Internet%20Protocols

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Lecture 12

• Internet Protocols
• IPv4 versus IPv6
• UDP
• TCP
• Internet resource allocation and QoS

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Projects and midterm

• Progress report Monday February 25, 8 AM from all
  individuals or groups. Hard Deadline!!
• Midterm Tuesday, February 26, 7-730 PM.
• Material Chapters 1,2, and 4 including todays
  lecture.
• Open book.
• 3 questions 30 minutes

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IPv4
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IPv6
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UDP
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TCP

• Supports
• Error control. For each segment
• Sequence numbers.
• Acknowledgment.
• Timeout
• Example stop and wait protocol. Very
  inefficient.
• Window based
• Flow Control
• Congestion Control

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TCP
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TCP 1 bit flags

• ACK when set the ack value is valid
• SYN, RST, FIN used for connection establishment
  and tear-down
• PUSH data should be passed to the upper layer
  immediately.
• URG there is urgent information in the data

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Data streaming. MSS- maximum segment size
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TCP flow control window
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TCP is a connection-oriented protocol for
client-server communication
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TCP congestion control

• Host centric, feedback-based resource allocation
  policy.
• The congestion control window is affected by the
  timing of the acknowledgments. A late or missing
  acknowledgment signals that the network is
  congested.

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Other Internet protocols

• ICMP used by hosts and routers to exchange
  network layer information, e.g., error reporting
• RIP Routing Information Protocol
• OSPF Open Shortest Path First Protocol

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Internet traffic

• TCP ? 90 95 of the Internet traffic
• 65-75 of TCP traffic is Web related
• 10 of TCP traffic is due to News
• 5 of TCP traffic is due to Email
• 5 of TCP traffic is due to FTP
• 1 of TCP traffic is due to Napster
• UDP ? 5 10 of the Internet traffic
• DNS
• Realaudio
• games

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Flows and resource allocation

• Flow sequence of packets with a common
  characteristics
• A layer-N flow ? the common attribute a layer-N
  attribute
• All packets exchanged between two hosts ? network
  layer flow
• All packets exchanged between two processes ?
  transport layer flow

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