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Internet Protocols. Chapter III. Contents. TCP/IP and the DoD Model Protocol Header Layers IP Addressing Broadcast Address ICMP ARP IPv6. TCP/IP and the DoD Model. DoD Model Process/Application layer Host-to-Host layer Internet layer Network Access layer. Describe TCP/IP Model.
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Internet Protocols Chapter III
Contents • TCP/IP and the DoD Model • Protocol Header Layers • IP Addressing • Broadcast Address • ICMP • ARP • IPv6
TCP/IP and the DoD Model • DoD Model • Process/Application layer • Host-to-Host layer • Internet layer • Network Access layer
Explain how labels in encapsulation headers are used to manage communication in data networks
Telnet FTP TFTP NFS SMTP LPD X Window SNMP DNS DHCP/BootP The Process/Application Layer Protocols
The Host-to-Host Layer Protocols • Transmission Control Protocol (TCP) • User Datagram Protocol (UDP)
TCP header details (I) • source, destination port:16,16 - identify applications at ends of the connection • sequence:32 - indicates 1st data octet in this segment • acknowledgment:32 - next expected sequence number, valid only when the ACK bit (reside in flag) is set
TCP header details (II) • data offset:4 - 32 bit words offset tells the receiver where user data begins • reserved:6 -not used • flag:6 • URG : validity of urgent pointer field • ACK : validity of acknowledge field • PSH : push request (pass segment to appl layer immediately) • RST : reset the connection • SYN : initial synchronization • FIN : sender at end of byte stream
TCP header details (III) • window:16 - advertise amount of buffer space this node has allocated • checksum:16 - 16 bits 1’s complement of pseudo header, TCP header and data • urgent pointer:16 - byte position of data that should be processed first • options - variable length option e.g. MSS (max segment size) tells destination node
The Internet Layer Protocols • Internet Protocol (IP) • Internet Control Message Protocol (ICMP) • Address Resolution Protocol (ARP) • Reverse Address Resolution Protocol (RARP) • Proxy ARP
Possible Protocols Found in the Protocol Field of an IP Header
Network Addressing • Network Address Range: Class A • 00000000 = 0 • 01111111 = 127 • Network Address Range: Class B • 10000000 = 128 • 10111111 = 191 • Network Address Range: Class C • 11000000 = 192 • 11011111 = 223
Broadcast Addresses • Layer 2 broadcasts These are sent to all nodes on a LAN. • Broadcasts (layer 3) These are sent to all nodes on the network. • Unicast These are sent to a single destination host. • Multicast These are packets sent from a single source, and transmitted to many devices on different networks.
Layer 2 broadcasts • known as hardware broadcasts • they only go out on a LAN • The broadcast would be all 1s in binary and all Fs in hexadecimal, as in FF.FF.FF.FF.FF.FF.
Broadcasts (layer 3) • Broadcast messages are meant to reach all hosts on a broadcast domain. • example that you’re already familiar with: The network address of 172.16.0.0 255.255.0.0 would have a broadcast address of 172.16.255.255 • Broadcasts can also be “all networks and all hosts,” as indicated by 255.255.255.255. • A good example of a broadcast message is an Address Resolution Protocol (ARP) request.