Prof. Alfred J Bird, Ph.D., NBCT Door Code: 52461* Office – McCormick 3rd floor 607 Office Hours – Monday and Thursday 3:00PM to 3:45PM

 Bus  Ring  Star  Mesh

 Four pieces of information are required  Sender name  Sender address  Recipient name  Recipient address

 Two basic classifications  Peer to Peer Networks  Client Server Model  Why do we have networks?  Resource Sharing  Information Sharing

 Broadcast  Multicast  Point to Point  Unicast

 Personal Area Networks  NFC – Near Field Communications  Bluetooth  Local Area Networks (LANs)  Ethernet  WiFi  Metropolitan Area Networks  Wide Area Networks (WANs)  The Internet

 A protocol is a set of rules  Allows intercommunication between machines, processes, layers and services  Many different protocols  HTTP, POP, ICMP, etc.  TCP vs UDP

 OSI  TCP/IP

 Seven Levels  7 – Application  6 – Presentation  5 – Session  4 – Transport  3 – Network  2 – Data Link  1 - Physical

 4 – Applications  3 – Transport  2 – Internet  1 – Network Interface

 Many Organizations  IEEE  W3C  ISO  A myriad of others

 In the USSR during the cold war, all scientists working in defense were located at one location so they could share easily  In the US scientists were spread all over the country so they had trouble sharing.  DOD created ARPA  ARPA contracted with BBN (now a part of Raytheon) to design a network  The network was called ARPAnet

 Tiers of ISPs  Tier 1  ATT  NTT  Verizon (MCI)  Tier 2  Tier 3

.com .net .edu .gov .mil