There are Mikrotiks. How to solve the problem of communication quality in a large cluttered local network, without losing speed?

Question

Mikrotik

There is a local area network branched out across the city, organized through a provider.
Formally, the speed is more than sufficient.
Formally, there can be no left traffic, because the provider provided Vlan.
In fact, the stability is not very good.
The provider swears and swears that everything is perfect with him.
Some time ago there was a problem, from one of the long-long disconnected cables in the building we left long ago, some kind of garbage came in, which made the work on the local network terribly slow. The cable was found and cut. That problem was solved.
Now the situation is similar. It is not possible to repeat the solution with cutting unnecessary cables. Since there is no access to unnecessary cables. And the provider takes money only for those ends that we really exploit.
There are Mikrotik 2011, you can buy more, only simpler models.
And put in all offices.
Next, organize your own private network over the provider's Vlan.
There is no special need to make protection with encryption.
I just want to ensure the stability of this virtual network, cutting off junk packages.
Network mapping programs behave strangely. Some of them do not see any devices that are not ours.
Someone sees some "left" devices that cannot be. But when we try to access these devices (by ping, telnet, etc.), we don't see them.
We assume that this is littering someone outside of our network. Of course, it is possible that this is something from our equipment, but it is not so much - less than 10 of our devices (computers and network printers) throughout the network.
What would you suggest to isolate junk traffic?
Which Mikrotik model is easier to choose for some offices, except for the already existing 2011 models. There is no need for Wi-Fi.

Answer 1

Water is dead * I ....
Performance test results on each page there is equipment (I'm talking about the Mikrotik site) .... see what fits.
They wrote x * yni, you yourself understand that you simply did not indicate the "thickness" of the channels ....

Answer 2

I came across garbage from providers, I decided radically - I refused to use them)))
Tiki perfectly hold tunnels in large quantities, I would look in this direction.

Answer 3

+1 to Maksim
Who litters? Trash what? On what ports/vlan? Nothing is clear, and therefore it is pointless to advise anything. You need to see the config + detailed network diagram + problem traffic logs. No other way.
Advise equipment without even knowing approximate requirements? Take ANY model, you will not lose!
Well, since there was only one formulated question, "What would you suggest for isolating junk traffic?" I will answer: use firewall.

Answer 4

“The provider swears and swears that everything is perfect” and
“Someone sees some “left” devices that cannot be. But when we try to access these devices (by ping, telnet, etc.), we don’t see them ."
does not fit.
Either the provider does not isolate you normally, or it isolates you, and there is a crooked configuration on your side.
All microtics that run on ROS and with advanced-tools installed can help with garbage analysis.
Determine what kind of garbage and where it comes from, then it will become clearer.
But this will not help if the problem is still with the provider.
Then there is only one option - to change it.
In my city, Rostelecom also behaved - "everything is in order with us, most likely you have something."
Changed provider - all problems are gone.