Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
An introduction to the internet, focusing on its layered structure, protocols, and historical development. It covers the concept of layering in networks, the functions of each layer, and the importance of proper layering. The document also discusses the internet protocol stack, including application, transport, network, link, and physical layers. Additionally, it explains the role of each layer in logical and physical communication, as well as the process of data transfer between layers.
Typology: Slides
1 / 15
This page cannot be seen from the preview
Don't miss anything!
1: Introduction 1
1: Introduction 2
ftp, smtp, http
tcp, udp
ip, routing protocols
ppp, ethernet
1: Introduction 4
Layering: logical communication
application transport network link physical
application transport network link physical application transport network link physical
application transport network link physical
network link physical
data
data
take data from app
add addressing, reliability check info to form “datagram”
send datagram to peer
wait for peer to ack receipt
analogy: post office
data
transport
transport
ack
1: Introduction 5
Layering: physical communication
application transport network link physical
application transport network link physical application transport network link physical
application transport network link physical
network link physical
data
data
1: Introduction 7
Internet structure: network of networks
e.g. BBN/GTE, Sprint, AT&T, IBM, UUNet interconnect (peer) with each other privately, or at public Network Access Point (NAPs)
connect into NBPs
connect into regional ISPs
regional ISP
regional ISP
local ISP
local ISP
1: Introduction 8
1: Introduction 10
Internet History
1970: ALOHAnet satellite network in Hawaii
1973: Metcalfe’s PhD thesis proposes Ethernet
1974: Cerf and Kahn - architecture for interconnecting networks
late70’s: proprietary architectures: DECnet, SNA, XNA
late 70’s: switching fixed length packets (ATM precursor)
1979: ARPAnet has 200 nodes
Cerf and Kahn’s internetworking principles: minimalism, autonomy - no internal changes required to interconnect networks best effort service model stateless routers decentralized control define today’s Internet architecture
1972-1980: Internetworking, new and proprietary nets
1: Introduction 11
Internet History
1980-1990: new protocols, a proliferation of networks
1: Introduction 13
ATM: Asynchronous Transfer Mode nets
today’s de facto
ATM Forum ITU
small (48 byte payload, 5 byte header) fixed length
fast switching small size good for voice virtual-circuit network: switches maintain state for each “call” well-defined interface between “network” and “user” (think of telephone company)
1: Introduction 14
ATM layers
ATM Adaptation Layer (AAL): interface to upper layers end-system segmentation/rea ssembly
ATM Layer: cell switching
Physical
AAL ATM physical
AAL ATM physical
AAL ATM physical
AAL ATM physical
ATM physical
Where’s the application? ATM: lower layer functionality only IP-over ATM: later
application TCP/UDP IP
application TCP/UDP IP application TCP/UDP IP
application TCP/UDP IP
