Performance
The MTP/IP networking technology that transports data for ExpeDat is designed to adapt to a wide variety of network circumstances. The default settings will allow you to use the full available resources of your network while still being fair to other traffic.
If you have specific performance requirements, or suspect that some of your network components may be misbehaving or overloaded, this section will help you to adjust ExpeDat performance to your needs. You may also wish to refer to DEI Technical Note 0005 for general information about MTP/IP bandwidth management features.
Network Limitations
Most Wide Area Network paths involve hundreds of different components, any one of which may be limiting your available bandwidth. Here are a few of the more common types to consider:
ExpeDat cannot move data faster than the slowest of these capacities. So if performance is not meeting your expectations, check your systems for the types of limitations listed above. DEI Technical Note 0003 offers detailed advice on testing and finding network limitations.
Moving Data Even Faster
Normally MTP/IP makes an effort to allow other traffic on the network a fair share of available resources. If you want your ExpeDat data flows to achieve the absolute maximum speed, regardless of other users, you may do so by increasing the "aggression" of MTP/IP.
Aggression is a value between -3 and +5 which determines how hard MTP/IP presses the limits of the underlying network hardware. Default values are in the range of 0 to 2 (depending on your license configuration) and try to strike a balance between speed and fairness. Setting a higher aggression level of 3, 4, or 5 may improve ExpeDat throughput, but it may also be disruptive to other users of the network.
Aggression level 5 should be used if your entire network path fully supports large UDP datagrams (over 1500 bytes). For example, if you are operating on a gigabit or faster ethernet LAN and have Jumbo MTU enabled, you may find that level 5 allows you to fully utilize the network while reducing your CPU load. However, if any component of the path does not properly implement IP fragmentation standards, this level of aggression may cause severe performance degradation or even a loss of connectivity. Certain high-security encryption and VPN devices are known to misbehave in this way. You should carefully test aggression settings above 2 prior to deployment.
You can set aggression in the servedat command line, servedat configuration file, movedat command line, movedat configuration file, or MTPexpedat configuration file.
Moving Data Slower
For shared network environments, you may wish to limit ExpeDat's impact on other users even more than the default settings.
The most flexible way to give priority to other users is to reduce the aggression level described above. Values below 2 will limit the resources MTP/IP is willing to use, leaving more resources for other traffic flows. Note that on networks with inherently high-latency or packet loss (such as satellite or packet radio), lower aggression may reduce performance even when there is no other traffic.
You can also set a specific bandwidth limit for ExpeDat. The MaxRate setting establishes a ceiling for both individual transactions and the program as a whole. If your data path has a fixed known capacity, you can set MaxRate to a value less than that to apportion the bandwidth between ExpeDat and other users. You can even combine this with increased aggression to make ExpeDat use exactly that amount of bandwidth.
If you have applications on your network which are sensitive to latency issues, such as voice or video over IP, you can set a specific latency ceiling for ExpeDat. The MaxRTT setting will cause MTP/IP to slow down whenever it observes latency above the given value.
Refer to the links above for details on how to set these values. Also see DEI Technical Note 0005 for general information about MTP/IP bandwidth management features.