About agent-based measurement tests

Four test types

CNA provides four tests for agent-based measurement:

• Real Time Protocol (RTP) is used for media streams such as voice, audio, and video that have a time-dependent relationship between packets. The RTP test echoes a media stream between two endpoints. An RTP test measures the following variables:
• Delay--How long (in milliseconds one-way) it takes the UDP packet stream to reach its destination.
• Jitter--Unevenness in packet delay (in milliseconds).
• Loss--Percentage of packets lost in transit.
• Inter Arrival Time--Time between receipt of successive test results from a specific subzone combination (cell). For example, if the test rate is 60 tests per minute, and the zone hierarchy has 60 cells, each cell should report one test result per minute. IAT should be 60 seconds. A longer IAT may indicate a network problem or an unresponsive CNA server or agent.
• Ping or echo-check is used to establish connectivity and measure basic connection characteristics between two endpoints. A Ping test measures the following variables:
• RTT (Round Trip Time) in milliseconds (ICMP both directions).
• Loss--Percentage of packets lost in transit.
• Inter Arrival Time--Time between receipt of successive test results from a specific subzone combination (cell).
• Traceroute collects routing information by identifying each node in succession until the destination is reached. A traceroute test measures the following variables:
• Hop RTT--Round Trip Time (RTT) in milliseconds for each hop along the route (UDP outbound and ICMP inbound).
• Inter Arrival Time--Time between receipt of successive test results from a specific subzone combination (cell).
• Transmission Control Protocol (TCP) Connect is used for media streams that do not have a time dependent relationship, but that must be transmitted accurately, typically data streams. A TCP test measures the following variables:
• Cerror--Connection success or failure.
• Delay--How long (in milliseconds) the connection takes to complete.
• Inter Arrival Time--Time between receipt of successive test results from a specific subzone combination (cell).