein the obtaining includes calculating, by the first device, the current RTT variance (RTTvar) as the RTTvar that was calculated for D2 as RTTvar=RTTvar+((CurrRTTVar−

Abs(CurrRTT−

OldRTT))*1/N), wherein CurrRTTVar represents an RTTvar of D3 and is the previous RTT variance, and N represents the configurable RTT variance variation factor;

calculating, by the first device, a timeout for D1 based on the current RTT and the current RTT variance; and

resending, by the first device, D1 if the timeout does not exceed a predefined timeout limit and if an ACK for D1 has not been received from the second device.

2. The method of claim 1 wherein calculating, by the first device, the timeout for D1 as timeout=RTT*X+RTTvar*Y, wherein X is a multiple of the RTT of D2 and Y is a timeout variance based on a percentage of streaming data packet RTTs.

3. The method of claim 1 further comprising, if the timeout does not exceed the predefined timeout limit and if the ACK for D1 has not been received from the second device, calculating, by the first device, a new timeout for D1 based on a new RTT and the current RTT variance, wherein the new RTT is obtained by increasing the current RTT by a defined time backoff factor.

4. The method of claim 1 further comprising:

receiving, by the first device, a streaming data packet D2 from the second device; and

inserting, by the first device, an ACK into the ACK field of D1, wherein the ACK acknowledges receipt of D2.

5. The method of claim 1 further comprising:

initiating, by the first device, the connection with the second device;

establishing, by the first device, the connection for the data stream with the second device; and

obtaining, by the first device, a remote window size of the second device during the establishment of the connection, wherein the remote window size identifies an amount of available space on the second device for the data stream.

6. The method of claim 1 further comprising:

receiving, by the first device, a request for the connection from the second device; and

sending, by the first device, a window size of the first device to the second device during the establishment of the connection, wherein the window size identifies an amount of available space on the first device for the data stream.

7. The method of claim 6 further comprising inserting an updated window size into the window field of D1.

8. The method of claim 1 wherein the first and second devices are peer-to-peer devices that communicate directly with each other and wherein the method further includes establishing, by the first device, a peer-to-peer session for the connection with the second device.

9. The method of claim 8 wherein signaling between the first and second devices is Session Initiation Protocol (SIP) compliant signaling.

10. The method of claim 9 wherein the connection-less transport layer packet is a User Datagram Protocol (UDP) packet.

11. The method of claim 1 wherein creating, by the first device, the streaming data packet D1 includes creating D1 with the send field, the ACK field, the UID, the window field, the packet type field, and the pad field, and wherein the network address of the first device, the network address of the second device, and the length of the connection-less transport layer packet are contained in the connection-less transport layer packet and not D1.

12. A method for streaming data using a virtual bi-directional data stream between a first communication device and a second communication device comprising:

creating, by the first device, a streaming data packet D1;

inserting, by the first device, a data segment and D1 into a payload section of a connection-less transport layer packet, wherein at least one of D1 and the connection-less transport layer packet includes a send field identifying a starting location in the data stream of the data segment to be sent with D1, an acknowledgement (ACK) field identifying a location in the data stream up to which all data has been received by the first device, a unique identifier (UID) identifying a connection used by the first device for the data stream, a window field identifying an amount of space available in a receive buffer of the first device, a packet type field, a pad field identifying an amount of padding used to ensure D1 has a predefined length, a network address of the first device, a network address of the second device, and a length of the connection-less transport layer packet

sending, by the first device, the connection-less transport layer packet to the second device;

obtaining, by the first device, a current round trip time (RTT) that is based on first and second RTTs of packets previously sent from the first device to the second device and a configurable RTT variation factor;

obtaining, by the first device, a current RTT variance that is based on a previous RTT variance, the first and second RTTs, and a configurable RTT variance variation factor;

calculating, by the first device, a timeout for D1 based on the current RTT and the current RTT variance;

resending, by the first device, D1 if the timeout does not exceed a predefined timeout limit and if an ACK for D1 has not been received from the second device;

receiving, by the first device, an ACK from the second device acknowledging receipt of D1 by the second device prior to resending the connection-less transport layer packet by the first device, wherein receipt of the ACK stops the first device from resending the connection-less transport layer packet;

determining, by the first device, whether the segment has been retransmitted if the ACK has been received from the second device; and

calculating a new RTT and a new RTTVar based on D1 if the segment has not been retransmitted, wherein calculating the new RTT and new RTTVar based on D1 includes;

calculating the new RTT as RTT=RTT+((CurrRTT−

OldRTT)*1/M), wherein CurrRTT represents the RTT of D2 and OldRTT represents the RTT of D3; and

calculating the new RTTvar as RTTvar=RTTvar+((CurrRTTVar−

Abs(CurrRTT−

OldRTT))*1/N), wherein CurrRTTVar represents the RTTvar of D2.

13. A method for streaming data using a virtual bi-directional data stream between a first device and a second device comprising:

establishing, by the first device, a virtual bi-directional data stream connection with the second device;

receiving, by the first device, a streaming data packet D1 from the second device;

creating, by the first device, a streaming data packet D2 for a segment to be sent from the first device to the second device via the connection, wherein D2 has a send field identifying a location of the data segment in the data stream, an acknowledgement (ACK) field for D1, a unique identifier identifying the connection used by the first device for the data stream, a packet type field, and a window value identifying an amount of space available in a receive buffer of the first device;

creating, by the first device, a connection-less transport layer packet containing an IP address of the first device, an IP address of the second device, a length of the connection-less transport layer packet, the segment, and D2;

sending, by the first device, the connection-less transport layer packet to the second device;

calculating, by the first device, a timeout for D2 based on a round trip time (RTT) and an RTT variance (RTTvar), wherein the RTT and the RTTvar are based on streaming data packets D3 and D4 previously sent from the first device to the second device, wherein RTT is calculated as RTT=RTT+((CurrRTT−

OldRTT)*1/M), wherein CurrRTT represents the RTT of D3, OldRTT represents the RTT of D4, and M represents a configurable RTT variation factor, and wherein RTTvar is calculated as RTTvar=RTTvar+((CurrRTTVar−

Abs(CurrRTT−

OldRTT))*1/N), wherein CurrRTTVar represents the RTT variance of D3, and N represents a configurable RTT variance variation factor; and

resending, by the first device, D2 if the timeout does not exceed a predefined timeout limit and if an ACK for D2 has not been received from the second device.

14. The method of claim 13 wherein receiving, by the first device, D1 from the second device includes:

receiving, by the first device, a connection-less transport layer packet associated with the data stream from the second device; and

extracting, by the first device, D1 and a segment of the data stream from the connection-less transport layer packet.

15. The method of claim 14 further comprising obtaining from D1, by the first device, a send field value identifying a starting location in the data stream of the segment sent with D1, an ACK field value identifying a location in the data stream up to which all data has been received by the second device, a UID identifying a connection used by the second device for the data stream, a window field value identifying an amount of space available in a receive buffer of the second device, and a packet type field value.

16. The method of claim 15 further comprising updating, by the first device, a remote window value based on the window field value of D1.

17. The method of claim 15 further comprising updating, by the first device, a sent pointer in a send buffer of the first device based on the ACK field value of D1.

18. The method of claim 13 wherein the virtual bi-directional data stream connection can be initiated by either of the first or second devices.

19. The method of claim 13 wherein establishing, by the first device, the virtual bi-directional data stream connection with the second device includes establishing a peer-to-peer session between the first and second devices, wherein signaling and data are communicated directly between the first and second devices.

20. A communication device comprising:

a network interface configured to send and receive communications via at least one of a wireless and a wireline network;

a controller coupled to the network interface; and

a memory coupled to the controller, the memory having a plurality of instructions stored thereon for execution by the controller, the instructions including instructions for;

establishing, by the first device, a virtual bi-directional connection with a second communication device;

receiving, by the first device, a streaming data packet D1 from the second device;

creating, by the first device, a streaming data packet D2 for a segment to be sent from the first device to the second device via the connection, wherein D2 has a send field identifying a starting location of the data segment in the data stream, an acknowledgement (ACK) field for D1, a unique identifier identifying the connection used by the first device for the data stream, a packet type, and a window value identifying an amount of space available in a receive buffer of the first device;

creating, by the first device, a connection-less transport layer packet containing an IP address of the first device, an IP address of the second device, a length of the connection-less transport layer packet, the segment, and D1;

sending, by the first device, the connection-less transport layer packet to the second device;

calculating, by the first device, a timeout for D2 based on a round trip time (RTT) and an RTT variance (RTTvar), wherein the RTT and the RTTvar are based on streaming data packets D3 and D4 previously sent from the first device to the second device, wherein RTT is calculated as RTT=RTT+((CurrRTT−

OldRTT)*1/M), wherein CurrRTT represents the RTT of D3, OldRTT represents the RTT of D4, and M represents a configurable RTT variation factor, and wherein RTTvar is calculated as RTTvar=RTTvar+((CurrRTTVar−

Abs(CurrRTT−

OldRTT))*1/N), wherein CurrRTTVar represents the RTT variance of D3, and N represents a configurable RTT variance variation factor; and

resending, by the first device, D1 if the timeout does not exceed a predefined timeout limit and if an ACK for D1 has not been received from the second device.

21. The communication device of claim 20 wherein the instructions further include instructions for establishing, by the first device, a peer-to-peer session for the connection with the second device.

22. The communication device of claim 21 wherein signaling between the first and second devices is Session Initiation Protocol (SIP) compliant signaling.

23. The communication device of claim 22 wherein the connection-less transport layer packet is a User Datagram Protocol (UDP) packet.