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rate based satellite control protocol

Anyone have much experience with this. This is faily new feature in 12.3t/12.4

I am not looking to use this on satellite but to solve the issue of latency and tcp window size.

We have another of our standard arguemnts with the users that we need to put in bigger links because it takes too long to transfer 10g files from some remote location.

They don't seem to want to hear that the lines are not even close to 100% used and the problem is that the TCP stack in their system need to be tuned and even then they can't use 100% because of the latency due to distance.

We are hoping to get them to split the file and transfer in parrell with the argument that if their application fails that they don't have to retransmit the whole file. Just telling them to split the file for network reasons isn't working.

So far I have found little on cisco's site about using this feature.

It appears there are 2 options to help with prohlems like this.

tunnel rbscp window_stuff

tunnel rbscp ack_split

Any opinions on which is better to trick a user machine into sending data faster.

The ack_split option appears to send ack packets to the source machine for packets the destination machine actually has not told the router yet it has received.

The windowstuff option just appears to increase the window size and buffer the data at the remote site.

The issue I can see with the ack_split its that the router has told the local machine that the far end machine has received data it has not. If the remote machine would lose a packet tcp recovery and retransmission will be a issue. Unless the router keeps the packets the only option is to reset the connection since there is no way to get the local machine to resend a packet it has a ack for. I can find no reference as to how the ack_split handles this.

Since the router buffers the packets in the windowstuff option recovery from a packet loss looks better but does this option still suffer from maximum tcp window size. Even with the tcp window size set to the maximum latency on some lines will limit the transfer before bandwidth goes to 100%. If the users would really have their tcpwindow already at the maximum then this option would have little effect.

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