[Ns-developers] NS-3 promiscuous mode for NetDevice

[Mathieu Lacage]

On Tue, 2008-07-01 at 00:08 +0100, Gustavo Carneiro wrote:

> Regarding promiscuous mode vs monitor mode, it's almost, but not
> quite, just a matter of terminology.  I think that in monitor mode the
> netdevice captures and records 802.11 control frames as packets.
> Promiscuous mode is less demanding, as it only captures data frames,
> regardless of source/destination, but not control frames.

I think so but the exact definition probably depends on the actual
underlying physical device.

> Regarding tracing, sopme things I don't like so much about that
> approach:
> 
>   1. Harmonization.  Tracing paths, as general rule, are not
> "standardized" interfaces across multiple NetDevice types.  If I want
> to capture frames in both csma and wifi netdevices (which I really
> do), I'll have to code a series of IFs to check what is the type of
> the netdevice I want to monitor and what trace path and callback type
> I can use for each device type.  Extending the NetDevice class with a

You can also just use '*' in your trace paths:
/NodeList/*/DeviceList/*/$ns3::CsmaNetDevice/...
/NodeList/*/DeviceList/*/$ns3::WifiNetDevice/...

which will connect only to the matching devices.

>  new SetPromiscuousReceiveCallback API, on the other hand, pushes the
> harmonization job onto the netdevices themselves, where it belongs;
>
>  2.  API inconsistency.  Using netdevice tracing directly does not
> integrate as nicely with the Node::AddProtocolHandler API style.  In
> addition, why do we have NetDevice::SetReceiveCallback?  You could
> have said the exact same thing, to use tracing instead of providing an
> explicit callback API.

If the "promiscuous mode" is really used for tracing only, then,
clearly, using trace hooks is the right way to go. 

However, the use-case you have described in your first email, describes
using "promiscuous" mode to implement a layer 2 learning bridge, which,
indeed, does not sound like the best use-case for tracing. Is this
really what you are trying to do ? Or did you simplify your use-case for
your email ?

Mathieu