Method, a computer program product, and a carrier for indicating one-way latency in a data network

• US 9,544,210 B2
• Filed: 03/01/2016
• Issued: 01/10/2017
• Est. Priority Date: 09/22/2004
• Status: Active Grant

• Current Assignee: Accedian Networks Inc. (Cisco Systems, Inc.)
• Original Assignee: Accedian Networks Inc. (Cisco Systems, Inc.)
• Inventors: Hansson, Kjell, Hagsand, Olof
• Primary Examiner(s): ONAMUTI, GBEMILEKE J
• Application Number:
  US15/057,224
• Publication Number:
  US 20160182332A1
• Time in Patent Office: 315 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 1/12 Synchronisation of different clock signals provided by a plurality of clock generators
• CPC Class Codes: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04J 3/0667 Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays arrangements for monitoring round trip delays in packet switching networks H04L43/0864
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04L 2212/00 Encapsulation of packets
• CPC Class Codes: H04L 43/067 using time frame reporting
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 43/0858 One way delays
• 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 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 7/10 Arrangements for initial synchronisation

Abstract

A method, a computer program product, and a carrier for indicating one-way latency in a data network (N) between a first node (A) and a second node (B), wherein the data network (N) lacks continuous clock synchronization, comprising: a pre-synchronization step, a measuring step, a post-synchronization step, an interpolation step, and generating a latency profile. The present invention also relates to a computer program product incorporating the method, a carrier comprising the computer program product, and a method for indicating server functionality based on the first aspect.

Claims

1. A method for determining one-way latency in a network comprising:

a requester node running a first process to transmit a first plurality of synchronization requests over a network to a responder node, the requester node comprising a first clock, the responder node comprising a second clock;

the requester node running a second process to receive a first plurality of synchronization responses from the responder node, each of the first plurality of synchronization responses being generated by the responder node in response to the responder node receiving one of the first plurality of synchronization requests, the first plurality of synchronization responses being used to determine a first smallest difference between the first clock and the second clock;

the requester node transmitting a plurality of measurement requests over the network to the responder node, the requester node storing latency data, the latency data comprising the transmit time for each of the plurality of measurement requests;

the requester node running a third process to transmit a second plurality of synchronization requests over a network to the responder node;

the requester node running a fourth process to receive a second plurality of synchronization responses from the responder node, each of the second plurality of synchronization responses being generated by the responder node in response to the responder node receiving one of the second plurality of synchronization requests, the second plurality of synchronization responses being used to determine a second smallest difference between the first clock and the second clock;

a processing node utilizing the first smallest difference between the first clock and the second clock, the latency data, and the second smallest difference between the first clock and the second clock to determine a rate of change in the difference between the clock rate of the first clock and the clock rate of the second clock, the processing node utilizing the rate of change to correct for clock latency in the latency data.

2. The method of claim 1, wherein the processing node is the requester node.

3. The method of claim 1, wherein the processing node is the responder node.

4. The method of claim 1, wherein the processing node is a server, the server coupled to the requester and the responder through the network.

5. The method of claim 1, wherein the first process and the third process are the same.

6. The method of claim 1, wherein the second process and the fourth process are the same.

7. The method of claim 1, wherein the first plurality of synchronization requests, first plurality of synchronization responses, the second plurality of synchronization requests, the second plurality of synchronization responses, and the plurality of measurement requests are encapsulated using the UDP/IP (User Datagram Protocol/Internet Protocol).

8. The method of claim 7, wherein the first plurality of synchronization requests, first plurality of synchronization responses, the second plurality of synchronization requests, the second plurality of synchronization responses, and the plurality of measurement requests are encoded using the RTP (Real Time Protocol).