Configuring an IP Demultiplexing Interface

To configure a demux interface, include the following statements at the [edit interfaces] hierarchy level:

[edit interfaces]interface-name {unit logical-unit-number {... logical-interface-configuration ...}}demux0 {unit logical-unit-number {demux-options {underlying-interface interface-name;}family family {demux-destination {destination-prefix;}demux-destination {source-prefix;}mac-validate (loose | strict)unnumbered-address interface-name <preferred-source-address address>;}}}

Keep the following guidelines in mind when configuring the demux interface:

Demux interfaces are supported on M120 or MX Series routers only.
You can configure only one demux0 interface per chassis, but you can define logical demux interfaces on top of it (for example, demux0.1, demux0.2, and so on).
You must associate demux interfaces with an underlying logical interface.
Note: IP demux interfaces currently support only Gigabit Ethernet, Fast Ethernet, 10-Gigabit Ethernet, and aggregated Ethernet underlying interfaces.
The demux underlying interface must reside on the same logical system as the demux interfaces that you configure over it.
IP demux interfaces currently supports the Internet Protocol version 4 (IPv4) suite inet and Internet Protocol version 6 (IPv6) suite inet6 family types.
You can configure more than one demux prefix for a given demux unit. However, you cannot configure the exact same demux prefix on two different demux units with the same underlying interface.
You can configure overlapping demux prefixes on two different demux units with the same underlying prefix. However, under this configuration, best match rules apply (in other words, the most specific prefix wins).
If the address in a received packet does not match any demux prefix, the packet is logically received on the underlying interface. For this reason, the underlying interface is often referred to as the “primary” interface.