Data Centers

What to watch out for when adding a second router into a SOHO network

Scott Reeves runs through some guidelines for adding a second Wi-Fi router to a SOHO network.

Sometimes, you need to expand a Wi-Fi network, whether it is to accommodate more devices or you're adding an extra office. What follows is a quick guide on the items you need to plan in advance and a few things to look out for when another wireless router is added to your network. It is a general guide, as opposed to being tied to specific brands of Wi-Fi routers.

Connectivity

The first part is to decide how to connect the two routers together. The best solution is to have a cat 5e cable running from a port on one router to a port on the new router. This may mean a little bit of extra work. In our case, the cable had been run already and ports were installed at both ends of the office. The original intent was to use one end as the server/switch room and the other end as the print room. We simply re-used the printer outlet and plugged the new Wi-Fi router into the old printer outlet. Using cable is probably the best way to go; there are Wi-Fi routers that can be re-configured to act as range extenders, but this tends to suffer from the drawback that you lose a slice of the spectrum (and hence throughput) that could otherwise be used.

DHCP

If you use DHCP, then the next step is to decide where the DHCP server should reside: on the new router, on the existing router, or on a server. Alternatively you could switch DHCP off and assign every device an IP address. If you keep DHCP, then you may want to exclude some devices, such as (for example) the new router, any NAS that is on the network, and any servers that require fixed IP addresses. Whatever you decide, ensure that you have DHCP on one router only.

Subnet

You probably want to make sure your new router is on the same subnet as the existing router.  It is best to assign the IP address of the new router as a permanent one, in which case you should exclude it from the DHCP range. The assumption is that this is a SOHO network, which by definition will be a small network, in which case putting the router on the same subnet will be sufficient.

Alternatively, you could create another subnet. This would mean extra work in configuring routes, and may cause issues with printing to any printer that is on the other subnet. Unless you have some good reason to operate separate subnets, it is probably best not to do it on a SOHO network.

SSID

You also need to decide what SSID you want to use, or whether you want the same SSID. Sometimes having a different SSID can assist in isolating issues. You will know pretty quickly which router has a problem. There are no strict rules on whether you keep the same SSID for both routers or use different ones for each router.

A few words of caution: Selecting ports and channels

Some routers have a separate port that is labelled Internet. If you are adding a second router, then you do not use this port. You use one of the standard Ethernet ports instead.

Before starting out, make sure you know how many devices will be on the subnet. The best way to check this is to log in to the existing router and see what IP addresses are currently in use. You may be surprised that the network that you thought had just a couple of laptops and a server is actually home also to several tablets and a couple of smartphones. Check before you begin.

Make sure both routers auto select which channel to use. Usually, a wireless router will first scan the channels, looking for a vacant one to use. Depending on the algorithm, they will usually pick a channel that is separated in frequency to a neighbouring Wi-Fi router.

If you do manually set the channels, then beware of the following scenario. A neighbouring Wi-Fi is set up with a hidden SSID and also has a manually selected channel. Your Wi-Fi may now experience interference, particularly if the neighbouring Wi-Fi network is using your channel. In this case, the throughput will be reduced, and isolating why this is occurring could take some time. Setting the router to auto-select the channel mitigates this issue.

In summary, adding a Wi-Fi router to a SOHO network is not complicated. All it needs is some planning beforehand, and careful configuration of the wireless components.

About

Scott Reeves has worked for Hewlett Packard on HP-UX servers and SANs, and has worked in similar areas in the past at IBM. Currently he works as an independent IT consultant, specializing in Wi-Fi networks and SANs.

24 comments
stelellico
stelellico

As I have done here in my house, I have first a main Lynksys wireless router with IP 192.168.1. Then, to this router a second Netgear router is connected with a different Ip range: 192.168.4.1. In addition, in the second router you should disable the DHCP address release and enable the router as a bridge (if that feature exist in your router). Last but not least, the second router needs to be connected to the first router Via Lan and not via Wan.

zaphid
zaphid

Is that this article appears in the Data Centre Blog, and was promoted by email in that category... and talks about a home or SOHO issue

dave
dave

Channels interfere with each other. Channels must be 5 apart or they interfere and reduce thruput. ie. 1, 6 and 11 do not interfere. However channel 1 and trying to use 2, 3, 4, and 5 do. 5 and 9 also interfere. If you want to use 5 then 10 and 11 are your only options for the second AP. If you use 9 then only 4, 3, 2 and 1 are options. Get a WiFi tool like Xirrus. Scan for what is out there and then decide. If you are using Ch 1 and channel 6 has one AP but at -40 and 11 has many but at -80 then use 11 for your second AP. Many at very low power (further away from you) is a better than one at high power (closer to you). Less interference and better thruput for you. However in high WiFi density areas all bets are off.

weaved
weaved

If you want to extend the wireless network why not just get a wireless access point? Wire it to the router, give it an IP address on the network and set it to AP mode.

javierrosado
javierrosado

Why using a router when you are not using any routing for the new network. You are wasting the routing capabilities by not using the WAN port, DHCP server, and other features. According to your scenario, you are using the router in bridge mode, so why not using an AP instead. It is a lot simpler to use and configure and again, it is right device to use in such a scenario.

simonc
simonc

Most small office business users I know won't want to spend the cash on the more sophisticated type of equipment that muto@ is referring to but they will have an old SOHO router lying around that they can use to extend wireless coverage and add switch ports. Scott's advice if perfectly valid and well put but I'd just change the article title. All you're doing is turning the router into a second wireless access point Scott. The routing capabilities of the device are not being used at all. How about changing it to 'How to use that old SOHO router as a second network access point.'?

alexisgarcia72
alexisgarcia72

This article is not about having two routers on the network, you are just adding a 2nd Access Point to extend WIFI Coverage. Initially, I think this article was related about adding a 2nd router in order to provide load balancing, high availability to a SOHO network trough the use of 2 x ISPs. There is lot of new cheap devices to achieve that today. In regards to your article, you are right, if you add a 2nd AP's, you must disable DHCP in order to keep only one DHCP service running on the network. Using manual IP is not used anymore, all users with tablets and BYOD will have issues with manual IPs. You must keep a DHCP for sure, and if you have a server, the server normally must provide this service. You forgot about channel setup, perhaps is good idea to have primary AP in channel 9 and 2nd AP in channel 5 to avoid conflict and radio issues. Use WIFI extenders is a BAD idea. Instead, a professional must normally use cable installation for inter connections between 2nd AP and the network switch. I worked in enviroments where cable installation are not possible (historic buildings) so we use power line kits like SLING TURBO so you can use your power lines to distribute 100MB network liks around your soho for AP connections. Thanks!

muto
muto

Another useless article from the increasingly disappointing Tech Republic. To start off the title of this article if just plain wrong. "What to watch out for when adding a second router into a SOHO network" should be called "Adding Additional Wireless Access Points". And the information appears to be about 10 years out of date. Today their are excellent commercial grade Wireless Access points that offer easy to configure management tools that allow you to have the same SSID and provide seamless roaming for the client computer. Additionally they have POE for easy installation.

Adrian Watts
Adrian Watts

Just curious but why is the netgear router, which is on the same network as the linksys router being configured with an ip address in a different subnet. It would be easier to manage the netgear if it had an ip address in the same subnet as the linksys especially as any devices connecting through the netgear wlan are getting their dhcp from the linksys.. Just to clarify for other readers i do not believe you need to enable the netgear into bridge mode as you are not connecting it to the linksys via its wan port but by a lan port (it won't hurt but it is not necessary) disabling dhcp is all that is needed. Of course if it is a cable router you could connect it via the wan port in which case you would need to enable bridge mode.

muto
muto

I don't understand the comments about the high cost of a high quality WAP vs. the total garbage devices that are marketed to a home. The cost of these devices has dropped significantly in the last couple of years and I suspect that most people are making comments based on outdated information. Sure you could buy a junky n300 home router for $50 to use as a Wireless Access Point (WAP) instead of a quality Power Over Ethernet (POE) WAP for $200, but that ignores the cost of labor to install, configure, and support it down the road. Not having POE means having to compromise on the location for the installation which does not maximize the potential coverage of the device or it means paying the cost of a commercial POE WAP just to get an electrician to run a power outlet high on a wall to install a cheap home router. Also the commercial quality products like those made by Zyxel are rock solid reliable, have significantly better range/coverage, and the features that make it easy to add additional access points to seamlessly extend coverage if desired. And these commercial devices just plain work. I recall just 4 or 5 years ago that the commercial quality WAPs cost in the $500-800 range and if that were still the case that I would agree that a $50 home router may be more economical even when you add in labor, but at $200 these days it is far more intelligent to buy this sort of high quality product that will work reliably for years and in the long run be more economical than suffering with a series of miserable home routers that have zero support and are cheaper to just replace then waste your time calling the manufacture to discuss a warranty replacement...

Charles Bundy
Charles Bundy

Turning off DHCP in a home or small office environment is very reasonable as there are few devices. It's at least as reasonable as maintaining MAC tables for security. Trying to set channel spread is a bad idea on AP's. The channel noise may change based on what mobile wireless devices are wandering around. Let the AP/Client negotiate that dynamically and adapt to the environment. Using WDS and point-to-point isn't a [I]bad idea[/I] unless you are trying to pull double duty and have the WDS bridge serve as an AP. Your example of power line kits could be a [I]bad idea[/I] if the power provider or electrician puts your circuit on another leg of the transformer. :)

andronin
andronin

I came to read this assuming it was about routers and as Alexis commented this has nothing to di with routers but with access points :-| *sigh*

Charles Bundy
Charles Bundy

Having the same SSID for roaming is a feature of the client more than the AP. Any cheap Wi-Fi/Router will work. POE jumps the price point considerably (e.g. either POE switch or dongle pair) and the title does state SOHO. And what we would call [I]inexpensive SOHO Access Points[/I] have WAN ports labeled [I]Internet[/I], thus the term [I]second router[/I] is not misleading. That is what it says on the box when you go in Best Buy.

muto
muto

I disagree. The cost of installing a $50 junk router or wap is the same or more than installing a high quality $200 commercial grade one. And the $50 one will require maintenance in terms of rebooting or replacing and will have inferior coverage and inferior throughput. All of this makes what seems like an economical purchase actually cost more than making the wise purchase in the first place. If you are thinking what is he talking about, I can set these things up myself and so it doesn't cost anything, then think again. Your time is valuable even though you may not value it, it represents a cost and is not something that you can never reclaim. This sort of thinking is what keeps many small businesses small. Thinking just a little larger allow for greater efficiencies, savings, and the option to grow.

qwertyomen
qwertyomen

I can't see my self spending $200 on an access point when a perfectly good $20-80 crappy SOHO router will do the trick. Find one with a USB port and you can change the software on it to meet your needs. This article takes budget into consideration. Currently I have a load balancing router that provides DHCP, and two SOHO routers that I use as WAP's with their DHCP turned off. Unlike the article though, I have the wire from the router go to the WAN port on the SOHO boxes. The software takes care of the rest. Find some software for your computer (aircrack-ng?), or phone and figure out the channels that are used in the area. Manually set the router/WAP channels to prevent overlapping strong signals from neighbors, or your own WAP's.

Adrian Watts
Adrian Watts

as i would question the reasonableness of turning off dhcp, it just causes more problems except in very special situations, especially as most WAP allow themselves to be configured with the ip address of another dhcp server to use for handing out ip addresses when configured to use the same subnet. The rest i agree with.

Adrian Watts
Adrian Watts

no [SOHO] Wireless Access Points (WAP) have a WAN port, they just have a single RJ45 LAN port to connect them into the existing network, get it... Local Area Network. The WAP does not connect directly to the internet. The confusion stems from the typical combination of a router with a WAN and a WAP in one device, but they are different. The use of the term [i]second router[/i] [b]is[/b] misleading as virtually everyone here should know the difference between a router and a WAP and when hearing the term second router (rightly) assumes it is regarding load-balancing internet access rather than adding a second WAP. This is especially true as in the suggested setup the new WAP has the same subnet as the existing LAN which means that the WAP is not performing [b]any[/b] routing functions. If it was configured to use a different subnet it would be routing but it would still be a disingenuous description.

Charles Bundy
Charles Bundy

Can you back that up? What exactly does "junk" mean? I've had $600 dollar Cisco equipment lay down on me as well as the $50 dollar D-Link routers. For me the main difference between the two used to be number of processors and memory. I really didn't see much difference in QA wrt things like uptime or power. Matter of fact I've seen the D-Link outperform the Cisco in low latency traffic situations. Regardless this article is clearly aimed at folks with small footprints and practically non-existent budgets. Don't get me wrong I'm with you if you have the cash and need (e.g. hundred+ wireless devices). I've always subscribed to your thesis of "buy quality, cry once." But that is out of context for what Scott is covering.

Adrian Watts
Adrian Watts

In hindsight i should have chosen my words better and my use of the phrase "get it" was not what i intended to communicate, i was trying to be more tongue-in-cheek than it turned out. And you know what they say about assumptions [feeling sheepish]. The worst part is i have done what this article talks about. I have even taken a £40 netgear wg602 access point installed ddwrt on it and reversed its function and turned it into a bridge.

Charles Bundy
Charles Bundy

You were correct about my post being vague on WAP versus WiFi router thus the edit of that one sentence to clarify what was being talked about were cheap routers, not access points. Didn't change my overall argument one whit. I don't like being talked down to, and you started that. So yeah guilty as charged wrt slamming your post based on it's content, sorry about the carryover towards you. Doesn't change that your assumption on load balancing is incorrect tho.

Adrian Watts
Adrian Watts

then slam my post with a reply and a mark down. 1st paragraph wrt to Scott's article the general criticism is with the description of the post, or more accurately the lack of accurate description. Whilst it is clear after reading that Scott is talking about repurposing a cheap soho router as a WAP it is not clear from the title. 2nd paragraph, you seem to be the only person who isn't making the assumption that an article title mentioning a second router would be about load-balancing internet (and why bother mentioning second NICs) Still if you have to claim time as a measure of ability... i counter with ccna and ccnp so what do i know too?

Charles Bundy
Charles Bundy

SOHO equipment combines a router and access point in a sub $100 package. Cheap router with WiFi capability. The branding of these SOHO devices is [I]Router[/I] not [I]Access Point[/I] thus not misleading wrt Scott's article. Why would you assume second router = load balancing? Second [b]NIC[/b] but not second [I]router[/I]. Of course I've only been doing networking with various hardware and protocols for +25 years. What do I know? :)

chaltec
chaltec

@Adrian Watts my problem remains unanswered  i cant acess the router page of of my 2rd router to see it i have to go to TCP/IPV4 and disable it so dat i can manually enter the ip address subnet mask en gateway and after that only that router page works(192.168.0.1) of 2rd router all other pages cant be opened.

so in that case i cant access the router page of my primary router or router 1 as well wat should i do thanx

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