Attila Bader

A practical method for the efficient resolution of congestion in an on-path reduced-state signalling environment

Currently, the standardisation of on-path signalling protocols is going on within the Next Steps in Signalling (NSIS) Working Group of the IETF. NSIS is responsible for the definition of a general IP signalling protocol. The first use case of the proposed protocol is flow-level resource management. One of the considered reservation methods, reduced-state mode, is based on the Resource Management in DiffServ (RMD) framework. Since it relies only on per-class state information in interior routers, it has a number of benefits including scalability, low complexity, and low memory consumption. However, the price of simplicity is decreased efficiency in case of exceptional situations. The most demanding task for RMD is the handling of congestion that may occur after a failure resulting in re-routing of flows onto a new path. Resolving a suddenly evolved overload without per-flow states is a highly non-trivial task. We present a low complexity mechanism which easily handles the undesirable situation, and we give guidelines to set the parameters of our scheme based on worst-case calculations.

QoS signaling across heterogeneous wired/wireless networks: resource management in DiffServ using the NSIS protocol suite

Reservation-based quality of service (QoS) in a mixed wireless and wireline environment requires an end-to-end signaling protocol that is capable of adapting to the idiosyncrasies of the different networks. The QoS NSIS signaling protocol (QoS-NSLP) has been created by the Next Steps In Signaling working group at the IETF to fulfill this need for an adaptive reservation protocol. It allows reservation requests to be interpreted by equipment implementing different QoS models along the path between a data sender and a data receiver. This paper describes the QoS-NSLP, and an example of a particular QoS model that is based on resource management in DiffServ (RMD). RMD provides a scalable dynamic resource management method for DiffServ networks. RMD has two basic functions to control the traffic load in a DiffServ domain: it provides admission control for flows entering the network and it has an algorithm that terminates the required amount of flows in case of congestion caused by failures (e.g. link or router) within a DiffServ domain. The admission control within the domain can be either measurement - or reservation-based. The basic signaling mechanism is described for different signaling scenarios and the expected performance of the protocol is discussed

Using IP as transport technology in third generation and beyond radio access networks

This paper discusses the motivation for developing a new QoS signaling protocol for IP-based Radio Access Networks. It describes the main characteristics of these networks and the special requirements imposed by these characteristics on QoS signaling solutions.