Network Protocols and DOS

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Network Protocols and DOS

• CIS 625-1, Spring 2002

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Overview

• TCP/IP Model
• TCP
• IP
• Data Encapsulation
• TCP/IP Suite
• DOS

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TCP/IP Model

• Application
• OSI Application
• OSI Presentation
• OSI Session
• Transport
• OSI Transport
• Internet Protocol
• OSI Network
• Communication Network
• OSI Data Link
• OSI Physical

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TCP

• Reliable host-to-host protocol (RFC 793)
• Operation
• Basic data transfer oversees transfer from app
  to IP
• Reliability requires acknowledgement, error
  checking, sequencing
• Flow control limit amount of data sent
• Multiplexing ports
• Connection maintains connection data
• Precidence and security
• Ports

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IP Addressing

• 32-bit addresses 4 bytes called octets 0..255
• Dot notation 134.114.248.2
• IP addresses divided into classes

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Subnetting and Subnet Masks

• Sub-divide allocated IPs into smaller networks
• Mask
• 1s cover network portion of IP
• 0s reveal nodes designation
• Examples
• Class B to C subnets 255.255.255.0
• Class C subdivided into 14 subnets
  255.255.255.24011111111 11111111 11111111
  11110000

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IP Registration

• Regional Internet Registries (RIRs)
• American Registry for Internet Numbers (ARIN)
• One C Class network is /24
• Smallest block is 32 C Class networks is /19
• 2,500 annual lease fee
• 500 membership fee

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IPv4 and IPv6

• Running out of IP addresses
• Four octet system is IP version 4 (IPv4)
• Proposed system
• IP version 6 (IPv6)
• 128 bit addressing
• Represents IP address in eight 16-bit hex values
  xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

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Data Encapsulation
Presentation
Transport
Network
Data Link
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TCP Segment

• Port Address on host where an application makes
  itself available to incoming data
• Sequence number Order of packets
• Checksum Was the data corrupted

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IP Datagram

• IP portion of a TCP/IP frame that acts as an
  envelope for data
• Contains information necessary for routers to
  transfer data between subnets

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Typical Ethernet Frame

• 802.3 is IEEE standard for Ethernet
• Addresses are MAC addresses
• This is Data Link layer

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TCP/IP Suite

• HTTP
• SMTP
• DHCP
• NNTP
• VoIP
• Telnet
• SNMP

• FTP
• TFTP
• DNS
• TCP
• UDP
• IP

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Other Network Protocols

• Novells IPX/SPX
• IBM/Microsoft
• NetBIOS
• NetBEUI
• Apples AppleTalk

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DOS

• Disk Operating System 10 MB was large
• Borrowed from Unix
• Command line user interface
• Selected commands
• cls
• dir
• type
• copy

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Summary

• Protocol is set of rules
• TCP/IP protocol of Internet communications
• TCP responsible for host-to-host connection
  oriented
• IP transmits device-to-device connectionless
• IP addresses are logical addresses of Internet
• DOS commands still used by NOSs