I want to give the whole bandwith to a PC when the other is not connected, and a 60%, when both PCs are connected.
The other Pc should be limited at 40% of the bandwith.
The bandwidth is known, and pretty stable.

Is it possible to do this with RB450G?

I think you are looking for the PCQ,
http://wiki.mikrotik.com/wiki/Manual:Queues_-_PCQ
which able to divide bandwidth equally between the clients.

Hi,

Thank you for your reply.
I realized that I forgot to mention some aspects. The external bandwith is most of the time stable, so I know the exact values, but the metropolitan bandwidth varies, from 10 to 100mbps.
I'm a bit confused on how to implement QoS, because I want to allocate the bandwith as efficiently as possible.

PCQ allows you to distribute specific amount of bandwidth or even when total bandwidth rate is unknown.

You can also do some bursting with Mikrotik. Not exactly your answer, but might be able to be worked into a set of rules.

PCQ seems to work pretty nice. And it was very simple to set.

Yes, I think some burts would be even better, but my experience with RouterOS/networking is very poor.
Where should I read about bursting?

Btw, I face new challenges every week:
http://forum.mikrotik.com/viewtopic.php ... 49&start=0

Just use PCQ, dont complicate with bursting, NOT YET... Until you get experience, setup according the examples in the wiki it's very easy and works PERFECT

Back again with this topic.

Things still don't work as expected.

So, for the moment I have 2 PCs behind a Mikrotik router.
The problem is that the one connected to ether2 eats as much bandwith as possible, leaving almost nothing for the one connected on ether3, so that surfing is very very slow.

What are my options to solve this problem?
(Prioritize traffic, dynamic bandwith allocation, others?)

To make things worse:
-one of the PCs is left for download(dc++/emule/torrents) 24/7.
-I have different bandwith limitations from the ISP: external 2mbps down.1 mbps up and metropolitan which varies a lot, and goes up to 100mbps.
-the PCs are behind the router but in 2 different networks(i don't think that this is such a big problem, but I've mentioned it anyway)

The idea is that I cannot limit the 24/7 PC to a fixed bandwidth because I'd sacrifice the metropolitan speeds. I think you get my point, right?

So, what can I do to make surfing, on the PC connected to ether3, snappier and a bit faster?

this means your PCQ configuration is incomplete or incorrect. Post everything you configured for PCQ to work

Yes, I realize now that it was incorect(but I still don't know how to do it right 100%). All I have done was to assign a PCQ queue to all the used interfaces.
No classifier...

ether1 is WAN, ether2 and ether3 are LAN, each with it's own separate network. And I'm using NAT between them.

Selecting Dst. Address Classifier would be enough? Or I need to implement PCQ in "Queue Tree"?