See if you can still get their x.25 service and bond two DLCI using robbed bit....
/S
No! You gotta keep ‘em separated!

Set the first router IP to 192.168.3.1 and the second router to 192.168.1.1...then piggy back them...worked for me on a Cisco e4200 and a Netgear router. Now I have 4 different wireless networks.
Might have interference on your WiFi, are you getting a good signal? Are you in a rural area, like no neighbors close by or suburban/urban? Just curious because adding another router/wifi to an existing router is just going to “slow things down a little more”
You might try black duct tape. I tried the regular grey stuff and it didn’t work.
might want to check this out.
http://www.speedguide.net/faq/what-is-the-best-wireless-channel-to-use-346
not much...good luck
Just went through something like this with my internet service. Turns out the line leading to my house was damaged and would only work intermittently. They ran a new line and now I’m back on the Information Superhighway!
I used to have daily (or multiple times daily) internet issues that required me to restart my WiFi rounter, cable modem, or both. One of the things that I think was contributing to (or causing) the issues was the growing number of WiFi devices around the house - Kindle, iPads, iPhones, laptop, Win10 tablet, SmartTV, DirecTV receiver, Roku box, etc.
My guess was that, to conserve power, these devices would either sleep, or shut down their WiFi adapters. Then, when waking or trying to hit the internet again, they would assume their last IP address was still theirs to use. Instead, another device looking for a connection might have been assigned that address by the router, and caused a conflict.
So I decided to implement “address reservation” through my router. I identified each devices WiFi adapter MAC address, and assigned an IP address to it. That way, every time it calls for the internet, it’s always getting the same address, and always assured that no other device has assumed it.
That eliminated about 90% of the issues, but I still have to do an occasional reboot. These seem to happen after one of my kids is at the house with one of their Macbooks. Might be totally unrelated to the Macbook - could be a site they visit (Facebook, and who knows what else).
To answer your question about linking the 2 routers, if you don’t need 2 WiFi signals, then just disable WiFi on one of them (leaving it as a router and DHCP server only). For the other, turn off DHCP and let it get an address from the first router. Any device that connects to that WiFi access point can get a network IP from the the first router.
You could try different channels, but you probably already have.
Can you disable the modem functionality of the N600 Netgear?

My router did the same thing in the months before it died. They have a life span of about 4 years.
I have an AT&T Uverse router that provides the WAN interface. I have a Linksys WRT54G router that connects to the Uverse router using a CAT 5 cable. I run the Linksys router in DHCP mode. I also have a Linksys N900 router that I imaged using dd-wrt so I could bridge it to the Uverse router. I have a computer connected to this router upstairs and the bridged dd-wrt Linksys N900 wirelessly connects to the Uverse router.
Everything works great except the bandwidth I get on the computer connected to the N900 dd-wrt router is about 20% of the bandwidth available to the other computers that are connected on the WLAN. I can live with it because it’s nominally 5Mb, and it’s just a homework machine that runs some paypal automation that I wrote, so it doesn’t need to be blazing fast.
The dd-wrt configuration is a bit tricky but if you take your time and read the instructions then it can be done. I was unable to bridge networks using the default Linksys configurations, and was only successful when I imaged the N900 with dd-wrt.
Are you logged in?
But, seriously, what you would normally do is put the N600 in AP mode, and disable DHCP on one of the routers. However, it doesn’t look like the N600 can be put into a true AP mode.
This guy says you can sorta kinda do it, though:
http://damien.co/general/using-netgear-n600-dgnd3700v1-extend-home-network-8747
Simple. Hire some tech puke to fix it.
Yu might be confused friend, this aint a techy blog.
Are you insane??? You want a bunch of baby router/modems running around the house? Ever try to potty train them? They chew up everything around them. They’re very territorial. And just try getting a good nights sleep with them in bed with their off-key snoring. No thank you. There’s a reason people keep them separate.
First are you talking about having two wan.connection. to the internet?
That different then having two router
Ditch using the old n600 modem router... you could use it but I've had that particular one and I've had bad experience with it being flaky
so do one of two things. have to isp send you a new modem router combo they say will work with your setup
or better... have the isp send you a new stand-alone modem then buy your own high quality wifi router to connect to it
adsl modem router combo can be very problematic in troubleshooting as its combining two devices that really function better as separate items
if you want to go with the modem router combo have the ISP send you one and then put all the responsibility isp for its functionality
what I don't understand is if the isp is pointing fingers your current Wi-Fi router ..and are they providing it.. that mean if they think that's the problem... they need to send you a replacement that’ll will work for you
One of the descriptions:
http://www.dslreports.com/forum/r28137734-Bridging-7550
Try to search with the following entry: "bridging Netgear 7550" without the quotations.