PCQ

RouterOS General
1

Finally got a pcq rulle working properly. I have two problems:

  1. System resources show 100% cpu usage whenever pcq is running. M router is an Athalon 1.8 GHz with 768 MB RAM, and I have about 200 clients. Everything seems to be running fine though, with no noticeable lag when I log-in with Winbox.

  2. Of course pcq means “per connection”, and I notice that a client performing multiple downloads simultaneously gets the full rate for each download. Is there any way to limit them “per client” without making a separate rule for each client?

Thanks!

2

what classifiers did you use in /queue type? could you please put here the printout from that menu

3

Here they are. I’m not sure whether pcq-limit is set properly. Is this the number of simultaneous connections?

4 name=“PCQ-Download” kind=pcq bfifo-limit=15000 pfifo-limit=50
red-limit=60 red-min-threshold=10 red-max-threshold=50 red-burst=20
sfq-perturb=5 sfq-allot=1514 pcq-rate=4000000 pcq-limit=300
pcq-classifier=dst-address

5 name=“PCQ-Upload” kind=pcq bfifo-limit=15000 pfifo-limit=50
red-limit=60 red-min-threshold=10 red-max-threshold=50 red-burst=20
sfq-perturb=5 sfq-allot=1514 pcq-rate=5000000 pcq-limit=100
pcq-classifier=src-address

4

pcq-rate (integer; default: 0) - maximal data rate allowed for each PCQ sub-queue. Value 0 means that there is no limitation set

this property sets the maximum for each client in your case. how much network traffic do you have?

the number of simultaneous connections may be limited in firewall. please see the manual for the example.

5

Let me explain… if you set pcq-rate=128000 that each of you clients will download(upload) with 128kbit :slight_smile:

6

So then is it that pcq-limit is for the entire queue and pcq-rate is per client (actually per connection?)

Any idea why I get 100% cpu usage as soon as I turn pcq on? It is 1.4 GHz with 768MB of RAM, so should be powerful enough, don’t you think?

7

quote again from the manual:

pcq-limit (integer; default: 50) - how many packets to hold in a PCQ

that does not mean speed - that means amount. in pther words, when the queue is already full (i.e., the speed has reached the maximal value, and PCQ is not allowing any more packets to pass), how many packets to have waiting for their turn to be sent. i would suggest it to be as low as possible, as this, in my opinion, would reduce delays and cpu load. not sure about the later, though…

8

My apologies to the Mikrotik folks. Turns out it was not the PCQ that was causing the problem but our own stupidity. We had a memory chip mismatch (one 512 MB and a 256 MB DDR) in the computer. Changed them both to 512 MB DDR and now cpu loading is only 4-6%.

Regarding the pcq-limit, I find this a bit confusing as I wonder how you know when you have the setting correct?

9

Seems you have better luck locating these things in the manual than I do. Perhaps if the manual were better organized or had an index? In any event, would you mind advising which section of the manual you found this? It doesn’t appear to be in “Firewall” section. Thanks!

10

try queues, or bandwidth management…

There’s also this really neat feature “search/find” its built in to most text editors, document viewers, web browsers. :slight_smile:

Mikrotik goes into a lot of detail on their queues/bandwidth management, there’s also other free documentation on how bandwidth management and QoS work available on the web.

11

here is the link:
http://www.mikrotik.com/docs/ros/2.8/ip/firewall||0.48746797371059375

12

Well, with all due respect, this is about the extent of details on connection limiting that I found in the manual.

“connection-limit (integer; default: 0) - match the number of concurrent connections from each particular IP address”

I think I could have guessed that. I agree that not a lot of explanation is really needed, but perhaps a few lines, such as a notice that it only works with TCP, for example.

Is there a way to limit the number of udp connections too?