QoS Routing Mechanisms and OSPF Extensions

Abstract

This memo describes extensions to the OSPF [Moy98] protocol to support QoS routes. The focus of this document is on the algorithms used to compute QoS routes and on the necessary modifications to OSPF to support this function, e.g., the information needed, its format, how it is distributed, and how it is used by the QoS path selection process. Aspects related to how QoS routes are established and managed are also briefly discussed. The goal of this document is to identify a framework and possible approaches to allow deployment of QoS routing capabilities with the minimum possible impact to the existing routing infrastructure.In addition, experience from an implementation of the proposed extensions in the GateD environment [Con], along with performance measurements is presented.

Next Steps in Signaling (NSIS): Framework

“…It has been proposed for a number of routing protocols, such as OSPF [16] and others. In general, load sharing means that packet forwarding will take into account header fields in addition to the destination address; a general discussion of such techniques and the problems they cause is provided in [17].…”

Algorithms and protocols for stateless constrained-based routing

“…OSPF, BGP) [3,5,15,17,49]. Several recent studies have acknowledged the need for scalable QoS routing solutions [4,11,27,29,48] and have given the stimulus for a number of proposals on how to integrate QoS routing into a Differentiated Services (DiffServ) framework [21,24,43].…”

“…Nonlinear quantization techniques such as the ones suggested in Ref. [5] can be used for this purpose. In Ref.…”

“…In brief, the encoding in Ref. [5] is done as follows. The 16-bit TOS field is divided into a mantissa part (13 bits) and an exponent part (3 bits).…”

“…An appropriate base is chosen for the exponent (in Ref. [5] the authors suggested using base 8 for bandwidth and base 4 for delay). A bandwidth (or delay) value is then expressed using scientific notation.…”