Internet, Intranet and Extranet

• The Internet: a network of networks servicing the users worldwide

• Intranet: an organization's private network that uses Internet technology

• Extranet: The intranet that some of its functions are accessible to the organization's business partners

The Internet• Three aspects of the Internet

evolution– Capacity growth– Application and traffic growth– Internet policy change

Internet CapacityARPANET (1969): The Internet was started by the U.S. Department of

Defense as a network of four computers.- 1974, 62 hosts- 1983, 1000 hosts- 1989, decommissioned

NSFNET (1986): Built up by National Science Foundation with a 3-tier structure- 1987, 10,000 hosts in the Internet, 1000 in BITNET- 1988, upgraded to T1 (1.544 Mbps). - 1991, upgraded to T3 (45Mbps)- 1995, decommissioned

vBNS (1995): 622Mbps in 1995vBNS+ (now): 2.5 Gbps (or more)

NSFNET

By 1991, the NSFNET's backbone network service has been upgraded to T3 (45 Mbps) links

Internet Policy and deregulations

Originally, commercial traffic was forbidden on the Internet, because the major portions of these networks were funded by the various national governments and research organizations.

In the early 1990s, commercial networks began connecting into these networks, opening it to commercial traffic.

Figure 9-11 Gigapops and high speed backbones of Internet 2/Abilene, vBNS, and CA*Net 3

AbilenevBNSCA*Net 3

Today’s Internet

vBNS Components

The vBNS is accessible to select application sites through four NAPs in New York, San Francisco, Chicago, and Washington, D.C.

The vBNS is mainly composed of OC3 /T3

NAP• Network access point (NAP)

– The NAP is defined as a high-speed network or switch to which a number of routers can be connected for the purpose of traffic exchange. NAPs must operate at speeds of at least 100 Mbps and must be able to be upgraded as required by demand and usage.

– The concept of the NAP is built on the FIX (Federal Internet eXchange) and the CIX (Commercial Internet eXchange), which are built around FDDI rings with attached Internet networks operating at speeds of up to 45 Mbps.

Some vBNS Facts (2001)• Speed: 2.5 Gbps (OC-48)• Multi-protocol Label Switching (MPLS) • 0.001% Packet loss and 100% availability • both unicast and multicast • IPv6 enabled• Extends to Europe and Asia

Abilene• Abilene is an advanced backbone network that

supports the development and deployment of the new applications being developed within the Internet2 community. Abilene connects regional network aggregation points, called gigaPoPs, to support the work of Internet2 universities as they develop advanced Internet applications. Abilene complements other high-performance research networks.

Internet Hosts Growth(Recent statistics)July 1999: 56,218,000 Internet hostsJanuary 2000: 68,862,283 Internet hostsJuly 2000: 86,509,613 Internet hostsJanuary 2001: 113,873,000 Internet hosts (MIDS)Now: ?