In this paper we study energy conservation in the Internet. We observe that different traffic volumes on a link can result in different energy consumption; this is mainly due to such technologies as trunking (IEEE 802.1AX), adaptive link rates, etc. We design a green Internet routing scheme, where the routing can lead traffic in a way that is green. We differ from previous studies where they switch network components, such as line cards and routers, into sleep mode. We do not prune the Internet topology. We first develop a power model, and validate it using real commercial routers. Instead of developing a centralized optimization algorithm, which requires additional protocols such as MPLS to materialize in the Internet, we choose a hop-by-hop approach. It is thus much easier to integrate our scheme into the current Internet. We progressively develop three algorithms, which are loop-free, substantially reduce energy consumption, and jointly consider green and QoS requirements such as path stretch. We further analyze the power saving ratio, the routing dynamics, and the relationship between hop-by-hop green routing and QoS requirements. We comprehensively evaluate our algorithms through simulations on synthetic, measured, and real topologies, with synthetic and real traffic traces. We show that the power saving in the line cards can be as much as 50 percent.

Ternary Content Addressable Memory(TCAM)-based multidimensional tables are widely used to implement Access Control Lists (ACLs) for Internet packet classification and filtering, and have also become attractive for constructing the forwarding tables of Internet routers and the flow tables of Openflow switches, where multiple fields are generally used to match incoming packets. However, as such tables can grow quickly as the Internet develops fast, and sometimes even expand in size because of TCAMs limitation in storing rules with range fields, it becomes imperative to compress these tables. In this paper, we propose a fast and efficient approach to multidimensional table compression. We divide the multidimensional space iteratively to obtain a series of cells, and then combine those cells that are associated with the same action. Our approach applies to tables of any dimension, addresses the range expansion problem, and provides efficient compression for TCAM-based tables. The experiments show that our approach has low computing cost in time, which is significant for the online update of tables. On average, it reduces 23.0% entries of the real-life ACLs, 25.8% to 55.1% of the generated two-dimension tables, 55.1% of the generated ACLs, and 28.4% of the generated Openflow flow tables.

In this paper, we gather the weekly reports of an operational IP backbone network from January 2006 to January 2013, according to which, we can restore the truth and uncover the evolution of network configurations of the studied network. Our high-level analyses illustrate that rate limiting and launching routes for new customers are most frequently configured. We can identify and construct configuration templates by correlating each task to a certain set of commands in configuration files, based on which, automated configuration provisioning for an operational backbone network is feasible. In addition, we can configure redundant links for those with higher rate of failures according to our detailed analyses of link failures, which will enhance the stability and reliability of data transmission.

In this paper we study energy conservation in the Internet. We observe that different traffic volumes on a link can result in different energy consumption; this is mainly due to such technologies as trunking (IEEE 802.1AX), adaptive link rates, etc. We design a green Internet routing scheme, where the routing can lead traffic in a way that is green. We differ from previous studies where they switch network components, such as line cards and routers, into sleep mode. We do not prune the Internet topology. We first develop a power model, and validate it using real commercial routers. Instead of developing a centralized optimization algorithm, which requires additional protocols such as MPLS to materialize in the Internet, we choose a hop-by-hop approach. It is thus much easier to integrate our scheme into the current Internet. We progressively develop three algorithms, which are loop-free, maximize energy conservation, and jointly consider green and QoS requirements such as path stretch. We comprehensively evaluate our algorithms through simulations on synthetic and real topologies and traffic traces. We show that the power saving in the line cards can be as much as 50%.

Traditional IP multicast in a network domain is likely to imply a huge burden of storage and forwarding for routers and it's hard to support quality of service. The recent proposed application layer multicast is more scalable but increases traffic load and end-to-end delay. In the paper, we make multicast supporting comparable multi-class services on the overlay network comprising only edge routers. Considering resource limitation on the router and multi-class services by the member, the problem to build minimum cost trees is NP-hard, so we design three feasible heuristic algorithms to solve it. Extensive simulations are conducted to evaluate the performance of the proposed heuristics and validate the effectiveness of reducing the total tree cost and iteration times under considered constraints. The proposal is expected to combine with DiffServ or MPLS VPN networks to fulfill multi-class QoS multicast.

Traditional IP multicast suffers from forwarding state scalability problems as the number of concurrent active multicast groups increases. The problem is exacerbated when provisioning QoS since additional information of resource requirement from members must be kept at routers. In this paper, we firstly consider the comparability between various QoS levels and propose a modularized QoS multicasting approach in the DiffServ model. To achieve the multicast state scalability, the trees, called common trees, are decoupled from groups. The groups including the members requiring heterogeneous QoS are divided into subgroups and delivered through the common homogeneous QoS trees. We put forward a tree-choosing algorithm to find out appropriate trees for a group. Extensive simulations demonstrate that the approach is able to improve multicast forwarding state scalability as well as supporting different QoS requirement. The modularized approach can be considered a building block for QoS multicasting in the DiffServ architecture for its ease of deployment and compatibility with DiffServ