Measurements of Multicast Service Discovery in a Campus Wireless Network

Applications using multicast service discovery protocols, such as iTunes, have become increasingly popular. However, multicast service discovery protocols generate significant network traffic overhead, especially in a wireless network. We measure and analyze the traffic of one of the most widely deployed multicast service discovery protocols, DNS-SD/mDNS, in a campus wireless network where a single multicast domain serves a large number of users. We define three service discovery models which correspond to different service discovery behaviors. We compare these three models in terms of packet overhead and service discovery delay for different network sizes and service lifetime assumptions. The measurement shows that mDNS traffic consumes about 13 percent of the total bandwidth of the network.