Update notes on scaling, add notes on links + modes

Signed-off-by: Aanand Prasad <[email protected]>

docs/networking.md

@@ -43,7 +43,23 @@ If any containers have connections open to the old container, they will be close
 
 ## Scaling services
 
-If you create multiple containers for a service with `docker-compose scale`, each container will join the network with the same name. For example, if you run `docker-compose scale web=3`, then 3 containers will join the network under the name `web`. Looking up the name `web` will return the IP address of one of them, but Docker and Compose do not provide any guarantees about which one.
+Scaling is currently not fully functional. If you create multiple containers for a service with `docker-compose scale`, one container will join the app's network under the service name and the others will join under different names.
+
+This limitation will be addressed in a future version of Compose, where a load balancer will join under the service name and load balance between the service's containers in a configurable manner.
+
+## Links
+
+Docker links are a one-way, single-host communication system. They should now be considered deprecated, and you should update your app to use networking instead. In the majority of cases, this will simply involve removing the `links` sections from your `docker-compose.yml`.
+
+However, links will continue to work - they just won’t work across multiple hosts. If an app has any services with `links` defined, Compose will use the `bridge` driver for the app’s network. It will continue to work exactly as it used to. If you deploy the app to a Swarm, containers which are linked to one another will be scheduled on the same node.
+
+## Custom container network modes
+
+Compose allows you to specify a custom network mode for a service with the `net` option - for example, `net: "host"` specifies that its containers should use the same network namespace as the Docker host, and `net: "none"` specifies that they should have no networking capabilities.
+
+If a service specifies the `net` option, its containers will *not* join the app’s network and will not be able to communicate with other services in the app.
+
+If *all* services in an app specify the `net` option, a network will not be created at all.
 
 ## Configure how services are published