World Community Grid - View Thread - BOINC: When there are internet bandwidth concerns for one or more clients.

At times members ask for tweaks and hacks to get qualified for participating in the more internet bandwidth demanding researches on the grid. Particularly when the local ISP speed is limited or the servers are very busy will the repeated transmission retrying by the client lead to a gradual degradation of download speed that BOINC records, especially when those task files are small. Also uploading large result files can affect the effective speed of downloading, which is the critical value that the servers record for each host.

There are a number of controls to mitigate the negative effect on downloading during uploads:

1) In the website device profiles, so these restrictions work for all devices the same way

or

2) In the advanced preferences as can be changed in the BOINC Manager.

3) Changing the default values of the number of concurrent files that are allowed to be up and downloaded.

On points 1/2, by limiting the upload speed total per the red squared box in screenshot below, showing the local preferences of the 6.10.58 client. No matter how many concurrent files are transferred, the total is here not allowed to exceed 128KB. The download value can be set to zero, which means unrestricted. Limiting the upload rate generally has a positive impact on the effective rate that BOINC records for the download rate.

On point 3, by setting the 2 file tranmission maxima, overall and per-project, the transmission speed can be distributed to more or less than the default 2

<max_file_xfers>N</max_file_xfers>
    Desc: Maximum number of simultaneous file transfers (default 8). 
<max_file_xfers_per_project>N</max_file_xfers_per_project>
    Desc: Maximum number of simultaneous file transfers per project (default 2).

In the above two controls replace the value N with that found to best fit the individual conditions. Here 1 is not recommended as when a large file transfer takes place, all others are blocked. Noting that the client has to be restarted opposed to what the manual suggests. Does not work for all <options> to make them effective.

There are other solutions such as those for multiple device owners. These hosts have no knowledge of each other i.e. they run entirely oblivious of what other clients do, that communicate over the same internet connection. When they transmit simultaneously, again the effective throughput as recorded by BOINC will deteriorate. When bandwidth resources are limited consider then to use BOINC scheduled networking function, each device getting a different time slot in the day and increasing the additional buffer to a size that will bridge the period that the client is not allowed to communicate with the servers.

Some members will be encountering traffic throttling by their ISP (Internet Service Provider), whole or part of day. The client has for that facility to limit the amount of daily traffic with the "Traffic at most , every ...) function and also a scheduler that allows to set the overall and daily time exceptions when to network. With that and the cache/additional work buffer option setting, all on the same Network preferences screen extended control is possible to meet requirements.

Experimentation is needed as is a longer period of observation to find best settings.

Related topics:
Sample scenarios when to crunch or communicate with servers
Client Configuration with "cc_config.xml"

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