Community discussions

MikroTik App
 
dejanjak
just joined
Topic Author
Posts: 2
Joined: Fri Jan 08, 2021 2:00 am
Location: Serbia

QOS - get management priority over rest of the traffic

Fri Jan 08, 2021 3:01 am

Hi all,
I've already tried to find the answer to my question [how to prioritise management traffic] throughout this forum with no luck.

What I have is a network of Mikrotiks, UBNTs, Cambiums, Netonixes, etc... mostly bridged. Customers connecting using PPPoE (with simple queues getting created on ppp connection established - using bandwidth limitations from radius server). It's (almost) impossible to use VLANs (and try to prioritise that way) so I'm trying to find out a way to do management traffic prioritisation over other traffic (including customers' traffic). This is to ensure availability of the network devices (ping, snmp, ...) in high loads.

Since there's no way of knowing exact bandwidth throughout the network (lot of WiFi links) I can't use QOS with configured limit-at or max or whichever parameters need speed settings - therefore most of the examples and studies (which involve "my ISP gives me xxMbps") are not useful :( ..

What I know and can use is the IP schema - all o the equipment use private IP blocks unique on the network.

Thanks,
DJ.
 
sindy
Forum Guru
Forum Guru
Posts: 6657
Joined: Mon Dec 04, 2017 9:19 pm

Re: QOS - get management priority over rest of the traffic

Fri Jan 08, 2021 8:12 pm

Well, you can use the IP schema to classify the traffic for prioritisation, but not to actually prioritize it at egress interfaces. And although you may store the result of the classification into the IP TOS header field and/or the 802.1Q tag priority field, the actual prioritization has to be done at every device on the whole path between the source and destination whose output path may have a lower bandwidth than the input one, not only on the Mikrotiks.

On Mikrotik, the queues are the only means to prioritize some traffic classes over other ones. You can queue bridged traffic if you activate use-ip-firewall under /interface bridge settings and if you disable "hardware accelerated bridging", i.e. forwarding by the switch chips. You need a parent queue with some unrealistically high max-limit, with two child queues, one for the management traffic and the other one for the rest of the traffic. Both will have the same unrealistically high max-limit, but the management one will have also the limit-at set to the same value, whereas the "rest of traffic" one will have a very low limit-at value. As a result, the queue holding the management traffic will always be served first. Packets from the other queue will only be delivered if the management one is empty.

RouterOS doesn't automatically respect TOS or CoS values, you have to use mangle rules to translate them to packet-mark values used as keys to select the queues. But these values may be respected by some other species in your network zoo, and assigning them at all sources may simplify the classification rules on mid-path devices. Of course you must downgrade the highest priority values in packets sent by customer equipment if you decide to respect the values network-wide.
Instead of writing novels, post /export hide-sensitive. Use find&replace in your favourite text editor to systematically replace all occurrences of each public IP address potentially identifying you by a distinctive pattern such as my.public.ip.1.
 
dejanjak
just joined
Topic Author
Posts: 2
Joined: Fri Jan 08, 2021 2:00 am
Location: Serbia

Re: QOS - get management priority over rest of the traffic

Sat Jan 09, 2021 8:57 pm

Thanks a lot,
Didn't think setting limit over the real network bandwidth/throughput might work.

Max-Limit + Limit-at for management only might do the tric!!! ;)

Cheers!

Who is online

Users browsing this forum: Bing [Bot], Mhrok, pvchip1, sindy, Zetle and 273 guests