Per-Packet Routing

RouterOS Forwarding Protocols
1

Evening All,

Does anyone know if you can do per-packet routing with the Mikrotik? The nearest I have found is ECMP but the docs state that “A new gateway is chosen for each new source/destination IP pair” so therefore its technically not per packet.

Thanks
Jamie

2

Nth and routing marks should be able to do so. There are wiki entries for both. Nth can mark every nth packet with a routing mark. Seems kind of expensive though. Why do you need this? Are you sure that bonding with a balanced mode would not work better?

3

Hi,

Thanks for the reply, I did manage to work it out shortly after I have posted it! It seems to do exactly what I want! My reasons are that we use an ISP that allows us to send packets up any number of ADSL routers from the same routed IP block, that way we don’t have to worry about returning traffic coming down the sam line etc.. as it doesn’t matter! Does that sort of make sense?

I am interested in your ‘expensive’ comment. Its my understanding that nth should be relatively low processing power?

Also any ideas on the best way to shape the traffic using nth? I have two lines that sync as 1800 and one that syncs at 800, so I would like to send less traffic down one line…

Thanks
Jamie
http://www.fusionmanageit.co.uk
Fusion IT Management Limited

4

Expensive in resources is always a relative term. If it works for you, it works for you.

To balance roughly between 1,800 and 800 have 3 rules with Nth decisions, and have two send to one circuit and one to the other. That way you get a 2:1 split. If you wanted to you could do 26 rule for 18:8 (=1800:800) split but that would probably be overkill.

5

Yep that makes perfect sense, thanks!! Hit yet another brick wall!! How can you use Nth for packets that are NAT’ed or orginate from the firewall ie IPSEC traffic and hosts that are hidden behind an IP address that is on the Microtik?

Thanks

6

That completely changes the scenario. You would be best off using PCC, which is a completely different load balancing technique and allows you to be stable on a connection basis (connections recognized as the same by the classifier always take the same circuit). Search the wiki for PCC and you’ll find a manual wi a detailed example.

7

Humm, interesting! I was hoping that Nth might do the trick as I actually don’t care about a connection taking the same circuit as our ISP doesn’t care either! Nth was working perfectly for all traffic that wasn’t IPSEC related and originating from the router! It seems to me it would be harder to shape traffic using PCC?

Thanks
Jamie

8

It is a little bit harder, but when a connection requires that something come from the same circuit/router/NAT IP then sticking the connection to a router via PCC is the best solution. You can limit the PCC to the connections that require stickiness and do Nth for everything else.

9

Can nth actually be used to match traffic that is sent from the router? I seem to be struggling!!

Thanks
Jamie

10

be aware that you will have packets arriving out of order if you just throw them out alternate ports. this will kill tcp performance and really hinder UDP stuff like voip. you should stick to connection based routing rather than per packet IMO.

11

If you have several ADSL lines, the best aproach should be MLPPP.

Best regards,

12

problem with mlppp is that requires your vendor to support that on their end. But that could solve a lot of issues. Also, as noted by posters before me - if you require connection “stickiness” and want to keep configuration relatively simple, stick with PPC if you have a lot of connections they will balance out beautifully.