Surrogate Stream for Monitoring Realtime Media

• US 20080310316A1
• Filed: 06/18/2007
• Published: 12/18/2008
• Est. Priority Date: 06/18/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Oran, David R., Gahm, Joshua B., Drisko, Robert Andrew, Faheem, Atif
• Granted Patent: US 7,835,406 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/06 Generation of reports
• CPC Class Codes: H04L 43/0829 Packet loss
• CPC Class Codes: H04L 43/087 Jitter
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04L 65/401 wherein the services involve a main real-time session and one or more additional parallel real-time or time sensitive sessions, e.g. white board sharing or spawning of a subconference
• CPC Class Codes: H04L 65/765 intermediate
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols

Abstract

In one embodiment, a separate surrogate monitor stream provides real-time media monitoring statistics for non-media savvy protocols. The surrogate monitor stream contains packet transmission parameters, such as sequence numbers and time stamps, for associated media packets in the non-savvy media stream. The surrogate monitor stream also contains checksums derived from the media packets. The checksums are used to correlate the packets in the surrogate monitor stream with the media packets in the media stream. The information in the surrogate monitor stream is then used in conjunction with the non-savvy media stream to provide real-time media monitoring without having to modify existing infrastructure. For example, head-end video servers do not have to add Real-time Transport Protocol (RTP) support or deal with protocol upgrades like RTP/UDP co-existence.

Claims

1. A method comprising:

receiving media packets for a media stream;

generating checksums for at least portions of the media packets;

identifying transmission parameters for the media packets;

combining the transmission parameters with the checksums for the same media packets into monitor packets; and

transmitting the monitor packets as a separate monitor stream for the media stream.

2. The method according to claim 1 wherein the media packets are User Datagram Protocol (UDP) packets that do not contain the transmission parameters and wherein both the media stream and monitor stream are sent to at least some of the same receivers so packet statistics for the media stream can be derived using the transmission parameters from the monitor stream.

3. The method according to claim 1 including:

identifying Real-Time Protocol (RTP) parameters for the media packets;

formatting the RTP parameters into RTP headers; and

forming the monitor packets that include the RTP headers and RTP payloads containing only the checksums for the same media packets.

4. The method according to claim 3 including combining the RTP packets for multiple different media packets into the same monitor packets.

5. The method of claim 4 including:

compressing the RTP headers for the multiple RTP packets in the same monitor packets; and

transmitting the monitor packets with compressed RTP headers over the monitor stream

6. An apparatus, comprising:

one or more processors; and

a memory coupled to the one or more processors comprising instructions executable by the processors, the processors operable when executing the instructions to;

generate checksums for media packets in a media stream;

identify transmission parameters associated with the media packets;

combine the transmission parameters associated with the media packets with the checksums generated for the same media packets forming monitor packets; and

transmit the monitor packets as supplemental monitoring information for the media stream.

7. The apparatus according to claim 6 wherein the one or more processors:

identify Real-Time Protocol (RTP) parameters for the media packets;

format the RTP parameters into RTP headers;

attach the RTP headers to the checksums for the same media packets to form the monitor packets; and

send the monitor packets to at least some of a same group of receivers receiving the media packets.

8. The apparatus according to claim 6 wherein the one or more processors negotiate a monitor stream session for transmitting the monitor packets separately from a media stream session used for transmitting the media packets.

9. The apparatus according to claim 6 wherein the one or more processors:

combine the transmission parameters and checksums for multiple different media packets into the same block monitor packets; and

send one or more of the block monitor packets to receivers.

10. The apparatus according to claim 6 wherein the one or more processors:

identify sequence numbers and timestamp values for the media packets;

format the sequence numbers and timestamp values into Real-Time Protocol (RTP) headers; and

combine the RTP headers with the checksums for the same media packets to form the monitor packets.

11. The apparatus according to claim 6 wherein the one or more processors are located either in a same server that transmits the media stream or located in a separate server from the server transmitting the media stream.

12. A method, comprising:

receiving media packets;

generating a checksum from the media packets;

receiving monitoring support packets that contain packet parameter information and checksums for the media packets;

using the checksums to correlate the monitoring support packets with corresponding media packets; and

using the packet parameter information in the monitoring support packets to monitor transmission metrics for the corresponding media packets.

13. The method according to claim 12 including:

receiving User Datagram Protocol (UDP) media packets that contain MPEG media payloads;

generating checksums for at least a portion of the UDP media packets; and

receiving Real-Time Transport Protocol (RTP) packets that contain the packet parameter information in RTP headers and contain the checksums in RTP packet payloads.

14. The method according to claim 13 wherein:

the UDP packets do not include sequence numbers or timestamps;

the RTP packets include sequence numbers and timestamps for the UDP packets; and

the sequence numbers and timestamps in the RTP packets are used to generate Real-Time Control Protocol (RTCP) reports for the UDP packets.

15. The method according to claim 12 including:

receiving batched monitoring support packets that contain the checksums and associated packet parameter information for multiple different media packets,

16. The method according to claim 15 including:

receiving the batched monitoring support packets with compressed headers;

decompressing the compressed headers;

assigning the packet parameter information from the decompressed headers to the media packets having the same checksums; and

generating metrics for the different media packets according to the assigned packet parameter information.

17. An apparatus, comprising:

one or more processors configured to receive both media packets from a media stream and monitor packets from a second separate monitor stream, the one or more processors identifying which monitor packets are associated with the media packets and then using packet transmission parameters in the identified monitor packets to generate packet transmission metrics for the media packets.

18. The apparatus according to claim 17 wherein the one or more processors generate checksums from the media packets and compare the generated checksums with checksums in the monitor packets to identify which monitor packets are associated with which media packets.

19. The apparatus according to claim 17 wherein the one or more processors are located in a same Set Top Box (STB) that receives and outputs the media stream.

20. The apparatus according to claim 17 wherein the one or more processors are in a device separate from a primary receiver that device that stores or renders the media stream.