You are decluttering the electronics bin and remember that old router that you forgot to recycle. You begin to wonder…
Electronics resale value falls notoriously fast and it often makes more sense to repurpose or recycle equipment versus selling.
Does this old router have any use? Is there any reason to have two routers on the same home network?
In this article, we detail the reasons two routers may improve your home network and provide some tips on making sure your two routers play nice.
What do routers do? 
Obviously, your router “routes” internet traffic. What else?
Routers request and receive content from the Internet
When you use your internet browser to Google questions that led you to this article, your router sent a request out and received an answer back from the Internet, which the router then forwarded to your specific device (laptop, tablet, phone, etc).
This is the core functionality of any router and the reason for its’ name, however routers generally serve many other needs within a network that are less known and happen behind the scenes.
Routers can listen for requests and provide configuration information for your network
A router usually acts as a DHCP server. Since other devices on your network such as laptops, printers, tablets, Smart TV’s, etc don’t generally have a network configuration when they first boot up, they rely on the DHCP server for their configuration (IP address, Gateway, DNS, etc).
Routers can function as wireless access points
With the right security settings in place, your router can safely function as a wireless access point. Relating to security, the real muscle of a firewall in today’s world is no longer handled by your operating system but by your router. (But go ahead and keep updating your operating system!)
Routers can extend your network’s physical size
For wired devices, your routers can also “switch” it up and act as a four-port switch, thus extending the number of devices that can be physically plugged into your network.
Why might one network need two routers?
In short, to improve network range (to include the man cave), bolster coverage (to fix those dead zones upstairs), ensure reliability (you never know when the router is going belly up), and increase size (more ports in the storm).
How can you ensure your two routers will improve your network?
Multiple routers can make a network “two” crowded. Basically, you still need to think of one router as the “one in charge” and any functionality that leads to and from the outside world must go through just that router.
Choosing one of the routers to be the liaison to the outside world provides a starting point for the ways your routers should be configured the same and how they need to be different.
What functionality do you want to make sure not to duplicate?
You need to look out for WAN (wide area network) versus LAN (local area network) port connections (how the routers access the outside world), DHCP configuration (making sure both routers aren’t handing out conflicting information to devices on your network), and the routers’ channels (ensuring your routers do not talk over one another on your own network).
Most importantly, do not connect the second router via the WAN port
The WAN port (sometimes called the “Internet” port) is reserved to access the outside world. If you connect your second router on the WAN port, duplicate routing occurs because your network is now divided by a firewall and each device that connects to your new network is NAT’d twice (once by each router).
Instead, you should connect the routers together via any of the LAN ports (numbering does not matter). Remember, only one of your routers accesses the outside world. Refer to the diagram above.
DHCP configuration
Your home network is a bit like The Highlander – there can be only one! With two routers, you want to disable DHCP server abilities on the second router to avoid IP address conflicts.
Otherwise, devices on your network may acquire their IP address from the router that does not have access to the outside world or the device may not be known by the primary router. This would lead to that device being disconnected from the Internet.
Make sure your routers do not use the same channel
This is especially important if your two routers are in close proximity (within fifty feet or so). Channel duplication will cause interference and degrade the Wi-Fi performance of devices.
If your routers use 2.4 GHz, use a non-overlapping channel – see this article for help with choosing the best Wi-Fi channel.
Remember that frequencies matter
Consider whether the routers use 5 GHz versus 2.4 GHz wireless frequencies. This impacts the range and bandwidth of routers. A 5GHz router will provide faster data rates at a shorter distance while 2.4 GHz routers may improve coverage for farther distances at slower speeds
How should your routers be configured the same?
Under most circumstances, you will want your routers to have the same SSID (bonus points if it makes your neighbors laugh), the same security and encryption (WPA2) protocols, and the same key/password.
These configurations will ensure that your Wi-Fi devices can automatically connect to your network and will roam to your second router when you go out of the range of your primary Wi-Fi network.
Should you ever have different SSIDs on the same network?
You can use different SSIDs and keys/passwords for each router if you like. This creates a second wireless network with a different name.
This configuration does not enhance security, unless your router allows you to map each SSID to a different network connection using VLAN tagging. When a device connects to an SSID, traffic is passed to the associated VLAN which has its own security settings.
This is an advanced topic, but can be simple to set up if your router supports “guest network” functionality. Using this feature, guest traffic can be isolated from the rest of the network or limited in the services (and speeds) it has access to.
Wrapping up
In conclusion, there are several reasons having two routers on your home network may be an improvement.
Remember one router is in charge and does all the talking to the outside world, but as far as your network’s name, the routers should usually be in agreement. Plus, you can tell all your friends that you have a new tech upcycling hobby!
Andrew Namder is an experienced Network Engineer with 20+ years of experience in IT. He loves technology in general, but is truly passionate about computer networking and sharing his knowledge with others. He is a Cisco Certified Network Professional (CCNP) and is working towards achieving the coveted CCIE certification. He can be reached at andrew@infravio.com.