The WAN IP tells the client where is the VPN server. When the second WAN IP works, the client will lose his way.

Hi Westhaddon, ER5120 is a Gigabit loadbalance router, and it NAT passthrough is 350Mbps.

Perhaps, you can try the Online Detection function.

Could you please describe the problem more specifically? What did the log of the ER5120 say? Did the ADSL LED light on or flash when it did not work?

OMG, the TL-SF1024D does not even have SFP slot! How can it work with SM311LM?

Hi, I think the MC112CS can not achieve your purpose. MC112CS can only translate optical signal and electric signal in Ethernet network, that is to say it supports EPON only. But you can use the ZTE...