Service Function Chaining with Deterministic Fault Tolerance in Optical
Edge Networks
Abstract
In the upcoming 5G-and-beyond era, ultra-reliable low-latency
communication (URLLC) services will be ubiquitous in edge networks. To
improve network performance and quality of service (QoS), URLLC services
could be delivered via a sequence of software-based network functions,
also known as service function chains (SFCs). Towards reliable SFC
delivery, it is imperative to incorporate deterministic fault tolerance
during SFC deployment. However, deploying an SFC with deterministic
fault tolerance is challenging because the protection mechanism needs to
consider protection against physical/virtual network failures and
hardware/software failures jointly. Against multiple and diverse
failures, this work investigates how to effectively deliver an SFC in
optical edge networks with deterministic fault tolerance while
minimizing wavelength resource consumption. We introduce a protection
augmented graph, called k-connected service function slices
layered graph (KC-SLG), protecting against k-1 fiber link
failures and k-1 server failures. We formulate a novel problem
called deterministic-fault-tolerant SFC embedding and propose an
effective algorithm, called most candidate first SF slices layered graph
embedding (MCF-SE). MCF-SE employs two proposed techniques:
k-connected network slicing (KC-NS) and k-connected
function slicing (KC-FS). Through thorough mathematical proof, we show
that KC-NS is 2-approximate. For KC-FS, we demonstrate that
k = 3 provides the best cost-efficiency. Our experimental results
also show that the proposed MCF-SE achieves deterministic-fault-tolerant
service delivery and performs better than the schemes directly extended
from existing work regarding survivability and average cost-efficiency.