TWAMP protocol
1. Introduction
Tow-Way Active Measurement Pootocol (TWAMP) is an open protocol for measuring network performance between any tow devices in a network that supports the protocols in the TWAMP framework. It is a standard protocol framework that separates sessions based on the client/server architecture. The TWAMP client is a host that initiates the TCP connection and acts as a control-client and a session-sender, while the TWAMP server is a host that acknowledges the TCP connection and performs the roles of a server and a session-reflector. TWAMP-Control messages are exchanged between the control-client and the server and TWAMP-Control messages are exchanged between the control-client and the server and TWAMP-Control messages are exchanged between the session-sender and the session-reflector. Four different TWAMP devices can perform the four logical roles of TWAMP control-client, server, session-sender, and session-reflector.
2 TWAMP Overview
2. 1 TWAMP Architecture
(1) Control-Client: An end system that initiates requests for TWAMP-Test sessions, triggers the start and temination of a set of sessions.
(2)Server: An end system that meanages one or more TWAMP-Test sessions, is capable of configuring per-session state in session endpoints, and returns the results of a test session.
(3)Session-Sender: The sending endpoint of an TWAMP-Test session.
(4)Session-Relflector: The receiving endpoint of an TWAMP-Test session.
An example of possible relationship scenarios between these roles is presented below. In this example, different logical roles are played on different hosts. Unlabeled links in the figure are unspecified by this document and may be proprietary protocols.
Figure 1: Four Elements of TWAMP
TWAMP-Control is used to initiate, start and stop test sessions between Control-Client and Server.
TWAMP-Test is used to exchange test packets between Session-Sender and Session-Reflector.
Figure 2: TWAMP Typical Scenario
2.2.2 TWAMP Workflow
Figure 3: WTAMP Workflow
3 Control Packet format
3.1 Server Greeting
3.2 Set-Up-Response packet format
3.3 Server Start packet format
3.4 Request TW-Session packet format
3.5 Accept Session packet format
3.6 Start ACK packet format
3.7 Stop Session packet format
Figure 10: Stop Session packet format
4 TWAMP-Test Packet Format
4.1 Sender-test packet format
4.2 Reflector test packet format
