We pick i.root-servers.net, one of the 13 root servers (1), and ask it about expansion.sm and learn that sm is delegated to four name servers (2), so we ask ns3.telecomitalia.sm where we learn that expansion.sm is delegated to two name servers, including dns.intelcom.sm (3), so we ask that one and get the following answer:
Expansion.sm is a domain controlled by two domain name servers at omniway.sm and intelcom.sm. Both are on the same IP network. Incoming mail for expansion.sm is handled by two mail servers at expansion.sm themselves. Both are on the same IP network.