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network service detection & Protocol Binding

hi, i would like to better understand how "network service detection"  and “Protocol Binding” work. i have already read the documentation but it isn't very clear for me. In particular i would like understand

  1. how the two parameters: "retry count" and "retry timeout" are related each other, and
  2. the differences between the IP address types (“default gateway” , “ISP host” , “Remote host” and “DNS Lookup Host”) that we use to monitor if our WAN interface is healthy.
  3. and if those IP address types use the two precedent parameters in the same way.
  4. how Protocol Binding behaves on failed WAN interface when is is recovered  


In my opinion the rv042 works in this way, i.e.

  • It uses all the selected IP address types.
  • For each selected IP address type it makes a "ping test". If I specified the “DNS Lookup Host” it tries to resolve the name specified in the box with the DNS server I specified on setup->Network-> WAN Setting .
  • All  "ping test" will be made on the WAN interface that we I am configuring(I mean that it won't use the other working WAN interface).
  • If at least one of the "ping test" fails, the WAN interface is discarded(I mean that all “ping test” must work)

In particular for a selected “IP address type" on a working interface it works in this way: the RV042 makes a ping test i.e. sends 5 echo and waits the echo replies. If at least one echo reply is received, the WAN interface is considered healthy.




The same thing will happen with other WAN interface that it will be checked against the IP address types specified on the related page.

Now let us see what happen if at least one ping test doesn’t work.



if the ping test fail (i.e. all the echo replies isn't received), for at least one of the selected IP address type, the RV042 detects a fail and it stops sending data on that WAN interface.


That it means that from the last  check up the Elapsed time needed to detect a failed WAN is about  Retry timeout + T0.


Now  If I choose, on the “When fail”  option, “Remove the Connection”,  failover occurs and only the other WAN interface is used for all the packet.


If I’m using “Protocol Binding” it means that all the traffic bind on the failed WAN interface will start going through the other working WAN interface. E.g if I bind the ftp protocol on WAN2 interface and network service detection detect a fail on that interface(base on the IP address type selected) the new ftp session will use WAN1 to reach its destination (I say new session because the new session will use the IP address of WAN1 interface).

This ftp session will go through WAN1 until it is terminated even if WAN2, checked again its criteria, start work again.

That is fine for that ftp session, but I don’t know what it happens to a new ftp session that start after WAN1 is recovered and before the ftp session through WAN2 is terminated. I mean,which path is selected? the one specified on the bind rules  of  WAN1 interface or it follows again the failover rules (WAN2)?

please let me know if i 'm right and clarify where i haven't understood the topic

thanks in advance


Community Member

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Cisco Employee

Hello, Not sure if you had a



Not sure if you had a chance to review the below document:



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