It is good question. Sometime it happens you need multiple network interfaces within the same container.
As far as I studied docker networking, pipework can help you to create multiple interfaces within the container.
Create a docker container using following command format:
sudo docker run -itd --name= --net=none
Add interfaces to the instantiated docker container:
sudo pipework bridge0 -i eth0 dhclient
sudo pipework bridge1 -i eth1 dhclient
Hope you can use these above commands to complete your task.