In the context of an IP-over-ATM access and transport network, carrying guaranteed quality (CBR, rt-VBR) services as well
as IP datagrams (as ABR or UBR traffic classes), we consider the joint problems of Call Admission Control (CAC), bandwidth
allocation and routing. The presence of distributed access multiplexers is assumed, which are both geographically dispersed
(e.g., at the user premises) and hierarchically structured. Such multiplexers are intelligent devices with decision making
capabilities that operate jointly, in order to make the best possible use of the transport capacity of the access network
and to maintain the Quality of Service (QoS) requirements of different users and service classes. Following the physical system
organization, a hierarchical control structure is defined, where the admission of calls for real-time traffic classes (or
different users) is performed by independent controllers; the latter are parametrized by the bandwidths allocated by a common
link agent, playing the role of a “link coordinator” in the hierarchical control scheme. This decision maker aims at minimizing
a general cost that captures QoS requirements both at the call-level (call blocking probability) for QoS-aware, connection-oriented
services and at the cell-level (cell loss probability) for connectionless, best-effort, ones. The control architecture also
reflects the multilayer hierarchy introduced by the presence of multiple teletraffic time scales, by essentially decoupling
the above problem from that of ensuring QoS at the cell-level for services of the first type. We derive the optimal parameters’
setting from the numerical solution of a mathematical programming problem. Then, the same structure is applied to link multiplexers
of the transport network nodes, which are supposed to possess both ATM and IP switching/routing capabilities. Routing strategies
at both ATM and IP levels are defined, which are combined with the above described CAC and bandwidth allocation scheme. The
performance of the whole structure is tested by simulation.