# US 10,320,646 B2 · Apparatus and method to use PTP timestamps for two-way delay and delay variation measurement in IP networks

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- Number: US 10,320,646 B2
- Document ID: US10320646B2
- Status: Granted
- Kind: B2
- Application number: 14/641,141
- Filed: 2015-03-06
- Published: 2016-06-30
- Granted: 2019-06-11
- Earliest claimed: 2014-12-31
- Assignees: Telefonaktiebolaget LM Ericsson (publ)
- Applicants: Telefonaktiebolaget L M Ericsson (publ)
- Inventors: Gregory Mirsky; Ramanathan Lakshmikanthan
- Web page: https://patentgrep.com/patent/US10320646B2

## CPC

- H04L 43/106: using time related information in packets, e.g. by adding timestamps
- H04L 43/0852: Delays
- H04L 43/50: Testing arrangements
- H04L 67/141: Setup of application sessions (admission control or resource allocation in data switching networks H04L47/70)
- H04L 69/24: Negotiation of communication capabilities
- H04L 69/28: Timers or timing mechanisms used in protocols
- H04L 69/16: Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A method is implemented by a network device to establish a two-way active measurement protocol (TWAMP) test session that supports use of a Network Time Protocol (NTP) timestamp format and a Precision Time Protocol Version 2 (PTPv2) timestamp format. The network device acts as a server that communicates with a control-client to establish a TWAMP test session between a sender and a reflector. The method includes sending a server greeting message to the control-client indicating timestamp formats that the reflector can set, receiving a set-up-response message from the control-client indicating timestamp formats that the sender can interpret, checking whether the sender supports the multiple timestamp format extensions to TWAMP, configuring the reflector to set timestamps in a format that the reflector can set and the sender can interpret if the sender supports multiple timestamp format extensions to TWAMP, and sending a server-start message to the control-client.

## Claims

### Claim 1

A method implemented by a network device to establish a two-way active measurement protocol (TWAMP) test session that supports use of a Network Time Protocol (NTP) timestamp format and a Precision Time Protocol Version 2 (PTPv2) timestamp format, the network device acting as a control-client that communicates with a server to establish a TWAMP test session between a session-sender and a session-reflector, the method comprising:
opening a transmission control protocol (TCP) connection to the server;
receiving a server greeting message from the server, wherein the server greeting message includes an indication of whether the session-reflector is capable of setting timestamps in the NTP timestamp format and an indication of whether the session-reflector is capable of setting timestamps in the PTPv2 timestamp format, wherein the session-reflector supports multiple timestamp format extensions to TWAMP, and wherein the multiple timestamp format extensions to TWAMP include NTP timestamp format extension and PTPv2 timestamp format extension;
checking whether the session-reflector supports the multiple timestamp format extensions to TWAMP;
sending an extended set-up-response message to the server in response to determining that the session-reflector supports the multiple timestamp format extensions to TWAMP, wherein the extended set-up-response message includes an indication of a timestamp format that the session-reflector can set and the session-sender can interpret; and
receiving a server-start message from the server.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
sending a non-extended set-up-response message to the server in response to determining that the session-reflector does not support the multiple timestamp format extensions to TWAMP.

### Claim 3 (depends on 1)

The method of claim 1, wherein the extended set-up-response message indicates that the session-reflector can set and the session-sender can interpret both the NTP timestamp format and the PTPv2 timestamp format.

### Claim 4

A network device configured to establish a two-way active measurement protocol (TWAMP) test session that supports use of a Network Time Protocol (NTP) timestamp format and a Precision Time Protocol Version 2 (PTPv2) timestamp format, the network device configured to act as a control-client that communicates with a server to establish a TWAMP test session between a session-sender and a session-reflector, the network device comprising:
a non-transitory machine readable medium to store an extended active network performance measurement protocol component; and
a processor communicatively coupled to the non-transitory machine readable medium, the processor configured to execute the extended active network performance measurement protocol component, the extended active network performance measurement protocol component configured to:
open a transmission control protocol (TCP) connection to the server,
receive a server greeting message from the server, wherein the server greeting message includes an indication of whether the session-reflector is capable of setting timestamps in the NTP timestamp format and an indication of whether the session-reflector is capable of setting timestamps in the PTPv2 timestamp format, wherein the session-reflector supports multiple timestamp format extensions to TWAMP, and wherein the multiple timestamp format extensions to TWAMP include NTP timestamp format extension and PTPv2 timestamp format extension,
check whether the session-reflector supports the multiple timestamp format extensions to TWAMP,
send an extended set-up-response message to the server in response to determining that the session-reflector supports the multiple timestamp format extensions to TWAMP, wherein the extended set-up-response message includes an indication of a timestamp format that the session-reflector can set and the session-sender can interpret, and
receive a server-start message from the server.

### Claim 5

A computing device implementing a plurality of virtual machines for implementing network function virtualization (NFV), wherein a virtual machine from the plurality of virtual machines is configured to establish a two-way active measurement protocol (TWAMP) test session that supports use of a Network Time Protocol (NTP) timestamp format and a Precision Time Protocol Version 2 (PTPv2) timestamp format, the virtual machine configured to implement functionality that causes the computing device to act as a control-client that communicates with a server to establish a TWAMP test session between a session-sender and a session-reflector, the computing device comprising:
a storage medium having stored therein an extended active network performance measurement protocol component; and
a processor communicatively coupled to the storage medium, the processor configured to execute the virtual machine, where the virtual machine is configured to implement the extended active network performance measurement protocol component, wherein the extended active network performance measurement protocol component is configured to:
open a transmission control protocol (TCP) connection to the server,
receive a server greeting message from the server, wherein the server greeting message includes an indication of whether the session-reflector is capable of setting timestamps in the NTP timestamp format and an indication of whether the session-reflector is capable of setting timestamps in the PTPv2 timestamp format, wherein the session-reflector supports multiple timestamp format extensions to TWAMP, and wherein the multiple timestamp format extensions to TWAMP include NTP timestamp format extension and PTPv2 timestamp format extension,
check whether the session-reflector supports the multiple timestamp format extensions to TWAMP,
send an extended set-up-response message to the server in response to determining that the session-reflector supports the multiple timestamp format extensions to TWAMP, wherein the extended set-up-response message includes an indication of a timestamp format that the session-reflector can set and the session-sender can interpret, and
receive a server-start message from the server.

### Claim 6

A non-transitory machine readable storage medium having stored therein instructions to be executed by a network device to establish a two-way active measurement protocol (TWAMP) test session that supports use of a Network Time Protocol (NTP) timestamp format and a Precision Time Protocol Version 2 (PTPv2) timestamp format, the network device to act as a control-client that communicates with a server to establish a TWAMP test session between a session-sender and a session-reflector, the instructions when executed by the network device cause the network device to perform a set of operations comprising:
opening a transmission control protocol (TCP) connection to the server;
receiving a server greeting message from the server, wherein the server greeting message includes an indication of whether the session-reflector is capable of setting timestamps in the NTP timestamp format and an indication of whether the session-reflector is capable of setting timestamps in the PTPv2 timestamp format, wherein the session-reflector supports multiple timestamp format extensions to TWAMP, and wherein the multiple timestamp format extensions to TWAMP include NTP timestamp format extension and PTPv2 timestamp format extension;
checking whether the session-reflector supports the multiple timestamp format extensions to TWAMP;
sending an extended set-up-response message to the server in response to determining that the session-reflector supports the multiple timestamp format extensions to TWAMP, wherein the extended set-up-response message includes an indication of a timestamp format that the session-reflector can set and the session-sender can interpret; and
receiving a server-start message from the server.

### Claim 7 (depends on 6)

The non-transitory machine readable storage medium of claim 6, wherein the instructions when executed by the network device cause the network device to perform a further set of operations comprising:
sending a non-extended set-up-response message to the server in response to determining that the session-reflector does not support the multiple timestamp format extensions to TWAMP.

### Claim 8 (depends on 6)

The non-transitory machine readable storage medium of claim 6, wherein the set-up-response message indicates that the session-reflector can set and the session-sender can interpret both the NTP timestamp format and the PTPv2 timestamp format.