Rethinking Homing Architectures

As the pressure to drive down network costs increases without compromising the stringent availability requirements imposed by service Level Agreements (SLAs), the development of advanced techniques to optimize the interaction between network layers becomes a necessity. To this end multi-layer networks have been investigated, influencing network design and provisioning. The requirements of high quality of service (QoS) lead to the elimination of single points of failure (SPoF). As a consequence, network elements and connections are often duplicated. The interconnection of core networks with metro/access networks becomes crucial, resulting in the attachment of services at two different network elements. This redundancy, which is introduced through such configurations, opens the path for investigation of resource efficient homing architectures, where homing is defined as the interconnection of an access router to a core router. To this end alternative homing architectures to traditional dual homing are studied under a multi-layer point of view, in order to capture the occurring interactions. We focus on the arising network equipment costs and the resulting availability conducting case studies highlighting the occurring trade-offs. It is shown that significant savings in capital expenditures (CAPEX) can be obtained by deploying a shared router strategy, while the availability reduction is quantified. Homing architectures have been discussed in [1] [3].