Enterprise users generally have very basic requirements compared to Service Providers customers. Instead of providing Ethernet-based services, they are consuming Ethernet-based services. This means that each port is connected to a host or providing a trunk to another switch.
Because of the simplicity of these requirements, it wouldn’t be fair to enforce the same configuration. Instead, the Juniper MX provides an Enterprise-style interface configuration that provides basic bridging functionality with a simplified configuration.
Some of the obvious drawbacks of a simplified configuration are the loss of advanced features like VLAN normalization. But the big benefit is that you no longer have to worry about the different VLAN tagging or encapsulation options. When you commit a configuration, Junos will automatically walk the interface tree and look for IFLs using the Enterprise-style interface configuration and determine what VLAN tagging and encapsulation options are needed.
The icing on the cake is that you no longer have to specify which bridge domain each interface belongs to; this happens automatically on commit, but it doesn’t actually modify the configuration. Junos will walk the interface tree and inspect all of the Enterprise-style IFLs, look and see which VLAN IDs have been configured, and automatically place the IFLs into the matching bridging domain. Now you can see why advanced VLAN normalization isn’t possible.
The Enterprise-style ...