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.