BITS Functionality – Common Misconception

It is commonly thought that BITS can help with WAN bandwidth problems. However BITS in its current version is only aware of local interfaces. Long story short it can only see the Ethernet connection of the client not the WAN interface. Remember it was originally designed for dial up.

•Supports resumption of file transfers
•Current version does not work well over WAN links
•From the platform SDK:
“BITS is only aware of the network conditions on the client computer; BITS is not aware of network conditions beyond the client. If there are no applications running on the client that use the network, BITS consumes most of the available bandwidth. This does not mean the network beyond the client is idle; the network may be at full capacity.
If the client has a fast network card (10 Mbps) but is connected to the network via a slow link (56 Kbps), BITS will compete for the full bandwidth instead of using only the available bandwidth on the slow link. This is because BITS has no visibility of the network traffic beyond the client.”
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/bits/bits/network_bandwidth.asp?frame=true
•BITS is configurable via GPO for greater control if necessary

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