Change in Continuity: Chaining Services With an Augmented IGP

Abstract

Ever since Network Functions Virtualization has replaced dedicated appliances, ISPs have been able to add a degree of flexibility in their traffic engineering. Now traffic is steered through virtual functions before reaching its destination, which, nonetheless, hardens network operation. Insofar, a logically centralized approach has been proposed to compute and install the correct forwarding behavior on every network devices. However, this flexibility comes at the cost of increased fragility compared to current Interior Gateway Protocols (IGP) and of a whole new infrastructure. Instead, we propose to augment the routing layer with the notion of services. Our solution leverages on existing distributed routing protocols where, in addition, autonomous nodes announce information about the virtual services they provide. Our design is modular, incrementally deployable and has been implemented in what we call an NFV Router. In our evaluation, we show that (i) NFV Routers distributed chaining decisions are close to optimal centrally-computed paths, (ii) on a large scale testbed deployment, NFV Routers efficiently steer traffic through chains and only add a small overhead to control traffic, and (iii) our distributed system, because of its local control loop, has a faster reaction to network events than centralized solutions.