This paper describes the implementation of a processorgroup membership protocol in an experimental real-time network. The protocol is appropriate for fault-tolerant distributed systems using TDMA for scheduling messages. It allows nodes to maintain a consensus on the operational state of all nodes, in the presence of node failures and restarts, as well as network failures. The protocol is based on the principle that, in a system of n nodes, each node must acknowledge the messages from k other nodes in the membership group, where k can assume values between 2 and n 1. Membership agreement is guaranteed if f k 1 failures occur during n consecutive transmission slots. We have implemented the membership protocol in a time-triggered network based on COTS Ethernet hardware, programmed to schedule messages according to the TDMA method.