Topology Abstraction Service for IP-VPNs

Abstract

VPN service providers (VSP) and IP-VPN customers have traditionally maintained service demarcation boundaries between their routing and signaling entities. This has resulted in the VPNs viewing the VSP network as an opaque entity and therefore limiting any meaningful interaction between the VSP and the VPNs. The purpose of this research is to address this issue by enabling a VSP to share its core topology information with the VPNs through a novel topology abstraction (TA) service which is both practical and scalable in the context of managed IP-VPNs. TA service provides tunable visibility of state of the VSP's network leading to better VPN performance. A key challenge of the TA service is to generate TA with relevant network resource information for each VPN in an accurate and fair manner. We develop three decentralized schemes for generating TAs with different performance characteristics. These decentralized schemes achieve improved call performance, fair resource sharing for VPNs, and higher network utilization for the VSP. We validate the idea of the VPN TA service and study the performance of the proposed techniques using various simulation scenarios over several topologies.