Enabling "Application Optimized Routing" breaks WAN Link Backup function

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Enabling "Application Optimized Routing" breaks WAN Link Backup function

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Enabling "Application Optimized Routing" breaks WAN Link Backup function
Enabling "Application Optimized Routing" breaks WAN Link Backup function
2023-01-13 09:07:15 - last edited 2023-01-13 10:12:19
Model: ER605 (TL-R605)  
Hardware Version: V2
Firmware Version: 2.0.1 Build 20220223 Rel.68551

Hello TP-Link

 

I migrated from ER605 v.1 to ER605 v.2 and tried to configure Link Backup between WAN and USB Modem (both these connections work fine individually).

 

I configured it as following:

 

  WAN Ports:  USB Modem and WAN

  Online Detection Interval : 1 minute
  Load Balancing Weight : 1 : 20   ( my modem gets 50Mbit/s max and WAN is 1Gbps )
  Link Backup: Enable
  Primary WAN: WAN
  Backup WAN: USB Modem
  Backup Mode: Always Link Primary
  Mode: Enable backup link when all primary WAN fails
 
What I found is that it only works when I unchecked (disabled) Application Optimized Routing:
 
As soon as Application Optimized Routing box is checked then the whole WAN redundancy gets broken - no failover to USB Modem and no return to Primary WAN when it comes back online !
 
When I uncheck Application Optimized Routing then WAN failover and fallback works OK (within the 1 minute detection interval).
 
This is maybe possible that for my scenario I just uncheck Application Optimized Routing because I have always only one WAN connection active, but this will be problematic for anyone using three WAN links with Link Backup, since then Application Optimized Routing would be helpful between the two WAN links that are both active. But also even in my scenario enabling Application Optimized Routing should not break Link Backup feature.
 
It seems to me that Application Optimized Routing mappings ignore WAN failover - but it should remap all flows when WAN failover happens. So the algorithm should be: first determine which links are online and then map traffic flows using Application Optimized Routing - but every time WAN link goes up or down the whole remapping should be re-done again by the Application Optimized Routing feature. Something is not working with how it is done in current firmware.
 
Please fix this as many users still report that TP-Link WAN redundancy is broken and does not work - and this is most likely because these people enable Application Optimized Routing and then Link Failover stops working completely.
 
Best regards.
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#1
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Re:Enabling "Application Optimized Routing" breaks WAN Link Backup function
2023-01-14 14:58:32

  @Smok I cannot get mine to work no matter what.
I installed it before I had my 5G modem router preparing for the 5g router as a backup WAN. The second I connected the LAN cable from that router, the entire internet went down.
I then activated the sim etc - and now the internet returned - but preferred to route traffic to the slower 5g (like 250/25 where my cabled wan is 1000/100 (measured 850/125)).

I have tried:
- interchanging the WAN - WAN2 cables (wan2 = LAN/wan port 1). That made traffic go to the other port but thru the same router
- enabling load balancing using measured bandwidth - that makes traffic distribute like 50%-50% (expected like 75%-25%)
- having online detection to auto (initial choice)
- trying a recurring tip here to set online detection to manual on both wan-ports and ping 8.8.8.8 (dns 0.0.0.0)
- this tip disabling application optimization - or enabling it
- having enable load balancing checked and unchecked

The only way I have successfully managed to make all traffic go to the primary wan-port is to disable the secondary wan.

At best I can bring the traffic to the backup WAN down to like 50% (when enabled)
My primary wan is faster and flat rate, the secondary is on a plan (and only 1/3 of the speed).

I have seen the router table has both routers LAN-IP set to 0.0.0.0 could it be that the traffic is always routed thru the first hit in the routing table?

ID Destination IP Subnet Mask Next Hop Interface Metric
1 0.0.0.0 0.0.0.0 192.168.52.1 WAN/LAN1 0
2 0.0.0.0 0.0.0.0 192.168.51.1 WAN 0
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#2
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Re:Enabling "Application Optimized Routing" breaks WAN Link Backup function
2023-01-14 15:10:53
OK but I posted this info about a specific scenario which seems like a bug, while you are replying but referencing a possibly similar but still distinct problem. Why not post it in a separate thread and ask for help with your issue ? I am asking TP-Link to fix this problem I was able to see and replicate at will - and I do not ask for assistance to get a basic scenario working.
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Re:Enabling "Application Optimized Routing" breaks WAN Link Backup function
2023-01-14 15:13:44

  @Smok OK, I will do that. Just thought You could tell me what setup workes for you.
Your tip apparently did not help make my attemps working.

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Re:Enabling "Application Optimized Routing" breaks WAN Link Backup function
2023-01-16 12:17:32

  @Smok 

 

The Load Balancing feature will be not active when you enable link backup, because only one WAN online all the time.

Just striving to develop myself while helping others.
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Re:Enabling "Application Optimized Routing" breaks WAN Link Backup function
2023-01-16 14:02:19 - last edited 2023-01-16 14:40:05

  @Virgo   This is somewhat true for my scenario where I have only one active WAN with USB Modem acting as a backup - I am aware of that but that was not my point.

 

1. BUT even in this scenario clicking on "Application Optimized Routing" should not silently break WAN connectivity !  Either this choice should be inactive or there should be an (i) icon with explanation not to enable this feature in this scenario. when there is only one active WAN link and a second link is only a backup.

 

2. SECONDLY - what about a scenario with TWO primary/active WAN links and a third backup link ? In his case "Application Optimized Routing"  seems desired - but can it be enabled in such case or will the Link Backup feature be broken again ?

 

Do you agree with the above ?

 

My reason to post the original report was also that I found that there are many articles and discussions on the Internet about this "Link Backup" feature in Omada and most of these articles say that the "Link Backup" feature is broken, does not work, use policy based routing instead etc. Only some tutorials and videos mention that Link Backup actually does work (or can be made to work) but then again they do not mention that enabling "Application Optimized Routing" will break it completely. So there is some communication gap towards the user base for this feature. And I believe that the behavior which I identified is rather a bug not a configuration error - as explained in my two point above.

 

 

PS. Well, my setup works now so I do not care that much - but does TP-Link care about other customers who struggle to implement "Link Backup" and give up, saying it's broken ?

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