Review of Important Networking Concepts. Introductory material. This module uses the example from the previous module to review important networking concepts: protocol architecture, protocol layers, encapsulation, demultiplexing, network abstractions. Networking Concepts.
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Review of Important Networking Concepts
This module uses the example from the previous module to review important networking concepts: protocol architecture, protocol layers, encapsulation, demultiplexing, network abstractions.
DNS: What is the IP address of “neon.tcpip-lab.edu”?
DNS: The IP address of “neon.tcpip-lab.edu” is 220.127.116.11
ARP: What is the MAC address of 18.104.22.168?
ARP: What is the MAC address of 22.214.171.124?
ARP: The MAC address of 126.96.36.199 is 00:20:af:03:98:28
ARP: The MAC address of 188.8.131.52 is 00:e0:f9:23:a8:20
184.108.40.206 is not on my local network.
Therefore, I need to send the packet to my
default gateway with address 220.127.116.11
18.104.22.168 is on my local network.
Therefore, I can send the packet directly.
“what’s the time?”
“I have a question”
… specific msgs sent
… specific actions taken when msgs received, or other events
machines rather than humans
all communication activity in Internet governed by protocols
protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt
a human protocol and a computer network protocol:
Q: Other human protocols?
The TCP/IP protocol suite is the protocol architecture of the Internet
The TCP/IP suite has four layers: Application, Transport, Network, and Data Link Layer
End systems (hosts) implement all four layers. Gateways (Routers) only have the bottom two layers.
The TCP/IP protocol stack does not define the lower layers of a complete protocol stack
1. a peer layer entityusing a common protocol (Peer Protocol)
2. adjacent layersto provide services and to receive services
N+1 Layer Peer Protocol
Communication services are invoked via function calls. The functions are called service primitives
N+1 Layer Peer Protocol
Recall: A layer N+1 entity sees the lower layers only as a service provider
Send IP data-gram to 22.214.171.124
Frame is an IP datagram
Frame is an IP datagram
IP datagram is a TCP segment for port 80
Send HTTP Request to neon
Establish a connection to 126.96.36.199 at port 80
Open TCP connection to 188.8.131.52 port 80
Send IP datagram to 184.108.40.206
Send a datagram (which contains a connection request) to 220.127.116.11
Send the datagram to 18.104.22.168
Send the datagram to 22.214.171.124
Send Ethernet frame to 00:e0:f9:23:a8:20
Send Ethernet frame to 00:20:af:03:98:28
00e0 f923 a820 00a0 2471 e444 0800 4500 002c 9d08 4000 8006 8bff 808f 8990808f 4715 065b 0050 0009 465b 0000 0000 6002 2000 598e 0000 0204 05b4
Option: maximum segment size
The Evolution of Internet
An overview lecture that covers Internet related topics, including a definition of the Internet, an overview of its history and growth, and standardization and naming.
1961: Kleinrock - queueing theory shows effectiveness of packet-switching
1964: Baran - packet-switching in military nets
1967: ARPAnet conceived by Advanced Research Projects Agency
1969: first ARPAnet node operational
ARPAnet demonstrated publicly
NCP (Network Control Protocol) first host-host protocol
first e-mail program
ARPAnet has 15 nodes
1961-1972: Early packet-switching principles
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
define today’s Internet architecture
1972-1980: Internetworking, new and proprietary nets
Early 1990’s: ARPAnet decommissioned
1991: NSF lifts restrictions on commercial use of NSFnet (decommissioned, 1995)
early 1990s: Web
hypertext [Bush 1945, Nelson 1960’s]
HTML, HTTP: Berners-Lee
1994: Mosaic, later Netscape
late 1990’s: commercialization of the Web
Late 1990’s – 2000’s:
more killer apps: instant messaging, P2P file sharing
network security to forefront
est. 50 million host, 100 million+ users
backbone links running at Gbps
1990, 2000’s: commercialization, the Web, new apps
Source: Internet Software Consortium
Sprint US backbone network
Domain names are administered by a large number of private organizations that are accredited by ICANN.