TWAMP for Client and Server with SNMP
Overview
The Two-Way Active Measurement Protocol (TWAMP) provides a standardized method for actively measuring IP network performance. It designed to evaluate metrics such as latency, jitter, and packet loss in a controlled, repeatable manner. By leveraging a client-server model, TWAMP delivers bidirectional insights that help validate service levels and troubleshoot issues proactively.
TWAMP sessions are initiated by a client, which sends control and test packets to a server (also called a reflector). The server, in turn, responds to these probes, allowing the client to calculate round-trip performance statistics.
TWAMP Client
The TWAMP client acts as the test originator. It’s responsible for setting up control connections, launching measurement sessions, and collecting performance data. Each session defines sender and receiver addresses, ports, and various probe parameters, such as packet count and interval timing.
Client Feature Characteristics
Feature characteristics of the client include:
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Initiating multiple test sessions across different server addresses. |
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Supporting both IPv4 and IPv6 traffic. |
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Defining control parameters such as sender/receiver ports and DSCP markings. |
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Starting and stopping sessions based on test scenarios. |
TWAMP Server
The TWAMP server in OcNOS operates as a reflector. It listens for incoming control connections from external TWAMP clients and responds to test packets once a session is active. The server tracks connection and session details throughout the lifecycle of each test.
You can configure the server to enforce limits on active connections, sessions per connection, and per-client usage. It also supports session inactivity timeouts. By using the listen-vrf option, you can enable the server to operate across multiple VRFs, allowing performance measurements in segmented routing environments.
OcNOS version 6.1.0adds SNMP integration, allowing external systems to monitor TWAMP server activity in real time.
Server Feature Characteristics
Feature characteristics of the server include:
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Accepts TWAMP control connections and test sessions without initiating communication. |
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Supports multiple VRFs using listen-vrf, allowing measurement across isolated routing domains. |
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Configurable Resource Limits: |
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Maximum number of concurrent connections |
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Maximum sessions per connection |
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Per-client session and connection limits |
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Session inactivity timeouts |
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Allows configuration of the listening port (default 862, configurable within the TCP dynamic port range). |
SNMP for TWAMP
OcNOS version 6.1.0introduces the SNMP feature provides real-time visibility into TWAMP activity through trap notifications and MIB access. You can monitor events such as session starts, client timeouts, and threshold violations using standard SNMP tools.
SNMP Feature Characteristics
Feature characteristics of the SNMP include:
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snmpget and snmpwalk queries for TWAMP server data. |
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SNMPv2-style traps for key operational events. |
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NETCONF-based notifications for dynamic state changes. |
Examples of trap-triggering events:
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A client establishing or disconnecting from a session. |
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A session reaching its configured timeout. |
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The server hitting its maximum connection or session limits. |
All SNMP events follow a structured OID scheme under the IP Infusion enterprise MIB tree (.1.3.6.1.4.1.36673), ensuring compatibility with centralized network monitoring systems.
Benefits
The TWAMP Client Implementation has following benefits to network management and optimization:
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TWAMP clients adhere to standardized protocols, ensuring compatibility and interoperability with various TWAMP servers. |
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SNMP traps provide immediate visibility into session events and performance issues. |
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Automatic trap generation for connection limits, timeouts, and session states. |
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Provides flexible deployment across virtual routing domains. |
Prerequisites
Ensure that the TWAMP client has a stable and reliable network connection to the TWAMP server.
Topology
The network topology includes the interactions between TWAMP Server and TWAMP Client entities, highlighting the flow of control messages and test packets. The TWAMP Client initiates active measurement sessions by sending control messages to the TWAMP Server over the TWAMP Control Connection. The TWAMP Server, in response, configures the session and directs test packets to the TWAMP Session-Reflector, which ensures proper routing and measurement. The results of these measurements are then relayed back to the TWAMP Client for analysis.
The following diagram example shows 2 nodes connected by a physical link through interfaces xe14 on each end. We will configure the first node as a TWAMP client. The second node must have a TWAMP server running.
Figure 192. TWAMP Client-Server
In the below example configurations, configure the Client for IPv4 and then for IPv6.