TCP Network Metrics

When the agent collects data, it considers each TCP socket connection separately. The data is then consolidated by <server-ip,server port>, where server-ip and server-port are the IP address and TCP port number of the remote computer that the agent computer has communicated with.

Parameter	Description
Number of Connections	The number of received TCP packets that have the SYN flag set and contain no data bytes, that is, the server’s replies to new connection requests.
Number of retransmissions	PerformanceGuard counts the number of retransmitted network packages, that is every time the client sends a packet that contains data that has previously been sent, PerformanceGuard will increment the number of retransmissions. ⚠️ When using the Wireshark tcp.anaylsis.retransmission filter, Wireshark only counts the first of a series of retransmitted packets. For example, if the device has three outstanding packages, and the retransmission counter expires, Wireshark will count this as a single retransmission while PerformanceGuard will count three retransmitted packets. This means that PerformanceGuard will show a higher number of retransmissions than Wireshark. The difference between the retransmission count reported by Wireshark and PerformanceGuard will vary depending on the TCP window size at the time that the retransmission occurs. You should also be aware that when you apply the tcp.analysis.retransmission filter in Wireshark, Wireshark will show packets that look like they have been retransmitted both by the client on which the measurement has been made, but also packets originating from the other end of the TCP connection. You may want to combine the tcp.analysis.retransmission filter with an ip.src.== <client> filter in order to only see transmitted packets.
Number of connection resets	The number of packets with the TCP RST flag set. Sent as well as received packets are counted.
Send Packets	The number of sent packets that contains TCP data.
Send Bytes	The number of data bytes contained in the sent TCP packets.
Send Trains	A send train is counted when a packet that contains TCP data is sent, and the previous packet that contained TCP data was received, or the packet is the first one with data sent on the connection. For more information about trains, see TCP IP.
Received Packets	The number of received packets that contains TCP data.
Received Bytes	The number of data bytes contained in the received TCP packets.
Received Trains	A received train is counted when a packet that contains TCP data is received, and the previous packet that contained TCP data was sent.
Total Response time	Whenever the received train counter is incremented, a response time is calculated as the time from the first packet of the previous send train (sent by the client) to the first packet of the new received train (received from the server). This time is the individual response time for a single request. The sum of these individual response times is the Total Response Time.
Response time histogram H0-H8 slots	Each slot contains a count of how many individual response times have fallen within the corresponding interval. The intervals are set by the Responsetime Histogram Intervals parameter on the Frontend tab under ADMINISTRATION → Setup → Parameters, and apply to all configuration groups. The default value is 10,20,50,100,200,500,1000,2000,500000, which gives these intervals in milliseconds: H0: 0-10 H1: 10-20 H2: 20-50 H3: 50-100 H4: 100-200 H5: 200-500 H6: 500-1000 H7: 1000-2000 H8: more than 2000
Response time histogram H9 slot	A count of the requests for which the agent didn’t receive a response train within the time set by the agent’s AbsResponseTimeout value. The default is 500 seconds. See Agent Registry Keys.