Multimedia communication services are being made available with the advent of broadband optical fiber networks. As many different services will be accommodated in such networks, network survivability has been recognized to be a crucial concern. In this paper, we propose a new restoration algorithm for ATM networks providing multimedia services. Our proposed restoration algorithm adopts the message bundling scheme of the Multi-Destination Flooding (MDF) algorithm which was previously proposed for STM-based networks to handle catastrophic failures such as multiple link and node failures. Virtual Paths (VP) with the same communication speed are bundled and Operation Administration and Maintenance (OAM) cells are used for communication of restoration messages. In addition, the following modifications are made on the original MDF to improve restoration performance. The pre-cancellation scheme is adopted to arbitrate reservation contention to realize high restoration ratio. The dual queue scheme is applied to avoid congestion of restoration messages. Moreover, the connection control scheme for VPI connections is proposed to prevent alternative routes from being misconnected. This paper describes the design concept of our restoration algorithm, processes in each restoration phase, and the performance evaluation by computer simulation.

The IETF Differentiated Services (DiffServ) framework achieves scalability by (1) aggregating traffic flows with coarse grain QoS on the data plane, and (2) allocating network resources with a bandwidth broker (BB) on the control plane. However, there are many issues that need to be addressed under such framework. First, it has been shown that the concatenation of strict priority (SP) scheduler of class-based queues (CBQ) can cause delay jitter unbounded under certain utilization, which is not acceptable to support the premium service (PS). Furthermore, it is not clear how such a DiffServ network can support traffic flows requiring the guaranteed service (GS), which is a desirable feature of the future Internet. This paper presents architecture and mechanisms to support multiple QoS under the DiffServ paradigm. On the data plane, we present a node architecture based on the virtual time reference system (VTRS). The key building block of our node architecture is the core-stateless virtual clock (CSVC) scheduling algorithm, which, in terms of providing delay guarantee, has the same expressive power as a stateful weighted fair queueing (WFQ) scheduler. With the CSVC scheduler as our building block, we design a node architecture that is capable of supporting integrated transport of the GS, the PS, the assured service (AS), and the traditional best effort (BE) service. On the control plane, we present a BB architecture to provide flexible resource allocation and QoS provisioning. Simulation results demonstrate that our architecture and mechanisms can provide scalable and flexible transport of integrated traffic of the GS, the PS, the AS, and the BE services.

The Telecommunications Management Network (TMN) is a major focus of telecommunications operations work in the 1990s. New telecommunication equipment is required to conform to the TMN standards. In the TMN, a network element is managed as a set of Managed Objects (MOs). The MO program has to be executed in a muiltithreaded, parallel environment for a quick response; therefore, concurrency control is a key issue for developing an MO program. This paper proposes a formal definition to specify data for concurrency control to improve the correctness and reusability of the specification. The definition is based on a Generic Relationship Model (GRM). By using the formalized definition and developing an algorithm to translate the definition into executable code, concurrency control is performed without coding. After describing the algorithm used to perform concurrency control, this paper discusses a three-layer concurrency control architecture to accommodate this framework efficiently.