Before discussing bridging, a closer look at how Junos handles interfaces is required. Bridging on the MX is fundamentally different than on the EX due to the types of challenges being solved. As you move into the finer points of bridging and virtualization within the MX, it’s critical that you have a clear understanding of how interfaces are created and applied within bridge domains, routing instances, and other features.
Let’s take a look at a single, generic interface that supports multiple units, families, and addresses in Figure 2-5.
Figure 2-5. Junos interface hierarchy
This represents the physical interface such as xe-0/0/0. This is the root of the hierarchy and all other components are defined and branched off at this point. Features such as maximum transmission unit (MTU), link speed, and IEEE 802.3ad are configured at this level.
The IFL simply defines a unit number under the IFD such as xe-0/0/0.0 or xe-0/0/0.1. Regardless of the configuration, at least a single unit is required. A common example of multiple IFLs are VLAN ID when using IEEE 802.1Q.
Each IFL needs an address family associated with it, as Junos
supports multiple protocols. Common examples include
inet for IPv4,
inet6 for IPv6, and
iso when configuring the IS-IS routing
Finally, each IFF needs some ...