Seems like your provider has configured HSRP. If it is true, then your description proves that the solution is working the way it is suppose to work.
In HSRP, two router acts as a virtual router and only the active router forward the traffic on behalf of the virtual router. Network clients send their packets to a virtual gateway, so there should not be a problem of duplicate packets.
Look at the following links to get more details on HSRP. Hopefully it will answer most of your questions.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.