I have face an interesting problem, I have a ADSL modem and I configured it in bridge mode. And then I configured the Cisco UC520 with a PPPOE connection and it is connected to the internet.
I also use the Cisco UC520 as a NAT device to internal Lan users.
I checked the internet from one of internal clients and I found that it is not good at all. the web sites are not brows and the ping is fluctuating between 200 and 1400 ms.
When I configure the PPPOE on the modem and use the IP address of the modem as a default gateway of all lan devices, it will work fine.
I am wondering why modem in bridge mode is not working properly, I prefere to get the public IP address in my UC device. now I have to use the modem as the NAT device.