Retrospective on fragmentation considered harmful

We look back at our 1987 paper, "Fragmentation Considered Harmful," to explain why we wrote it, how the prevalence of fragmentation was reduced by approaches such as Path MTU Discovery, and how fragmentation-related issues still lurk in today's Internet. Our paper listed several reasons why we thought fragmentation was harmful; some were more true in 1987 than they are today, and after our paper was published, the community realized that fragmentation (and the mechanisms used to mitigate it) exposed harms we did not anticipate in our paper.