`
`topology and media unimportant
`unimportant
`
`For us: topology and media
`For us:
`
`pair, radio, satellite
`pair, radio, satellite
`many different media: fiber optic, coaxial cable, twisted
`many different media: fiber optic, coaxial cable, twisted
`(WAN)
`(WAN)
`local area networks (LAN) versus wide-area networks
`local area networks (LAN) versus wide-area networks
`
`many ``topologies'' possible:
`many ``topologies'' possible:
`communication links
`communication links
`a set of computers and/or switches connected by
`a set of computers and/or switches connected by
`
`What is a Computer Network?
`What is a Computer Network?
`
`••
`
`••
`
`••
`
`••
`
` Ross, Kurose -
`Ross, Kurose - Chapter 1
`Chapter 1
`Tannenbaum - - 1.1-1.5, 1.7-1.9
`1.1-1.5, 1.7-1.9
`
`Reading:
`Reading: Tannenbaum
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`internetworking
`internetworking
`history
`history
`examples
`examples
`architecture
`architecture
`layered network
`layered network
`architecture
`architecture
`elements of network
`elements of network
`network?
`network?
`
`••
`
`••
`
`••
`
`••
`
`••
`
`Introduction: what is a
`Introduction:
` what is a
`
`Introduction to Networking
`Introduction to Networking
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
`
`Page 1 of 14
`
`LENOVO ET AL. EXHIBIT 1024
`Lenovo et al. v. Intellectual Ventures I, LLC
`IPR2017-00477
`
`
`
`2
`
`on demand resource use: statistical resource sharing
`on demand resource use: statistical resource sharing
`(e.g., link bandwidth, buffers) with other packets
`(e.g., link bandwidth, buffers) with other packets
`packets traversing network share network resources
`packets traversing network share network resources
`"packets''
`"packets''
`data entering network divided into chunks called
`data entering network divided into chunks called
`
`uu
`
`••
`
`••
`
`Packet-Switching
`Packet-Switching
`
`daily by billions of operators, in every nation, ...."
`daily by billions of operators, in every nation, ...."
`cyberspace: "a consensual [environment] experienced
`cyberspace:
` "a consensual [environment] experienced
`an information highway, national information infrastructure
`an information highway, national information infrastructure
`an electronic village
`an electronic village
`are implemented
`are implemented
`a medium through which distributed services/applications
`a medium through which distributed services/applications
`communicate (e.g., email, teleconferencing)
`communicate (e.g., email, teleconferencing)
`a a medium
`resources (e.g., computers, files, data)
`resources (e.g., computers, files, data)
`original justification: allows shared access to computing
`original justification:
` allows shared access to computing
`
`medium through which geographically dispersed users
`through which geographically dispersed users
`
`••
`
`••
`
`••
`
`••
`
`••
`
`••
`
`a software/hardware infrastructure:
`a software/hardware infrastructure:
`
`What is a Computer Network?
`What is a Computer Network?
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
`
`2/14
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`Page 2 of 14
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`
`
`3
`
`delay, loss
`delay, loss
`resource contention:
`resource contention: queuing (waiting),
`queuing (waiting),
`for C for C
`e.g., A and B packets arrive at R1, destined
`e.g., A and B packets arrive at R1, destined
`available:
`available:
`resources demands may exceed resources
`resources demands may exceed resources
`
`••
`
`••
`
`••
`
`example: telephone network
`example: telephone network
`
`uu
`
`duration
`duration
`needed by call dedicated to that call for
`needed by call dedicated to that call for
`all resources (e.g. communication links)
`all resources (e.g. communication links)
`
`••
`
`Circuit Switched Networks
`Circuit Switched Networks
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
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`3/14
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`Page 3 of 14
`
`
`
`4
`
`Baran, 1965)
`, 1965)
`bursty'' (on/off), then packet-
` (on/off), then packet-
`
`switching is advantageous (
`switching is advantageous (Baran
`if users are ``
`if users are ``bursty''
`probability of` "contention.''
`probability of` "contention.''
`can support many more callers, with small
`can support many more callers, with small
`active is less than 0.0004!
`active is less than 0.0004!
`probability that 10 or more callers simultaneously
`probability that 10 or more callers simultaneously
`packet-switching: with 35 ongoing calls,
`packet-switching:
` with 35 ongoing calls,
`capacity. Can support 10 callers.
`capacity. Can support 10 callers.
`circuit-switching: give each caller 100
`circuit-switching:
`send only 10% of time.
`send only 10% of time.
`Kbits Kbits/sec when transmitting; each user has data to
`/sec when transmitting; each user has data to
`example: 1
`example: 1 Mbit
`save/make money!
`save/make money!
`
` Kbits/sec
`/sec
`
` give each caller 100 Kbits
`
` Mbit/sec link; each user requires 100
`/sec link; each user requires 100
`
`••
`
`••
`
`••
`
`••
`
`••
`
`••
`
`K.Ross on circuit switching vs vs packet switching
`packet switching
`
`Hotlink K.Ross on circuit switching
`
`advantages: ??
`advantages: ??Hotlink
`drawbacks: ??
`drawbacks: ??
`resource contention: blocking
`resource contention:
`A and B want to call C
`A and B want to call C
`available
`available
`resource demands may exceed resources
`resource demands may exceed resources
`
`blocking (busy signal)
`(busy signal)
`
`••
`
`••
`
`••
`
`••
`
`••
`
`Why statistically share resources?
`Why statistically share resources?
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
`
`4/14
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`Page 4 of 14
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`
`
`5
`
`protocols in every day life:
`protocols in every day life:
`service, or to get something done
`service, or to get something done
`rules by which two or more people communicate to provide a
`rules by which two or more people communicate to provide a
`actions taken on receipt of message
`actions taken on receipt of message
`format/order of messages exchanged
`format/order of messages exchanged
`
`••
`
`••
`
`••
`
`protocols define :
`protocols define :
`(applications, hosts, routers) communicate with each other
`(applications, hosts, routers) communicate with each other
`protocol: rules by which active network elements
`protocol:
` rules by which active network elements
`
`Protocols
`Protocols
`
`••
`
`••
`
`••
`
`internet: collection of interconnected networks
`internet:
`collection of interconnected networks
`single
`single administrative domain
` administrative domain
`network: set of node (hosts/routers/gateways) within
`network:
` set of node (hosts/routers/gateways) within
`gateway: router directly connected to 2+ networks (e.g. A)
`gateway:
` router directly connected to 2+ networks (e.g. A)
`routing packets from input line to output line. (e.g., A->C)
`routing packets from input line to output line. (e.g., A->C)
`router: computer (often w/o applications-level programs)
`router:
` computer (often w/o applications-level programs)
` applications which use network (e.g.: H1
` applications which use network (e.g.: H1
`host: computer running
`host:
` computer running
`
`broadcast (e.g.,: Ethernet LAN)
`broadcast (e.g.,: Ethernet LAN)
`point-point (e.g., A-to-B)
`point-point (e.g., A-to-B)
`communication links:
`communication links:
`
`••
`
`••
`
`Elements of a Network
`Elements of a Network
`
`••
`
`••
`
`••
`
`••
`
`••
`
`••
`
`
`
`
`
`
`
`
`1/16/2018
`
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`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
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`5/14
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`Page 5 of 14
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`
`
`6
`
`view view
`a a distributed
`components
`components
`hardware/software
`hardware/software
`geographically distributed
`geographically distributed
`the network consists of
`the network consists of
`
`distributed layered
`layered
`
`••
`
`••
`
`requested
`requested
`interfaces define how services
`interfaces define how services
`
`layers
`layers
`layer N change doesn't affect other
`layer N change doesn't affect other
`information/complexity hiding
`information/complexity hiding
`
`••
`
`••
`
`of how that service implemented
`of how that service implemented
`service from lower layer independent
`service from lower layer independent
`to provide a service to layer N+1
`to provide a service to layer N+1
`layer N relies on services of layer N-1
`layer N relies on services of layer N-1
`simplified by layering.
`simplified by layering.
`complex system architecture
`complex system architecture
`
`••
`
`••
`
`••
`
`••
`
`Layered network architecture
`Layered network architecture
`
`Layered Architecture
`Layered Architecture
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
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`6/14
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`Page 6 of 14
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`
`
`7
`
`Hotlink: an IETF view of standards
`
`The Internet and ISO/OSI
`The Internet and ISO/OSI
`
`reference models
`reference models
`
`logical versus physical communication:
`logical versus physical communication:
`communication service provided by layer N-1.
`communication service provided by layer N-1.
`"packets") with each other, using
`"packets") with each other, using
`provide service by communicating (sending
`provide service by communicating (sending
`peer entities (e.g., processes) in layer N
`peer entities (e.g., processes) in layer N
`
`••
`
`••
`
`Layering and protocols
`Layering and protocols
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
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`7/14
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`Page 7 of 14
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`
`
`8
`
`Internet: TCP and UDP
`matching
`
`•
`
`•sender/receiver speed
`
`from higher layers
`
`•may multiplex several streams
`
`delivery of data
`transport service: end-to-end
`
`•
`
`transport layer
`•a "thin" layer
`
`•
`
`(broken session)
`
`•session set up (e.g., authentication), recovery from failure
`
`•session layer (OSI only)
`
`cont
`cont))
`Layers of a protocol architecture
`Layers of a protocol
` architecture
`
`((
`
` endian versus
` versus
`
`endian byte orders, integer and floating point numbers).
` byte orders, integer and floating point numbers).
`
`Internet stack: data conversion a user-level concern
`Internet stack: data conversion a user-level concern
`big- big-endian
`conversion of data to a common format (e.g., little
`conversion of data to a common format (e.g., little endian
`
`••
`
`••
`
`presentation layer (OSI only)
`presentation layer (OSI only)
`
`buffering and delivery of data at end systems
`buffering and delivery of data at end systems
`
`••
`
`socket layer (Internet only)
`socket layer (Internet only)
`
`••
`
`••
`
`Retrieval
`Retrieval
`teleconferencing, info.
`teleconferencing, info.
`examples: WWW, email,
`examples: WWW, email,
`communication
`communication
`process-to-process
`process-to-process
`
`••
`
`••
`
`application layer
`application layer
`
`••
`
`Layers of a protocol architecture
`Layers of a protocol architecture
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
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`
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`9
`
`transmitting raw bits (0/1) over wire
`transmitting raw bits (0/1) over wire
`
`••
`
`physical layer
`physical layer: stuff of EE's
`: stuff of EE's
`
`••
`
`Ethernet, HDLC, PPP
`Ethernet, HDLC, PPP
`sender/receiver
`sender/receiver
`speed matching between
`speed matching between
`multiaccess
`multiaccess LAN protocols
` LAN protocols
` single link
` single link
`communication over a
`communication over a
`point-to-point error free
`point-to-point error free
`
`
`
`
`
`
`••
`
`••
`
`••
`
`••
`
`data link layer
`data link layer
`
`••
`
`Layers of a protocol architecture
`Layers of a protocol architecture
`
`cont
`cont))
`
`((
`
`Internet: IP packets, BGP, RIP
`Internet: IP packets, BGP, RIP
`bottleneck avoidance, congestion control
`bottleneck avoidance, congestion control
`at routers: control packet routing
`at routers: control packet routing
`at end hosts: start packets on their way
`at end hosts: start packets on their way
`
`••
`
`••
`
`••
`
`••
`
`network layer
`network layer
`
`••
`
`Layers of a protocol architecture
`Layers of a protocol architecture
`
`cont
`cont))
`
`((
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
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`
`
`10
`
`encapsulated in packet at
` in packet at
`
`“envelope within envelope””
`“envelope within envelope
`lower layer
`lower layer
`data at one layer encapsulated
`data at one layer
`protocol entities in a given layer
`protocol entities in a given layer
`packet
`packet: unit of data exchanged between
`: unit of data exchanged between
`
`••
`
`••
`
`••
`
`Protocol packets
`Protocol packets
`
`HotLink: info on new (post 1995) Internet structure in US
`
`Internet protocols
`Internet protocols
`runs same software: the
`runs same software: the
`the the Internet: each network
` Internet: each network
`administered separately
`administered separately
`each network
`each network
`
`a network of networks
`a network of networks
`
`••
`
`networks
`networks
`interconnection of many
`interconnection of many
`an internet:
`an internet:
`
`••
`
`••
`
`••
`
`Internetworks
`Internetworks: the Internet
`: the Internet
`
`1/16/2018
`
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`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
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`
`
`11
`
`•layer N may need layer N-2 information (e.g.,
`
`lower layer packet sizes)
`
`•different layers may need same info (e.g.,
`
`e.g., error recovery hop-hop versus end-end
`
`•layer N may duplicate lower level functionality,
`
`timestamp)
`
`•layering has conceptual, structuring advantages
`
`but …
`
`Layering Considered Harmful or
`Layering Considered Harmful or
`
`Difficult
`Difficult
`
`identifiers associated with entities
`
`•addressing/naming: locating, managing
`•connection setup: handshaking with peer
`
`share single lower level connection
`
`•multiplexing: several higher level sessions
`
`into smaller pieces; reassembly
`
`•fragmentation: dividing large data chunks
`•flow control: avoid flooding slower peer
`•error control: make “channel” more reliable
`
`Generic issues in a layer
`Generic issues in a layer
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
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`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
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`
`
`12
`
`•Arpanet has 100 nodes
`•companies: DECnet, IBM SNA
`
`1970’s:
`
`•Arpanet has 4 nodes
`
`1960’s: packet switching (Baran, Davies)
`1876: telephone (circuit-switching)
`1830: telegraph
`
`A Brief History of Networking
`A Brief History of Networking
`
`network of workstations with high-speed interconnect
`
`•network/multiprocessor distinction can be blurred:
`
`link length limited to several meters
`communication
`“finer-grained” communication than network
`
`•
`
`•
`
`•processors connected by high-speed interconnect
`Multiprocessors
`
`implement higher-level services
`relies on network communication service to
`file system, atomic remote actions
`
`•
`
`•application-level concerns and semantics: distributed
`Distributed system
`
`Network, distributed system, parallel
`Network, distributed system, parallel
`
`processor?
`processor?
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
`
`12/14
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`Page 12 of 14
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`
`
`13
`
`Hotlink: Hobbe’s Internet Timeline
`Hotlink: Vinton Cerf on Internet History
`
`•security
`•commercialization
`•continued expansion
`
`Current trends:
`
`•WWW drives Internet mania
`•wireless networks
`•150Mbps, 660 Mbps
`•explosive growth: 10 million hosts in 1996
`
`•Arpanet, NSFnet retired: gov’t no longer provides
`
`backbone service
`
`1990’s:
`
`A Brief History of Networking
`A Brief History of Networking
`
`Internet passes 100,000 nodes in 1989
`MILNET, NSFNET, ARPANET
`
`•
`
`•proliferation of wide area networks: CSNET,
`
`late 80’s: 100 Mbps
`local area networks
`
`•
`
`•
`
`1980’s:
`
`A Brief History of Networking
`A Brief History of Networking
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
`
`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
`
`13/14
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`Page 13 of 14
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`
`
`14
`
`layering
`layering
`the pieces of a network architecture
`the pieces of a network architecture
`packet-switching versus circuit-switching
`packet-switching versus circuit-switching
`
`••
`
`••
`
`••
`
`Summary
`Summary
`
`1/16/2018
`
`CMPSCI 653: Introduction to Networking
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`http://lass.cs.umass.edu/~shenoy/courses/spring00/653/lectures/Intro.pdf
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`14/14
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`