A Dial Access Stack Architecture (DASA) includes a stack of Network Access
Servers (NASs) each independently establishing and processing information
for communication links on a public telephone network. A primary
interconnect couples the stack of network access servers together through
a primary network. A routing engine is coupled through the primary
interconnect to the stack of network access servers routing packets
between the network access servers and an Internet network. A secondary
interconnect couples the stack of network access servers together through
a secondary network that operates independently of the primary
interconnect. The primary or secondary interconnects each allow pairs of
the network access servers to communicate with each other in parallel and
independently of the routing engine. The DASA provides scalability and
resiliency to fault conditions and can easily aggregate and integrate any
new access media. Applications such as voice, video and multicasting can
be seamlessly added. The DASA architecture can scale from hundreds to
thousands of ports at optimal cost and performance while avoiding any
single point of failure.