EQ-BGP: an efficient inter-domain QoS routing protocol

In this paper we propose the Enhanced QoS Border Gateway Protocol (EQ-BGP) aimed at performing the inter-domain QoS routing in a multi-domain IP network. The objective of EQ-BGP is to establish end-to-end paths that offer the most suitable QoS guarantees taking into account both the QoS capabilities of particular domains as well as inter-domain links. Thanks to this, the EQ-BGP supports providing of end-to-end QoS, what cannot be achieved with the aid of currently used BGP-4 protocol. Therefore, we enhance the existing BGP-4 protocol with four QoS components that are: (1) new path attribute conveying information about QoS capabilities of the path, (2) the QoS aggregation function used to calculate the path´s QoS capabilities based on contributions of particular domains and inter-domain links, (3) the QoS aware decision algorithm that allows us to select the best path fulfilling the QoS requirements, and (4) multiple routing tables that allow border routers to keep separate paths that are optimised for different QoS objectives. In the paper we provide description of the proposed EQ-BGP protocol and then we focus on performance evaluation corresponding to network convergence and protocol scalability. The obtained results say that EQ-BGP gives stable routing and its performance is at similar level as the BGP-4 protocol.