How to send a Notification to the previous Router?

[Nuno Eliseu]

Hello,

I'm implementing a Queue controller, just like "red-queue.cc" but more complex, and I need to send notifications when the previous router is causing a congestion. Is there any code, inside ns-3, that I could have a look at, to see how it is done or isn't it possible to do it? 

I'm just programming the queue. My code extends the "queue.cc" file and if there is any queue type that sends a notification back when ever there's a congestion, that would be great.

Thank very much for your time.

[Tommaso Pecorella]

Hi,

the real question isn't how you can do it in ns-3. The question is if you could do it in a real system (and then do the same).

Two routers are usually linked through a communication channel. In Internet the channel is used for both the data and the signalling.

So, the question is: do you want to send a notification to what node ? How ? (TCP, UDP, ICMP, etc.). In-band or out-of-band ?

Don't try to use shortcuts, you'd only get a mess.

Cheers,

T.

[Nuno Eliseu]

Hello, 

I'm working with Ethernet packets, and I'm implementing a new queue for the Routers and the congestion control protocol. What I want is, for example, if you have two routers connected to an other router, I want to send a little packet, if one of the routers is causing troubles, to reduce the bandwidth. I want to do that inside the queue or the point-to-point-device. I thought about ICMP, but I don't really know if that can be implemented inside my queue or the p2p-device.

Thank you,

N.

[Tommaso Pecorella]

Hi,

technically you could send an ICMP from inside a NetDevice.

Practically it's a bad idea (you'll end up in a nightmare of dependencies).

You should use a "management" module (an application) monitoring your netDevice and sending messages if needed. That will be easier.

T.