nth routing - VPN for bandwidth aggregation to data centre

RouterOS General
1

We have 4 adsl lines which we currently balance using a non mikrotik solution, and have a data centre close by, since we have control over either end of the connections i would like to “Bond” the ADSL lines to the data centre and aggregate the bandwidth of all the lines and make use of the high speed link in the data centre for internet access. The reason i would like to “Bond” instead of “Balance” is i need more speed per tcp connection.

One suggestion i’ve had is to establish multiple l2tp tunnels to a Router-board in the data centre and then use nth routing to distribute the packets over all the lines essentially increasing the speed of a single tcp connection. Something like diagram below, the problem i have is i can’t find much info on this kind of configuration, has anyone got any example configs, suggestions or alternate ideas to aggregate bandwidth across multiple adsl lines to a data centre?

                      l2TP Tunnel
        ADSL1 <-------------->  L2TP IP1
RB <->  ADSL2 <-------------->  L2TP IP2  <-> RB Data Centre <-> Internet
        ADSL3 <-------------->  L2TP IP3
        ADSL4 <-------------->  L2TP IP4
2

I run something quite similar, just 3 links and PPTP.

  • You need 1 IP address per link on the data center.
  • You force route that IP address per link over a different ADSL connection.
  • YOu then use nth rules for all traffic to distribute the traffic over the links.

It is QUITE simple to set up.

SADLY:

  • One link fails - you are down. Fixing that is complex (scriptrs for events), I never bothered.

It would be a LOT easier to get a MLPPP capable router (in the data cneter) and use PPTP with MLPPP, as it handles link distribution etc. automatically. SADLY Mikrotik does not care about this scenario and thus does not bother a MLPPP Server into RouterOS.

3

Thanks for the reply,

Couple of questions:

The tunnels that you establish to the Data Centre Routerboard, Are you routing a “public ip” to the tunnel clients or do you nat in the data centre?

Also the nth rules are quite new for me, im guessing that nth rules have to be applied at both the data centre and the site with the adsl lines?

An chance of an excerpt of some nth rules, so i can get a better picture?


Thanks