what is the relaitionship among the OpenFlow/datapath ,OpenFlow/udatapath and OpenFlow/Swtich in NS3 OpenFlow module?

[南宫煌]

Now I am reading the source code of NS3 OpenFlow module ,I found that there are many same file in OpenFlow/datapath ,OpenFlow/udatapath and OpenFlow/Swtich.

Which one is the realization of  Switch ?

Thank you!

[Tommaso Pecorella]

Hi,

sorry but I can't find what you are referring to. Mind to be more precise ? I.e., file name, class name, etc.

Thanks,

T.

[南宫煌]

As well known,SDN networks is combined with controller、switch and host. 

Now I am reading the source code of OpenFlow module in NS3,I found that there are many same files in OpenFlow/datapath ,OpenFlow/udatapath and OpenFlow/Swtich directory, as bellow pictures. 

What are these directory used for? Which one is used as switch? What is the  difference between datapath and switch directory? and then datapath and udatapath.

   

 

[Tommaso Pecorella]

I know what's an SDN and I believe that the "SDN" term is used much like an empty keyword by too many people, exactly like "WSN". And I know I'd really like to have 1 dollar for each time an imbecile has used the term "SDN" in an inappropriate or meaningless way.

About your question, that's not the ns-3 openflow module. That is the OpenFlow ns-3 fork "fixed" to be used together with the ns-3 OpenFlow module.

The difference is that the thing you're looking at is practically identical to the original OpenFlow code. As a result, I'd suggest to check the OpenFlow code documentation (there are some links in the README).

As a side and totally unrelated note, I do remember that once upon a time the SysOp (the Admin) was used to post messages in forums with a title like "Sex pictures links".

Usually the content wasn't about sex pics, of course. It was about the forum rules or important announcements.

That's because people are lazy as **** and they don't even care to open something that seems important, like files named "Warning", "Important", "ReadMe" or "Install".

Speaking of, there's an "INSTALL" file in that directory... and guess what you can find inside (at the very beginning, not even the hassle to read the whole file) ?

The OpenFlow reference implementation includes three separate

OpenFlow switch implementations:

        - The "userspace switch": This implements an OpenFlow switch

          as a single user program (built as switch/switch).  The

          userspace switch is the easiest to build and use but it is

          much less featureful than the other switch implementations.

        - The "kernel-based switch": This divides the switch into a

          "datapath" Linux kernel module (openflow_mod.o for Linux 2.4

          or openflow_mod.ko for Linux 2.6) and a userspace program

          (secchan).  The kernel-based switch is faster than either of

          the other two implementations but requires building and

          installing a kernel module, which can sometimes be

          challenging.

        - The "userspace datapath-based switch": This divides the

          switch into a userspace "datapath" (built as

          udatapath/udatapath) and the same userspace program used by

          the kernel-based switch (secchan).  The userspace

          datapath-based switch is as featureful as the kernel-based

          switch and it does not require building a kernel module, but

          it is not as fast as the kernel-based switch and it is part

          of the OpenFlow extensions distribution, not the main

          OpenFlow distribution.

T.

[南宫煌]

Thank you for your answer and that vivid instance.

I got the answer for my question and the way to learn things .

By the way,SDN is meant for "Software Defined Networks" which is a novel network architecture .