Question about running multiple congestion control algorithms at the same time

[BobAnkh]

About running multiple algorithms at the same time, I have read #85, but I wonder if there is an easier way for me to perform multiple emulation experiments at the same time without modifying the source code?

Algorithms implemented use args like --ipc netlink, does it mean that I cannot run multiple ccp_kernel to perform multiple CCAs at the same time?

Or which file in source code should I modify to support this feature?

[akshayknarayan]

You are correct that you cannot run multiple instances of ccp_kernel. ccp_kernel is a kernel module that provides (from the kernel's perspective) a congestion control implementation.

There is, however, RunBuilder. Using additional_alg() (https://docs.rs/portus/0.6.1/portus/struct.RunBuilder.html#method.additional_alg), it is possible to register other cc implementations and run them according to the "alg" parameter in the create message: https://github.com/ccp-project/portus/blob/master/src/run.rs#L602.

For ccp-kernel specifically, this field is hard-coded: https://github.com/ccp-project/ccp-kernel/blob/master/tcp_ccp.c#L329. If you have a specific way to assign congestion control algorithms to flows already, then you have two options:

1. You could modify ccp-kernel to pass the name of a congestion control algorithm to ccp, and register those algorithms with the above additional_alg() method.
2. You could write a CCA implementation that calls into other algorithms' implementations from the new_flow() method: https://docs.rs/portus/0.6.1/portus/trait.CongAlg.html#tymethod.new_flow. This method gets the following information about the flow: https://docs.rs/portus/0.6.1/portus/struct.DatapathInfo.html which you could use to instantiate a CCA's flow type accordingly.

[BobAnkh]

Ok, many thanks for your kind help and detailed guidance @akshayknarayan . I will try to see if I can do this later.