Specifying and Configuring Routing Policies of Relative AS in RPSL

Routing policies specification language (RPSL) allows a network operator to specify routing policies at various levels in the Internet hierarchy, for example at the autonomous system (AS) level. At the same time, policies can be specified with sufficient detail in RPSL so that the low level router configurations can be generated from them. This paper is a discussion on using the RPSL to describe routing policies of relative AS in the Internet routing registry (IRR). We first analyze the relationships between a pair of ASes, and then explain how to specify various relative AS routing policies in RPSL. At last, we show an example of configuring routing policies using RtConfig that is a tool developed by the Routing Arbiter Project (RAP).

A study on IP-based hierarchical routing strategy in network simulation

The intrinsic routing policy of NS2—a network simulation tool— based on flat or hierarchical address has the disadvantage such as small topology scale,high resource consumption,low efficiency and so on.This paper proposes an IP based hierarchical routing strategy in network simulation to extend the topology scale and improve performance in simulating.Firstly,a stratification mechanism to identify IP address of nodes is described.Then,an algorithm of packet transmitting method(PTM) is presented for packet forwarding in the same subnet.Finally,algorithms of region partition(RP),routing computation based on region division(RCBRD) and routing distribution(RD) is proposed to implement regional segmentation,route calculation and route distribution for forwarding packets in different subnets respectively.The experiment results show that under the same condition,compared with plane address,the topology scale of the network simulation is extended two times and the consumption of time and memory during simulation is reduced by approximately 73%and 45.8% respectively.Compared with hierarchical address,the topology scale of the network simulation is expanded by more than 50%,and the consumption of time and memory is reduced by about 59.2% and 25% respectively.In addition,along with the growth of the node size,the proportion of reducing total simulation time and memory consumption would gradually increase.

ON OPTIMAL LOCAL BUFFER ALLOCATION IN FLEXIBLE MANUFACTURING SYSTEMS

An optimal design problem of local buffer allocation in the FMS is discussed in order to maximize a reward earned from processed jobs at all workstations. Structural properties of the optimal design problem are analyzed for the model with two job routing policies. Based on these properties, approaches to optimal solutions are given.

Toward software defined AS-level fast rerouting

Network failures are common on the Internet, and with mission-critical services widely applied, there grows demand for the Internet to maintain the performance in possibilities of failures. However, the border gateway protocol（BGP） can not react quickly to be recovered from them, which leads to unreliable packet delivery degrading the end-to-end performance. Although much solutions were proposed to address the problem, there exist limitations. The authors designed a software defined autonomous system（AS）-level fast rerouting（SD-FRR） to efficiently recover from interdomain link failures in the administrative domain. The approach leverages the principle of software defined networking（SDN） to achieve the centralized control of the entire network. By considering routing policies and BGP decision rules, an algorithm that can automatically find a policy-compliant protection path in case of link failure was proposed. The OpenF low forwarding rules are installed on routers to ensure data forwarding. Furthermore, to deactivate the protection path, how to remove flow entries based on prefixes was proposed. Experiments show that the proposal provides effective failure recovery and does not introduce significant control overhead to the network.