As far as I understand, WRED is dealing not with the bandwidth but with queue length. So for class B 50K is guarantee but it can use up to 200K without packet drops if no traffic from other classes uses the bandwidth. As soon as class B packets places to queue (which means that available bandwidth for the class is not enough) and queue size grows over limits (there is a formula which WRED uses) then WRED starts to do its job. So in your case the packets dropping point is flexible and lays somewhere between 50K and 200K depending of other traffic in PVC and queue length.
and this is example of WRED configured interface, it has two drop counters, and random drop is higher than tail drop, I think random drop occurs before tail drop at some point, but i am not quite clear.
Well, I don't think that the fact that class B starts dropping means that class A will automatically also start dropping. If class A lays over its bandwidth guarantee it starts place packets to queue and then when queue lenght comes to certain value it starts dropping. If class A traffic is below the bandwidth guarantee the packets can be sent without queuing so WRED will not be involved even if WRED discarded some packets from class B.
Tail drop occurs when queue lenghth is over the limit. You are absollutelly right - random drops occurs before tail drops, but it doesn't automatically mean that WRED prevents all tail drops. WRED can drop some packets but if packets are coming fast enough queue overflows and ALL packets drops (tail drop). When the queue lenght comes back below limit WRED take care of packet drops again.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.