Lost in Fat Tree forest and route out

Speakers:
Rafal Szarecki, Juniper Networks

Clos and Fat-Tree have gained prominence in today's networking, primarily as a result of a the paradigm shift towards a centralized data-center based architecture that is poised to deliver a majority of computation and storage services in the future. The existing set of dynamic routing protocols was geared originally towards a network with an irregular topology and low degree of connectivity and consequently several attempts to adapt those have been made in order to enable CLOS/FatTree Fabrics. In looking at the problem through the very lens of its requirements an optimal approach does not seem to be a simple modification of either a link-state (distributed computation) or distance-vector (diffused computation) approach but rather a mixture of both, colloquially best described as 'link-state towards the spine' and 'distance vector towards the leafs'. This session will describe prionciple of novel routing protocol - RIFT (draft-przygienda-rift-01) - targeted for CLOS/FatTree topologies. The techical motivation for new protocol as well techniques used to overcome limitation of BGP and ISIS/OSPF would be discussed.