Good evening, team,
I have different providers on my main Mikrotik router.
E1, ISP 1, has 20Mbps, and E2, ISP 2, has 30Mbps. So, I'd like to know if it's possible to combine the two bandwidths to achieve a total of 50Mbps on my LAN?
Hi,
The answer is yes but .... there is no chance to have the single 50Mb connection from internal device to the Internet as the other side would not accept one connection coming from different IPs. You can have total 50Mb for different streams eg. any connection speed test opening streams to differrent test servers would report combined speed as these streams would be spreaded over two WANs saturating them.
Hello bartoszP
thank you for your answer
How can I get a total speed of 50Mbps?
Since it's not possible to get the total with different providers, what do I need to combine the two speeds to get a better connection for my LAN?
You need implement load balancing to get effecitve 50Mb saturating both links.
Lets ensure you understand the boundaries here.
The fastest connection you could possibly have is 30 Mbps.
The advantages of dual wan is MAINLY redundancy, in that if one internet provider is not available you still have internet. Now, if the ISPs are both from the same company/source, there is no redundancy and if the source is not available it doesnt matter if you have two of them. So ensure that if redundancy is your goal that they are two different providers ( cable/dsl for example ).
The other benefit is making more bandwidth available to the users so reducing slowdowns and bottlenecks as the user SHARE 50Mbps in total.
As Bartos pointed to a source of info no need to expand further suffice to say ECMP is the easiest method and simply consists of having two manual routes to each gateway of equal distance. DONE!
Getting straight to the point:
Either you have an agreement with your ISP that's the same for both lines,
or you rent a cloud service that aggregates the bandwidths via two VPNs or similar,
or no matter how hard you try, you'll get a maximum of 30Mb of speed on a single device.
The combined bandwidth used across all devices can reach 50Mb.
The alternative is to use programs that download a file from multiple sources, but you still have to make sure the sources are located a bit here and a bit there...
To sum up, 30 apples + 20 pears = 30 apples + 20 pears.
Until they are eaten or rotten. 
As I said,
I have Eth1 (ISP 1) and Eth2 (ISP 2)
with my LAN 192.168.XX.XX/24
Eth1 (20MB) and Eth2 (30MB)
Sometimes my connection becomes slow due to the huge network usage for the various download traffic.
That's why I want to be able to add the ETh2 (30MB) bandwidth to the Eth1 (20MB) if possible. At least I have a total of 50MB for the LAN, and at least I'm safe, with this bandwidth I can have a good connection.
That is the very purpose of dual wan or multi-wan "LOAD BALANCING", besides of course redundancy if one has two different providers.
The easiest way to get load balancing on the router is by use of the already available ECMP routing.
a. ensure you dont use ISP default route options ( ip dhcp client or pppoe settings ).
b. then create two routes to via ISP gateway IPs with SAME DIstance.
add dst-address=0.0.0.0/0 gateway=gateway1-ISP-IP table=main distance=1
add dst-address=0.0.0.0/0 gateway=gateway1-ISP-IP table=main distance=1
Done! The router will attempt to send traffic 50 50 to both wan connections.
This would be the mikrotik and many youtubers BullCrap approach by copping out and assuming private fixed WANIP information, instead of the more realistic and challenging dynamic WANIP information.
In the case of dynamic wanips, it will take a bit of scripting in the ip client settings etc.
THe problem is not the IP address you get, which the router normally learns and uses, but its the ISP gateway IP for the new connection. If that changes then you have to manually change it on the router and that is where scripts come in.