Maximum transmission unit tuning mechanism for a real-time transport protocol stream

• US 7,680,047 B2
• Filed: 11/22/2005
• Issued: 03/16/2010
• Est. Priority Date: 11/22/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bangalore, Manjunath S., Nguyen, Son D., Khurana, Vikram, Vadlakonda, Sravan
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): SAMUEL, DEWANDA A
• Application Number:
  US11/284,483
• Publication Number:
  US 20070115963A1
• Time in Patent Office: 1,575 Days
• Field of Search: 370/236, 370/252, 370/235, 370/230.1, 370/389
• US Class Current: 370/235
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/267 sent by the destination endpoint network streaming of media packets with control of the source by the destination H04L65/613
• CPC Class Codes: H04L 65/1101 Session protocols
• 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 65/752 adapting media to network capabilities
• CPC Class Codes: H04L 65/80 Responding to QoS

Abstract

A Real-Time Protocol (RTP) source node of a network operates to send a first data packet of a first size to a destination node over a path of the network that includes a plurality of intermediate nodes, at least one of the intermediate nodes having a maximum transmission unit (MTU) size smaller than the first size such that fragmentation of the first data packet occurs. The destination node sends back to the source node a RTCP report that includes a number of fragments received and a largest minimum data packet size. In response, the source node sends subsequent data packets having a second size less than or equal to the largest data packet size of the fragments. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Claims

1. A method of operation for a Real-Time Protocol (RTP) source node of a network, the method comprising:

sending, the RTP source node, a first data packet of a first size to a destination node over a path of the network that includes a plurality of intermediate nodes, at least one of the intermediate nodes having a maximum transmission unit (MTU) size smaller than the first size such that fragmentation of the first data packet occurs;

receiving, by the RTP source node, a RTP Control Protocol (RTCP) report from the destination node, the RTCP report which comprises an RTCP Extended Report data packet type containing information that includes a number of fragments received and a largest data packet size; and

sending, by the RTP source node, subsequent data packets having a second size less than or equal to the largest data packet size.

2. The method of claim 1 wherein the largest data packet size is greater than a predetermined data packet size.

3. The method of claim 1 further comprising incrementing the second size of the subsequent date packets by a certain amount after a predetermined time elapses.

4. A method of operation for a Real-Time Protocol (RTP) destination node of a network, the method comprising:

receiving a first data packet of a first size as a plurality of data packet fragments, each of the data packet fragments having a size smaller than the first size due to fragmentation of the first data packet by one or more intermediate nodes of the network, the first data packet being sent over the network by a RTP source node;

sending a RTP Control Protocol (RTCP) report back to the RTP source node, the RTCP report containing information that includes a number of the data packet fragments received and a largest data packet size of the data packet fragments; and

receiving subsequent data packets sent by the RTP source node having a second size less than or equal to the largest data packet size.

5. The method of claim 4 wherein the RTCP report comprises an RTCP Extended Report data packet type.

6. The method of claim 4 wherein the largest data packet size is greater than a predetermined data packet size.

7. A node of a network for originating a Real-Time Protocol (RTP) data packet stream comprising:

an interface coupled to the network;

a processor operable to send via the interface a first data packet of a first size to a RTP destination node over the network, the processor being further operable to receive a RTP Control Protocol (RTCP) report from the destination node, the RTCP report containing information indicating that the first data packet was received as a plurality of fragments, the information including a number of the fragments received and a largest data packet size of the fragments, in response to the RTCP report the processor sending subsequent data packets to the RTP destination node over the network, the subsequent data packets having a second size less than or equal to the largest data packet size;

wherein the processor is further operable to increment the second size of the subsequent data packets after a certain number of RTCP reports are received indicating no fragmentation.

8. The node of claim 7 wherein the RTCP report comprises an RTCP Extended Report data packet type.

9. The node of claim 7 wherein the largest data packet size is greater than a predetermined data packet size.

10. A node of a network comprising:

an interface coupled to the network;

a processor operable to receive via the interface a first Real-Time Protocol (RTP) data packet sent by a RTP source node over the network, the processor being further operable to send a RTP Control Protocol (RTCP) report back to the RTP source node over the network, the RTCP report comprising an RTCP Extended Report data packet type that contains information indicating that the first data packet was received as a plurality of fragments, the information including a number of the fragments received and a largest data packet size of the fragments.

11. The node of claim 10 wherein the largest data packet size is greater than a predetermined data packet size.

12. A node of a network for originating a Real-Time Protocol (RTP) data packet stream comprising:

an interface coupled to the network;

means for sending via the interface a first data packet of a first size to a destination node over the network via a plurality of intermediate nodes, at least one of the intermediate nodes having a maximum transmission unit (MTU) size smaller than the first size such that the first data packet is fragmented, and for receiving a RTP Control Protocol (RTCP) report from the destination node, the RTCP report comprising an RTCP Extended Report data packet type that contains information which includes a number of the fragments received and a largest data packet size of the fragments, in response the means sending subsequent data packets to the destination node, the subsequent data packets having a second size less than or equal to the largest data packet size, the means further for incrementally increasing the second size of the subsequent data packets after a time period until another RTCP report is received from the destination node that indicates fragmentation has occurred.