SDN and NFV Simplified: A Visual Guide to Understanding Software Defined Networks and Network Function Virtualization

29. Service Chaining

When reading about software-defined network (SDN), the phrase service chaining comes up a lot, and it is not initially clear what relevance the term has to SDN. Service chaining, after all, is nothing new; it’s been around in networks for some time, and it relates to the way hardware, typically security appliances, were attached to one another to form a physical chain of devices that provided the combined functions, which you required. For example, you may have wanted Network Address Translation (NAT), followed by intrusion detection (IDS) and then antivirus (AVS), followed by URL and content filtering and a firewall (FW). If that were the case, the network administrators would build these appliances and see to it that they ...