The old code uses a timer(1, .., because the author has decided, that the router solicitation has to be send once a second after boot and and after that in a 10 second intervall (as the comment suggested). The original code was inlined into periodic process and checked the *local* variable counter this calculate the intervals. A timer(1.., was completely unnecessary here. timer(50, and the additonal counter does exactly what the original author has intended with his comment.