Pawel, EAPS does not impose a limitation in the number of nodes in a ring, but there are two factors that you should bear in mind:
- EAPS, being a ring topology, will survive to ONE failure. If a second failure occurs, you will lose connectivity. The larger the number of nodes (and links), the higher the probability of having two or more failures.
- When a failure is detected (or cleared) the Master switch will send a "Flush-FDB" message through the control vlan. When a Transit node receives this message it flushes its MAC table to relearn the new topology, and retransmits the message to the next switch in the ring. If you have a lot of switches in the ring, the time it takes for the ring to re-converge (that is, the time it takes for all the switches to flush their FDB and re-learn the topology) grows.
For me, the first factor is the most important, but the second should be considered if you need really fast convergence times.