Makeup of the Internet (as of 1992)

• 100 countries (counting email connectivity)
• 39,000 networks
• 1,000,000 hosts
• 5,000,000 users
• Growing rapidly

Participating Networks

• NSFNET
  • Hierarchical (network of networks)
  • Major research/education component
  • Campuses, Companies, K-12
• MILNET
  • Split off from ARPANET in 1984
  • DDN NIC manages root domain of DNS, issues IP addresses
• NASA Science Internet
  • Space Physics Analysis Network (SPAN; DECnet)
  • NASA Science Network (NSN; TCP/IP)
• DOE

Other Networks with Connections to Internet

• BITNET ("Because It's Time"; NetNorth in Canada, EARN in Europe)
• ESnet (DoE energy science; HEPnet, MFEnet)
• FidoNet (dialup, personal computers)
• Usenet (dialup UUCP, overlap with Internet)
• FreeNets (National Public Telecomputing Network): example: freenet-in-a.cwru.edu information: info@nptn.org

International Connectivity (Krol, '92)

          Minimal Widespread Expected Other     TOTAL
BITNET      19        28         1                48
INTERNET              40         5                45
UUCP        46        44        11               101
FIDONET     12        47                7         66
OSI          9        16                          35

International Connectivity Map, by Connection Type (Landwehr)