Reprovisioning for latency-aware dynamic service chaining in metro networks

Abstract

To support new emerging and highly-dynamic 5G services, optical metro networks must be capable of provisioning services on the fly. Network Function Virtualization (NFV) is leveraged to fulfill these dynamic service demands by placing Virtual Network Functions (VNFs) in NFV-capable network nodes and chaining them together ("service chaining"). In addition, new 5G service chains often have bandwidth requirements with sub-wavelength granularity making traffic grooming essential for efficient network resource utilization. However, the latency requirement for these services will not allow to always perform traffic grooming, as grooming operations add non-negligible latency to traffic, and this might lead to poor utilization and high service blocking. Thus, it is important to investigate dynamic solutions to increase network utilization and decrease service blocking. One approach to achieve this goal is to re-provision Service Chains (SCs) to use network resources as efficient as possible. Re-provisioning consists in tearing down a service chain and re-allocate its resources, typically with the intent to make room for new chains that would be otherwise rejected. While traditional re-provisioning entailed only routing re-assignment, re-provisioning of SCs entails both rerouting traffic and/or relocating VNFs, hence originating new research problems. In this paper we propose new heuristic algorithms to re-provision SCs whenever a service cannot be provisioned. We provide two different approaches to perform re-provisioning, namely bandwidth and location re-provisioning. While bandwidth re-provisioning consists of modifying only bandwidth assignment of SCs, location re-provisioning considers the possibility of changing the nodes each SC is mapped to. We also considered two different optical network architectures. Results obtained on realistic network topology and services show that location re-provisioning allows to achieve up to 28% improvement in terms of number of SCs we are able to provision in the network.

C to C+L Bands Upgrade with Resource Re-provisioning in Optical Backbone Networks

“…Thus, we investigate pro-active re-provisioning of lightpaths to C+L bands after each upgrade for cost benefit. Prior works show benefits of lightpath re-provisioning for restorability of optical mesh networks [3,4], network capacity maximization [5], service chaining in optical metro networks [6], etc. But, to the best of our knowledge, our work is the first to study the benefits of lightpath re-provisioning during upgrade to C+L bands.…”