RT-AC68U Dual wan question

Wutikorn

Senior Member
I am looking at buying the RT-AC68U, largely because of the dual wan support.


I have 2 ISP providers, one fast, one a bit on the slow side.

I work from home, so I have the slow one largely for a backup. Either ISP would get the job done.

I just wanted to ask what is your experience with dual wan support for load balancing.

Thanks
Michael
I have no experience, but I saw that u can set it to do load balance and also set ratio of distribution(mainly is network speed ratio). However, in Asus router interface, it says that if the difference in network speed is more than 10Mbps, you will get better performance if you use failover mode.
 

RussellInCincinnati

Senior Member
I've found that the dual WAN on these routers doesn't work, I've tried the most up-to-date Merlin.
On the RT-AC68u version _59 (May 2016), failover, with failback, works perfectly, when the primary WAN connection is through the WAN Ethernet port, and the secondary failover Internet connection is to a LAN port such as Ethernet "port 1".

You can disconnect the primary WAN connection, watch its status become "disconnected", and wait 60 seconds...and watch in the router interface screen as the secondary WAN port status label goes from the words "disconnected" or "standby" to the word "connected".

After testing the failover Internet connection, then you can plug the primary WAN connection internet cable back in, wait 70 seconds or so, and watch on the router interface screen as the primary WAN status becomes "connected", and the secondary WAN port status becomes "standby".

It is now obsolete information to think that, as of Merlin _59 software on the RT-AC68u router, with Ethernet connections to 2 different Internet providers, that the failover or failback feature does not work. It definitely works.
 

Marvin A

Occasional Visitor
I have my AC68U set up with a 3G/4G backup connection. Just not sure on the settings... I think I know what "delay" and "interval" mean, but what do "Failover detect time" and "Failback detect time" mean?

I'd obviously like my router to switch to the backup connection ASAP when my main connection fails. As it is, it takes up to a minute before the backup 3G/4G connection is up and running.
 

Wutikorn

Senior Member
I have my AC68U set up with a 3G/4G backup connection. Just not sure on the settings... I think I know what "delay" and "interval" mean, but what do "Failover detect time" and "Failback detect time" mean?

I'd obviously like my router to switch to the backup connection ASAP when my main connection fails. As it is, it takes up to a minute before the backup 3G/4G connection is up and running.
If I remember this correctly, failover detect time is how many times the router ping google.com, for example, before the router moves to secondary WAN. If you set it to 10 times and 6 second interval, it will wait, while not having internet, for 1 minute(10x6sec=60sec)before it realize that it should move to secondary WAN. On the other hand, failback detect time, I am 70% sure, is how many time the router check the connection when it is using secondary WAN and detect that the main WAN is working again before it switches back to the main WAN.

I want my router to switch ASAP too, so what I set my router is having detect interval set to 1 second, and failover detect time set to 15 times, which should be enough, in my opinion. However, I am not sure if what I am doing is a good thing, so you might want to wait for a few more people to add information. If failover detect time value multiply by detect interval is less than 5 seconds, for example, there could be a lot of unnecessary switchings between main WAN and secondary WAN. For Failback detect time, if you want, you can increase the times it takes before switching the network back to make sure than the main WAN is more likely to be more stable.
 

primitivo

Senior Member
I have just tested both the failover with fallback and load balancing on MerlinWRT 380.61_alpha1 . Both features seems to be working well. No issues with switching over from WAN1 to WAN2 and vice versa once WAN1 is back online.

As for load balancing:

Considering that two WANs are pretty much the same speed wise, would it make sense to change the load balancing ratio from 3:1 to 1:1 ?

So if I have PPTP server running, does it mean I can access it from both WANs IP?

What happens in case of VPN clients? If there is one OpenVPN client running which WAN establishes the connection? Always primary? What does secondary WAN do in this case?
 

KoryHu

New Around Here
I have the same situation. (with AC55U but I think its the same)

From today I have Dual Wan setting, with load balancing, and I successfully set up VPN too. On the dual wan screen set the routing options (rules), destination and source IP. (source is the VPN client public IP, destination where is the VPN server running). You can change which WAN will carry the traffic.

It is working! (only one VPN tested, but I thing it is good.)
 

KoryHu

New Around Here
Correction after 6-7 hours: Load balancing doesn't work as I wanted with VPN. People (clients) get cut off when their packets start coming from another IP in the middle of a session, this makes OpenVPN server "TLS key negotiation failed" messages, and connection drops and sometime never connects again.

Any other types of usage, load balancing is basically working. I don't have an idea what means the default 3:1 ratio, I did not notice any change, changing this value.

I think basically load balancing in this Asus routers works like "round robin".

So I consider using only failover mode.
 

primitivo

Senior Member
Failover does not even work for me on dual WAN. Had to switch to Tomato by kille72 , now I have 3x WAN failover working like charm. Unfortunately Asus broke something with Dual WAN in the last months... or perhaps never got that thing right.
 

Deepcuts

Regular Contributor
Sorry for resurrecting this thread, but this one seems to discuss the problem the most.
Using Merlin's 384.6 on RT-AC68U and trying to deploy a backup/failover 4G router connected to LAN4.
The backup WAN is sitting in Cold Standby and never triggers when the primary WAN looses internet.
Both connections work in load balance.
Anyone using such a solution with this model and is able to get it working with fallback?
 

Wutikorn

Senior Member
Anyone using such a solution with this model and is able to get it working with fallback?
Never had it working with auto fallback in either AsusWRT Merlin or stock firmware for years having two PPPOE fiber connections. Not sure if Asus has done anything to fix it since RMerlin doesn't touch Dual WAN code.
 

primitivo

Senior Member
Never had it working with auto fallback in either AsusWRT Merlin or stock firmware for years having two PPPOE fiber connections. Not sure if Asus has done anything to fix it since RMerlin doesn't touch Dual WAN code.

I read somewhere that they promised to fix dual related WAN issues this fall. After switching to Synology RT2600AC I forgot what dual-wan problems are about, since everything works as it should. My RT-AC68U serves as AP now.
 

hotsauce2007

Regular Contributor
I am trying to figure out how to deal with all those problems, over here the ac86u keeps disconnection from ISP1 to ISP2, I´ve tried the failover option, load balance is not a option for me and I don't have any interest on that, my idea is just keep the internet running, right now this is my scenario, probably the firmware works better if you use a 4g MODEM in the usb port, I will test it later, probably plugging two routers ( wan and lan 1 ) can messy with the router system, I don't know, just guessing...



.
 

fbicknel

Occasional Visitor
...
The RT-AC68U IS NOT CAPABLE OF FAILOVER AT ALL !!!
It is not able to detect by itself a lost connection and commute on secondary.
I believe I can second this:

I just set up my phone as the secondary WAN (typing this using that connection, aamof). I thought that by manually switching off the primary WAN the secondary should jump in eventually and take over. Nope... it stayed cold-standby stubbornly until I bounced its (secondary WAN) connection. Then it changed to hot standby, but stubbornly refused to take over WAN duties at all.

I wound up having to pull the primary WAN Ethernet cable, and finally it decided to failover.

I have this router plugged into my provider's router (an Arris BGW210-700 in passthrough mode). I suppose my next test will be to see if pulling its plug will nudge the Asus to use the secondary. I don't hold much hope for that working, though.

Well, that's no fun!

I'm using AsusWRT Merlin version 384.6 on my RT-AC68U.

Oh... and the USB port doesn't seem to provide enough current to keep my phone charged, either. :(

update:
I tried making the phone the primary and moving the ethernet to secondary. Wow - the same thing happens. It even connected to the secondary first. This is frustrating.
 
Last edited:

ApexRon

Very Senior Member
A dual WAN function, whether used as load balancing or failover, is a challenge for any router, not just ASUS. I provided Level 2 and 3 support for Cisco, Bay Networks, and other routers back at Verizon and a network design with those requirements was always problematic. For failover the router design engineer had to correlate all the possible kinds of connection failures and attempt to write the firmware to account for all possibilities. It was Voodoo engineering and always had an Achilles heel. One of the problems with load balancing is that some connections (TCP/UDP) would never disconnect though they were no longer in use. Consequently, the balancing mechanism would incorrectly choose a path. Additionally, another layer of complexity were the various routing protocols that the ASUS doesn't support.

Bottom line, if dual WAN works for your environment, fantastic. Just be aware that situations will arise where it may not. Open cases with ASUS for issues you identify but know that their engineering will require detail from you so they can recreate in lab.
 

hotsauce2007

Regular Contributor
A dual WAN function, whether used as load balancing or failover, is a challenge for any router, not just ASUS. I provided Level 2 and 3 support for Cisco, Bay Networks, and other routers back at Verizon and a network design with those requirements was always problematic. For failover the router design engineer had to correlate all the possible kinds of connection failures and attempt to write the firmware to account for all possibilities. It was Voodoo engineering and always had an Achilles heel. One of the problems with load balancing is that some connections (TCP/UDP) would never disconnect though they were no longer in use. Consequently, the balancing mechanism would incorrectly choose a path. Additionally, another layer of complexity were the various routing protocols that the ASUS doesn't support.

Bottom line, if dual WAN works for your environment, fantastic. Just be aware that situations will arise where it may not. Open cases with ASUS for issues you identify but know that their engineering will require detail from you so they can recreate in lab.

Totally agree, I just want to use as a failover setup, sometimes the ISP drops to change the IP and I run out of internet for a couple of minutes, maybe 2, I wish I was able to have internet in this period since I have another link ( 25mb ) just as back up,
 

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