Lecture 7© 1999, Cisco Systems, Inc.   www.cisco.com
   Handles high-level protocols, issues of    representation, encoding, and dialog control.   The TCP/IP protocol suite ...
Five basic services:   Segmenting upper-layer application    data   Establishing end-to-end operations   Sending segmen...
   The purpose of the Internet layer is to    send packets from a network node and    have them arrive at the destination...
   The network access layer is    concerned with all of the issues that    an IP packet requires to actually    make a ph...
• An IP address is a 32-bit sequence of 1s and 0s.• To make the IP address easier to use, the address is  usually written ...
Class A, B, C, D, and E IP       Addresses
IPv4 Addressing
Reserved IP Addresses• Certain host addresses are  reserved and cannot be  assigned to devices on a  network.• An IP addre...
Public and Private IP Addresses• No two machines that connect to a public network can have  the same IP address because pu...
• In TCP/IP communications, a datagram on a local-area  network must contain both a destination MAC address and  a destina...
• Each device on a network maintains  its own ARP table.• A device that requires an IP and  MAC address pair broadcasts an...
   The Transmission Control Protocol (TCP) is one of    the core protocols of the Internet Protocol Suite. TCP    is so c...
   A TCP segment consists of two sections:   header ( port no. , sequence no.)   data
TCP connections have three phases: connection establishment data transfer connection termination
   To establish a connection, TCP uses a three-way    handshake
   Client sending a SYN to the server.   In response, the server replies with a SYN-    ACK.   Finally the client sends...
   Ordered data transfer - the destination host rearranges    according to sequence number   Retransmission of lost pack...
The port numbers are divided into three ranges: The Well Known Ports are those in the range 0–1023. On Unix-   like opera...
The port numbers are divided into three ranges: The Well Known Ports are those in the range 0–1023. On Unix-   like opera...
   The Netstat (Network Statistics) is command-line tool that    displays network connections (incoming and outgoing)   ...
   The TCPView is graphical version of Netstat that will    show you detailed listings of all TCP and UDP endpoints    on...
Лекц 7
Лекц 7
Лекц 7
Лекц 7
Лекц 7
Лекц 7
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Лекц 7

  1. 1. Lecture 7© 1999, Cisco Systems, Inc. www.cisco.com
  2. 2.  Handles high-level protocols, issues of representation, encoding, and dialog control. The TCP/IP protocol suite combines all application related issues into one layer and ensures this data is properly packaged before passing it on to the next layer.
  3. 3. Five basic services: Segmenting upper-layer application data Establishing end-to-end operations Sending segments from one end host to another end host Ensuring data reliability Providing flow control
  4. 4.  The purpose of the Internet layer is to send packets from a network node and have them arrive at the destination node independent of the path taken.
  5. 5.  The network access layer is concerned with all of the issues that an IP packet requires to actually make a physical link to the network media. It includes the LAN and WAN technology details, and all the details contained in the OSI physical and data link layers.
  6. 6. • An IP address is a 32-bit sequence of 1s and 0s.• To make the IP address easier to use, the address is usually written as four decimal numbers separated by periods.• This way of writing the address is called the dotted decimal format.
  7. 7. Class A, B, C, D, and E IP Addresses
  8. 8. IPv4 Addressing
  9. 9. Reserved IP Addresses• Certain host addresses are reserved and cannot be assigned to devices on a network.• An IP address that has binary 0s in all host bit positions is reserved for the network address.• An IP address that has binary 1s in all host bit positions is reserved for the network address.
  10. 10. Public and Private IP Addresses• No two machines that connect to a public network can have the same IP address because public IP addresses are global and standardized.• However, private networks that are not connected to the Internet may use any host addresses, as long as each host within the private network is unique.• RFC 1918 sets aside three blocks of IP addresses for private, internal use.• Connecting a network using private addresses to the Internet requires translation of the private addresses to public addresses using Network Address Translation (NAT).
  11. 11. • In TCP/IP communications, a datagram on a local-area network must contain both a destination MAC address and a destination IP address.• There needs to be a way to automatically map IP to MAC addresses.• The TCP/IP suite has a protocol, called Address Resolution Protocol (ARP), which can automatically obtain MAC addresses for local transmission.
  12. 12. • Each device on a network maintains its own ARP table.• A device that requires an IP and MAC address pair broadcasts an ARP request.• If one of the local devices matches the IP address of the request, it sends back an ARP reply that contains its IP-MAC pair.
  13. 13.  The Transmission Control Protocol (TCP) is one of the core protocols of the Internet Protocol Suite. TCP is so central that the entire suite is often referred to as "TCP/IP." Whereas IP handles lower-level transmissions from computer to computer as a message makes its way across the Internet, TCP operates at a higher level, concerned only with the two end systems.
  14. 14.  A TCP segment consists of two sections: header ( port no. , sequence no.) data
  15. 15. TCP connections have three phases: connection establishment data transfer connection termination
  16. 16.  To establish a connection, TCP uses a three-way handshake
  17. 17.  Client sending a SYN to the server. In response, the server replies with a SYN- ACK. Finally the client sends an ACK back to the server.
  18. 18.  Ordered data transfer - the destination host rearranges according to sequence number Retransmission of lost packets - any cumulative stream not acknowledged will be retransmitted[1] Discarding duplicate packets Error-free data transfer Flow control Congestion control - sliding window
  19. 19. The port numbers are divided into three ranges: The Well Known Ports are those in the range 0–1023. On Unix- like operating systems, binding a communications socket to a port in this range requires administrative privileges or possessing CAP_NET_BIND_SERVICE capability. The Registered Ports are those in the range 1024–49151. The Dynamic and/or Private Ports are those in the range 49152– 65535. Randomly chosen port numbers out of this range are called ephemeral ports. These ports are not permanently assigned to any publicly defined application
  20. 20. The port numbers are divided into three ranges: The Well Known Ports are those in the range 0–1023. On Unix- like operating systems, binding a communications socket to a port in this range requires administrative privileges or possessing CAP_NET_BIND_SERVICE capability. The Registered Ports are those in the range 1024–49151. The Dynamic and/or Private Ports are those in the range 49152– 65535. Randomly chosen port numbers out of this range are called ephemeral ports. These ports are not permanently assigned to any publicly defined application
  21. 21.  The Netstat (Network Statistics) is command-line tool that displays network connections (incoming and outgoing) It is used for finding problems in network and to determine the amount of traffic on network as a performance measurement Netstat provides :Protocol information ,Local address ,Foreign address ,State of TCP Connections In command prompt use command netstat ? To check out all options available
  22. 22.  The TCPView is graphical version of Netstat that will show you detailed listings of all TCP and UDP endpoints on your systems TCPView provides a more informative and conveniently presented subset of the Netstat program

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