What is WAN load balancing?
The professional routers that have two interfaces for the Internet WAN, we have the possibility of carrying out a load balancing of both connections. This means that the two connections will be transferring traffic, neither of them will be waiting. This means that, if we have two 300Mbps Internet connections, if we connect two or more computers, their traffic will be balanced between the two WANs and we will be able to achieve speeds of up to 600Mbps at most if the typical speed tests are carried out.
Depending on the load balancing algorithm and the options we have in the router, we can put some computers permanently on an Internet connection, and other computers on another connection. However, the most common is to use both indistinctly, doing a load balancing with a «Round-Robin» algorithm, however, we would also have the possibility of using a WAN as the main one, and in case we are using everything the bandwidth, which begins to move traffic to the other Internet WAN.
Configuration of the two WANs on the router
Configuring the load balancing in a professional router such as the D-Link DSR-1000AC is really simple, we simply access its configuration via the web, we will have to put the IP https://192.168.10.1 by default, and we will see the main menu from the router:
The first thing we have to do on the router is configure WAN 1 and WAN 2 to have an Internet connection. Depending on the operator that we have hired, the configuration is one or the other, in any case, the firmware of this professional router has all the typical configuration options to configure our operator without any problem and that it works correctly.
For example, we will have the following configuration options:
- Connection type: DHCP, static, PPPoE and also others like PPTP or L2TP.
- Enable VLAN Tag: we can put a VLAN ID in case our operator uses it
- Host name for the DHCP client if we use this
- DNS Servers: the DNS servers that the operator provides us or some customized ones that we put.
- MAC Address: this allows us to clone the MAC of the WAN and change it, in case our operator needs it
- MTU Size: we should not change it, the most common is to use 1,500 bytes for DHCP and static IP, and 1492 for PPPoE.
- Port Speed: link synchronization speed, we should always leave it in “Auto sense” so that it synchronizes automatically.
As you can see below, we have all the options to correctly configure the router:
Something very important to configure load balancing is to properly configure both WAN 1 and WAN 2. In the case of WAN 2, we have the possibility of configuring it as WAN2 or as DMZ, in our case, we have to configure it as WAN 2 from the Internet and put all the data of our secondary operator:
We must remember that this D-Link DSR-1000AC router allows a third Internet WAN through mobile Internet, if we put a SIM in a 3G / 4G modem compatible with the router, we can have an Internet connection through this line. In this menu we must indicate all the data of our mobile operator, such as the APN, username and password and more.
Once we have correctly configured the two WANs via FTTH or cable, and the third WAN (optional) via mobile Internet, we are going to see how to perform load balancing.
Dual WAN and load balancing on the router
In the section of “Network / Internet / WAN Mode»Is where we can configure everything to perform Dual WAN and load balancing. Mainly, we have two configuration modes:
- Auto Rollover– This mode allows you to use a WAN as the primary one, and in case it goes down, it uses the secondary WAN to send the traffic.
- Load Balance: there is a load balancing, some computers will go to the Internet through a link (WAN1 or 2) and the other computers through the secondary one, depending on the chosen algorithm (Round-robin or Spillover).
In the «Auto-Rollover» menu we can see how we should select the primary and secondary WAN, in addition to configuring the check that the WAN is up. In case it is verified that it is down, then the secondary WAN that we have configured will automatically come into operation, either WAN2 or WAN3 (mobile Internet).
Regarding how to verify that the main WAN works well, we can configure a ping to be sent to the DNS servers of the WAN, to other DNS servers that we want, and even to certain IP addresses. Logically, if we want this to be successful, we must put some IP or DNS addresses that are always working, such as those of Google, Cloudflare and others, and we must verify that there are no communication problems with these services.
If we select “DNS Servers”, we will put the IP address of the DNS server that we want.
If we select “Ping these IP addresses” it does the same, but in this case it will ping any IP address and it will not resolve domains.
If we click on «Load Balancing», we will have two types of load balancing:
- Round robin: In this type of load balancing, some computers will be on one Internet WAN and other computers on the other, equally. For example, let’s imagine that we have a total of 12 computers connected to the router and they want to go to the Internet, 6 of them will do it through an Internet WAN and the other 6 will do it through the other Internet WAN.
- Spillover: in this type of load balancing, we will have a main WAN where all the computers will be connected and will go out to the Internet, in case of a drop or that their bandwidth is full, then the computers will begin to go out to the Internet through the other of the links.
Of course, in this case we can also check the status of the WANs based on the DNS servers of the Internet WAN, a custom DNS, or ping an Internet IP address.
In the «Round-robin» mode we can load balance the three WANs that the router allows us, we will have to introduce a DNS server for each of the Internet WANs, we could put the same DNS server in all of them without problems . At the bottom we can see the time interval in seconds and the attempts until we verify that an Internet WAN has fallen.
We also have the possibility to configure the ping to different public IP addresses, both for WAN 1, WAN 2 and WAN 3 with mobile Internet.
If we select “Spillover mode” we will have the same configuration options, but at the bottom we will have additional options. We have said before, that Spillover allows to balance the traffic based on the bandwidth that we are using and also if one of the WANs fails.
- Load tolerance: if we exceed the threshold of 80% of the maximum capacity of the link, we will automatically begin to send the traffic through another WAN that is less collapsed.
- Max bandwitdh: here we have to put the real speed of our Internet connection, so that the previous value works properly.
We can put the value in bps, Kbps and also in Mbps. Nowadays, the most normal thing is to put 300Mbps or more, depending on our Internet connection that we have contracted.
As you have seen, configuring a double WAN with load balancing on this D-Link DSR-1000AC professional router is very simple, and will allow us to make a large number of configuration options to adapt it to our needs.