Method and apparatus for performance monitoring in electronic communications networks

• US 5,793,976 A
• Filed: 04/01/1996
• Issued: 08/11/1998
• Est. Priority Date: 04/01/1996
• Status: Expired due to Term

• Current Assignee: Verizon Laboratories Incorporated (Verizon Communications Inc.)
• Original Assignee: GTE Laboratories Incorporated (Lumen Technologies, Inc.)
• Inventors: Chen, Thomas M., Liu, Stephen S.
• Primary Examiner(s): Voeltz, Emanuel Todd
• Assistant Examiner(s): PEESO, THOMAS R
• Application Number:
  US08/625,102
• Time in Patent Office: 862 Days
• Field of Search: 364/550, 364/551.01, 395/200.11, 395/200.01, 395/200.54, 370/351, 370/352, 370/353, 370/355, 370/389, 370/458
• US Class Current: 709/224
• CPC Class Codes: H04L 2012/5619 Network Node Interface, e.g. tandem connections, transit switching
• CPC Class Codes: H04L 2012/5625 Operations, administration and maintenance [OAM]
• CPC Class Codes: H04L 2012/5652 Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04L 49/205 Quality of Service based
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags

Abstract

Management packets are defined that are modified in the payload by each node along a virtual connection and are used to measure both end-to-end QoS and specific individual intermediate node performance parameters. Management packets are implemented by defining entirely new packets or by modifying ATM OAM cells. Switches or routers for use as intermediate nodes are defined that modify the payload of the management packet and locally measure packet delay and packet loss. An intermediate node measures and records the difference between the arrival and departure times of management packets at that switch utilizing delay-stamp fields within the management packets and either the switch internal routing header or timestamp fields within the packet. At the endpoint of the virtual connection, delay-stamp fields in the management packet indicate individual node delays and the cumulative delay. An intermediate node counts the number of packets it discards and records these values in the payload of the management packet individually and cumulatively.

Claims

1. A method for performance monitoring in an electronic communications network having at least one network connection, each of said network connections having a network connection originating endpoint, a network connection destination endpoint, and at least one network connection intermediate node, comprising, in combination, the steps of:

creating at least one management data packet, each of said management data packets comprising a header and a payload data field, each of said management data packets further comprising, in combination;

routing header means, said routing header means being part of said management data packet header;

packet function field, said packet function field being part of either said management data packet header or said management data packet payload data field; and

at least one payload local performance monitoring field, said payload local performance monitoring field being part of said management data packet payload data field;

inserting at least one of said management data packets into a stream of user data packets at one of said network connection originating endpoints;

measuring at least one performance monitoring parameter at each of said network connection intermediate nodes;

for each of said management data packets, recording, at each of said network connection intermediate nodes while maintaining the position of said management data packet in the packet datastream, in one of said payload local performance monitoring fields in said management data packet, said performance monitoring parameter measured at said network connection intermediate node; and

extracting the values in said payload local performance monitoring fields after said management data packet reaches said network connection destination endpoint.

2. The method of claim 1, further comprising the steps, in combination, of:

including in said payload local performance monitoring fields at least one payload delay-stamp field, initialized to a predetermined value;

detecting entry of each of said management data packets into any of said network connection intermediate nodes;

for each of said management data packets and said network connection intermediate nodes, recording the time of entry of said management data packet into said network connection intermediate node;

detecting the imminent exit of said management data packet from said network connection intermediate node;

comparing the time of said imminent exit of said management data packet to said recorded time of entry; and

incrementing, at said network connection intermediate node while maintaining the position of said management data packet in the packet datastream, the value in one of said payload delay-stamp fields by the difference between said time of entry and said time of exit.

3. The method of claim 2, further including the step of adding the values in all said incremented ones of said payload delay-stamp fields of said management data packet, in order to get a total accumulated delay value, when said management data packet reaches said network connection destination endpoint.

4. The method of claim 1, wherein each of said management data packets further include a packet type field, identifying to said network connection intermediate nodes and said network connection destination endpoint that said data packet is a management data packet.

5. The method of claim 1, wherein said routing header means of each of said management data packets contains a field identifying to said network connection intermediate nodes and said network connection destination endpoint that said data packet is a management data packet.

6. The method of claim 2, further including the steps, in combination, of:

including in said payload local performance monitoring fields at least one payload timestamp field; and

for each of said delay management packets, recording, at said network connection intermediate node while maintaining the position of said management data packet in the packet datastream, into one of said payload timestamp fields, the time of entry of said management packet into said network connection intermediate node.

7. The method of claim 6, further including the step of adding the values in all said incremented ones of said payload delay-stamp fields of said management packet, in order to get a total accumulated delay value, when said management packet reaches said network connection destination endpoint.

8. The method of claim 6, further including the step of recording, at said network connection intermediate node while maintaining the position of said management data packet in the packet datastream, said time of imminent exit in an unused one of said payload timestamp fields of said delay management packet.

9. The method of claim 8, further comprising the step of comparing each of said payload timestamp fields containing said times of entry of said delay management packet into each of said network connection intermediate nodes to the corresponding one of said payload timestamp fields containing said time of imminent exit from said network connection intermediate node in order to obtain a delay value for each of said network connection intermediate nodes.

10. The method of claim 2, wherein said time of entry of said management packet into said network connection intermediate node is recorded in an internal routing header created at said network connection intermediate node and attached to said management packet while in said network connection intermediate node.

11. The method of claim 10, further including the step of adding the values in all said incremented ones of said payload delay-stamp fields of said management packet, in order to get a total accumulated delay value, when said management packet reaches said network connection destination endpoint.

12. The method of claim 1, further comprising the steps, in combination, of:

including in said payload local performance monitoring fields at least one payload discarded packet count field, initialized to a predetermined value;

counting at each of said network connection intermediate nodes the number of said user data packets that are discarded by said network connection intermediate node between the departure of an immediately previous one of said management data packets and the departure of a current one of said management data packets; and

incrementing, at said network connection intermediate node while maintaining the position of said management data packet in the packet datastream, the value in one of said payload discarded packet count fields of said current one of said management data packets by said discarded number of said user data packets.

13. The method of claim 12, further comprising the step of adding the values in all said incremented ones of said payload discarded packet count fields of said management data packet, in order to get a total accumulated discarded user packet value, when said management data packet reaches said network connection destination endpoint.

14. The method of claim 2, further comprising the steps, in combination, of:

including in said payload local performance monitoring fields at least one payload discarded packet count field, initialized to a predetermined value;

counting at each of said network connection intermediate nodes the number of said user data packets that are discarded by said network connection intermediate node between the departure of an immediately previous one of said management data packets and the departure of a current one of said management data packets; and

incrementing, at said network connection intermediate node while maintaining the position of said management data packet in the packet datastream, the value in one of said payload discarded packet count fields of said current one of said management data packets by said discarded number of said user data packets.

15. The method of claim 14, further comprising the step of adding the values in all said incremented ones of said payload discarded packet count fields of said management data packet, in order to get a total accumulated discarded user packet value, when said management data packet reaches said network connection destination endpoint.

16. The method of claim 15, further comprising the step of adding the values in all said incremented ones of said payload delay-stamp fields of said management data packet, in order to get a total accumulated delay value, when said management data packet reaches said network connection destination endpoint.

17. A router for use in an electronic communications network comprising, in combination:

at least one input for receiving data packets from at least one network connection;

at least one output for relaying data packets to one of said network connections;

means for detection of entry of a management packet into said router, said management packet being comprised of at least a header field and a payload field;

means for associatively recording the time of entry of said management packet into said router, wherein said means for associatively recording said time of entry records said time of entry in a payload timestamp field in the payload field of said management packet;

means for detection of the imminent exit of said management packet from said router; and

means for recording, at said router, a parameter into the payload field of said management packet that can be used to obtain the delay incurred by said management packet in said router.

18. The router of claim 17, further including means for recording, at said router, said time of imminent exit of said management packet from said router into the payload field of said management packet.

19. A performance-monitored switching mechanism for concurrently routing each of a plurality of data packets in a datastream, each of said data packets comprising a header and a payload, to a selected one of plural output data pathways in accordance with a destination address, said mechanism comprising, in combination:

a plurality of input ports for concurrently receiving said data packets;

a plurality of output data pathways;

switching means connected between said input ports and said output data pathways; and

means for modifying said payload of one of said data packets without said modified data packet losing its position in said datastream of said data packets, wherein said means for modifying said payload of one of said data packets further comprises, in combination;

means for selecting one of said data packets in said datastream to be modified in said payload;

means for writing data to said payload of said selected data packet; and

means for performing dummy writes to non-selected ones of said data packets in said datastream.