Re: [RTnet-developers] can I use netem on rtnet?

[Jan K. <jan...@we...>]

Li Chanjuan wrote:
> hi,jan:
>     
>     I want to do a experiment on rtnet using netem and want to know that
> how rtnet works when transmission error occurs. but after I setup rtnet,
> I use:
>   #tc qdisc add dev rteth0 root netem delay 1ms
> there is error message: can't find "rteth0" device.
> I use strace to find what happened, I got:
> 
> ioctl(4,SIOCGIFINDEX,{ifr_name="rteth0",..}) =-1(No such device)
> 
> I think this because rtnet is invisible to Linux, so tc can not work.

Exactly.

> 
> Is it possible to use netem on rtnet? if it is, what should I do?

Nope, there is no (publicly known) implementation of a netem-like
service on top of RTnet. However, it shouldn't be too tricky to write
such support on top of RTnet's socket API.

On the other hand, I wonder why you need hard real-time guarantees for a
"noise generator" like netem? Why is Linux itself unsuited?

Jan