Constructing inter-AS power shortest protection TE-LSPs using BGP
draft-mjsraman-rtgwg-inter-as-psp-protect-02

Abstract

In this paper, we propose a framework to build protection / backup paths for power shortest primary inter-AS TE-LSPs. The primary path is built within a framework to reduce the aggregate power consumption of the Internet using a collaborative approach between Autonomous Systems (AS). We identify the low-power paths among the AS and then use Traffic Engineering (TE) techniques to route the packets along the paths. Such low-power paths can be identified by using the consumed-power-to-available-bandwidth (PWR) ratio as an additional constraint in the Constrained Shortest Path First (CSPF) algorithm. For re-routing the data traffic through these low-power paths, the Inter-AS Traffic Engineered Label Switched Path (TE-LSP) that spans multiple AS can be used. Once the primary paths have been built we use the same techniques to build backup power shortest paths in a similar manner except by excluding the nodes (ASes) and links (between these ASes) that are present in the primary path. This way the backup path does not traverse any of the ASes or links between these ASes of the primary path so constructed. Extensions to the Border Gateway Protocol (BGP) can be used to disseminate the PWR ratio metric among the AS thereby creating a collaborative approach to reduce the power consumption. Since calculating the low-power paths can be computationally intensive, a graph-labeling heuristic is also proposed. This heuristic reduces the computational complexity but may provide a sub-optimal low-power path. The feasibility of our approaches is illustrated by applying our algorithm to a subset of the Internet. The techniques proposed in this paper for the Inter-AS power reduction require minimal modifications to the existing features of the Internet. The proposed techniques can be extended to other levels of Internet hierarchy, such as Intra-AS paths, through suitable modifications.

Authors

Shankar Raman
Balaji Venkat Venkataswami
Gaurav Raina
Vasan Srini

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