The invention discloses distributed communication equipment architectures and techniques. A host system includes an expansion unit through which control information and communication traffic may be exchanged with an expansion system. The expansion system is thereby controllable by a controller at the host system, significantly simplifying the design and reducing the cost of the expansion system. The expansion unit for a host system may also provide one or more configurable communication link interfaces. Each configurable interface may be independently configured as a network-side interface for connection to upstream communication equipment or as an access-side expansion interface for connection to an expansion system, allowing provisioning of network and access interfaces at the host system as needed.