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Path measurement: Difference between revisions
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== Configuration PCAP measurement == | == Configuration PCAP measurement == | ||
[[File:Path-measurement-pcap-settings.png|border|660x660px]] | |||
Since firmware version 3.7, the path measurement can also be done based on two capture files created from two different network locations. The separate configuration tab "Configuration PCAP Analysis" allows to select two files from attached storage devices. | |||
The settings are similar to the live measurement. VLG filter can be applied to both files, but an option also allows to disable the use of the configured virtual link groups, or use separate groups for each file. In contrast to live mode, a VLG does not need to be used to differentiate traffic since it is clear from the selected file which one is the primary traffic and which one is the client traffic. But of course VLG can be used to filter out traffic that should not be part of the analysis. | |||
The "Measurement settings" contains all settings from the live measurement plus three options only applicable in PCAP mode. | |||
* Virtual link group mode: Select to either use: | |||
** Use global VLG settings: Use the VLG configuration configured globally on this device. | |||
** Use separate VLG per file: Create a temporary VLG for each file so all statistics can be accessed for each individual file regardless of the configuration of the regular virtual link groups. | |||
** Disable use of VLGs: Disable all VLG configurations and use one common view of all data. | |||
* Run analysis in main memory: The analysis requires a relatively large amount of memory depending on the setting values for packet delay and packet rate. In live mode, this data is always kept in main memory for performance reasons, but in PCAP mode the data is stored on a local storage device by default. This is slower but does not require a lot of additional memory reserved, especially when parallel pcap analysis is enabled. | |||
* Storage device to use: If a storage device is available, the first one is selected by default. Otherwise the system disc is used to store the packet comparison information. The approximate amount of storage space required is shown below the selection box. | |||
<u>IMPORTANT NOTE:</u> The configuration values for packet rate and packet delay can be adjusted to reflect the actual parameters of the given PCAP files. The values are in relation to packet time of the PCAP files, not real time. So the packet rate does not correlate with the actual processing speed (which might be higher or lower than the packet rate within the PCAP files). The packet rate should be adjusted if the debug value "Packets processed too early" is non-zero. The default packet delay is set to 1 second to reduce the amount of memory required but should be adjusted to the expected maximum delay within the PCAP recording. | |||
== Measurement statistics == | == Measurement statistics == | ||
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If the measurement connection is stopped or stopped working for other reasons (remote device unavailable, etc), the status box will turn red and a button appears to reconnect to the remote device. | If the measurement connection is stopped or stopped working for other reasons (remote device unavailable, etc), the status box will turn red and a button appears to reconnect to the remote device. | ||
If the reconnect fails, an error message appears with detailed information what was going wrong. | If the reconnect fails, an error message appears with detailed information what was going wrong. | ||
''' Typical errors are:''' | ''' Typical errors are:''' | ||
*remote device inaccessible (are the IP and port settings correct?) | *remote device inaccessible (are the IP and port settings correct?) | ||
* authentication error (invalid credentials?) When both boxes are green, the measurement is running and the four graphs show the real-time results. | * authentication error (invalid credentials?) When both boxes are green, the measurement is running and the four graphs show the real-time results. | ||
* Insufficient memory: Usually may only appear in PCAP analysis mode indicating that the values for packet delay and packet rate are too large. Either reduce the values or use a larger storage devices capable of storing the required data (amount shown in the configuration section) | |||
=== Two-Way-Latency === | === Two-Way-Latency === | ||