Arrangement of Prioritized LSP in MPLS Networks

Y.-W. Chen and J.-C. Huang (Taiwan)


QoS, MPLS, Label Switch Path


The Multi-Protocol Label Switch (MPLS) adopts the explicit arrangement of routing paths and the fast forwarding of labeled packets to improve the network throughput. However, the performance of the network, especially when the quality of services (QoS) is considered, will also be affected if the label switch paths are not well arranged. Basically, the network resource shall be carefully allocated to the label switch paths (LSP) so that the throughput can be increased. And from the link point of view, the capacity of a specific link shall not be mostly allocated for the high priority LSP because it will cause the inflexibility in the scheduling process. In this paper, the Best-fit Shortest Path (BSP) assignment and the Worst Shortest Path (WSP) assignment schemes are proposed for the arrangement of label switch paths. In order to provide the flexibility in packet scheduling, we propose that the BSP scheme is applied for the allocation of low priority LSP and the WSP scheme is used for the arrangement of LSP with high priority. Furthermore, the elastic constrained bandwidth allocation scheme is proposed to prevent the link bandwidth from being occupied by the high priority LSP. The experimental results indicate that, when comparing with the BSP scheme, the WSP scheme can allocate more LSP. And the minimum cut approach is helpful for the BSP scheme, however, it is not sensitive to WSP scheme. Moreover, the proposed elastic constrained bandwidth allocation scheme demonstrates a quite good performance in smoothing the link utilization of high priority LSP.

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