The thing to remember is that just because dev has decided to leverage microservices does not in turn mean that the network somehow magically becomes microsegmented or that if microsegmentation is used to optimize the network service architecture that suddenly apps become microservices. Microsegmentation can be used to logically isolate monolithic applications as easily as it can microservices.
“Micro is big these days” - The below statement is from an article showing the similarities and differences between microservices and microsegmentation. Of course we all know the differences, but we might have never thought about the similarities between the two approaches.
Microservices are about dissecting applications to smaller units and run those units independently instead of running them in a monolithic application. This creates the ability to decouple those functions and makes the service more scalable, independent from the other services and easier to maintain a single functionality. Often one team is responsible for one microservice.
Microsegmentation is about transforming the network into smaller units and controlling access to those smaller units (called segments) in different granularities down to the process or even user level. It can also decouple segmentation (for security) from using the network infrastructure and making it independent of the underlying architecture.
I like the approach the article suggests, cohabitation, both approaches can and should coexist. Just because you use one or the other does not mean you are achieving both.
