@@ -32,6 +32,28 @@ An image that has no parent is a **base image**.

 [boot2docker](http://boot2docker.io/) is a lightweight Linux distribution made

 specifically to run Docker containers. The boot2docker management tool for Mac and Windows was deprecated and replaced by [`docker-machine`](#machine) which you can install with the Docker Toolbox.

+## bridge

+

+In terms of generic networking, a bridge is a Link Layer device which forwards

+traffic between network segments. A bridge can be a hardware device or a

+software device running within a host machine's kernel.

+

+In terms of Docker, a bridge network uses a software bridge which allows

+containers connected to the same bridge network to communicate, while providing

+isolation from containers which are not connected to that bridge network.

+The Docker bridge driver automatically installs rules in the host machine so

+that containers on different bridge networks cannot communicate directly with

+each other.

+

+The default bridge network, which is also named `bridge`, behaves differently

+from user-defined bridge networks. Containers connected to the default `bridge`

+network can communicate with each other across the bridge by IP address but

+cannot resolve each other's container name to an IP address unless they are

+explicitly linked using the `--link` flag to `docker run`.

+

+For more information about Docker networking, see

+[Understand container communication](https://docs.docker.com/engine/userguide/networking/default_network/container-communication/).

+

 ## btrfs

 btrfs (B-tree file system) is a Linux [filesystem](#filesystem) that Docker