Chapter 2 Internet Protocol Objectives Understand the DOD TCP IP reference model Identify the TCP IP protocols Explain the format and content of the TCP IP headers Describe the different classes of IP addresses Understand the need for and process of Network Address Translation The DoD and OSI Models Interchanging names between DOD and OSI The TCP IP Protocol Suite Process Application Layer Protocols Purpose Provides user interface Node to node application communication Process Application Layer Protocols Telnet File Transfer Protocol FTP Trivial File Transfer Protocol TFTP Network Line File System NFS Printer Daemon LPD Process Application Layer Protocols X Window Simple Network Management Protocol SNMP Domain Name Service DNS Dynamic Host Configuration Protocol DHCP Hypertext Transmission Protocol HTTP The TCP IP Protocol Suite Host to Host Layer Protocols Purpose Shield upper layer application from network complexities Sets up transmission services Protocols Transmission Control Protocol TCP User Datagram Protocol UDP TCP Positive Acknowledgment with retransmission Reliable Connection oriented Break streams of data into segments Sequence numbers each segment Arrive in order and a reassembled 3 way handshake occurs here TCP Segment Format TCP Segement UDP Economy thin protocol Connectionless Unreliable Segments blocks of data Application may take the responsibility Sequence numbers the segment But does no checking Used with protocols like SNMP Low overhead UDP Segment UDP Segment Key Concepts TCP Sequenced Reliable Connection oriented Virtual circuit UDP Unsequenced Unreliable Connectionless Low overhead Port Numbers Purpose Used to communicate with upper layers Port Numbers 1024 Well known port numbers Defined in RFC 1700 linked to specific applications or protocols Destination Port 1024 Dynamically assigned Used by upper layers to communicate between hosts Source Port Some Well Know Port Numbers 20 tcp File Transfer Default Data 21 tcp File Transfer Control 23 tcp Telnet 24 tcp any private mail system 24 udp any private mail system 25 tcp Simple Mail Transfer 27 tcp NSW User System FE 27 udp NSW User System FE 29 tcp MSG ICP 29 udp MSG ICP 31 tcp MSG Authentication http www stengel net tcpports htm Port Numbers for TCP UDP Host Sending HTTP Request Server Sending HTTP Reply The TCP IP Protocol Suite Internet Layer Protocols Routing and single interface to upper layers Internet Protocol IP All other protocols exist to support Network addressing Internet Control Message Protocol ICMP Address Resolution Protocol ARP Reverse Address Resolution Protocol RARP IP Header IP Packet The Protocol Field in an IP Header IP Header Protocols 1 Broadcast Domain 5 Collision Domains 1 B Domain 1 C Domain 1 B Domain 1 C Domain ICMP Works at the Network Layer Management and messaging protocol for IP ICMP Router Discovery Extension of ICMP Allows Hosts to discover routes to gateways Router advertisements Router solicitations ICMP con t Destination Buffer Unreachable Full Hops Ping Trace Route IP Header Local APR Broadcast ARP Broadcast RARP Broadcast IP Addressing What is it Numeric Identifier assigned to each host Terminology Bit one digit 1 or 0 Byte 7 or 8 digits Octet Always 8 bits base 8 addressing Network Address Used to send packets to a remote network Broadcast Address Sends information to all nodes on a network All networks 255 255 255 255 All nodes 172 16 255 255 All subnets hosts 10 255 255 255 Understanding Binary Binary Hexidecimal Hierarchical IP Addressing Scheme Flat IP addressing scheme 4 billion address addresses 32 bits Divided into 4 sections or octets or bytes Each byte containing 8 bits Depicting Dotted IP addresses decimal 172 16 30 56 Binary 10101100 00010000 00011110 00111000 Hexadecimal AC 10 1E 38 Network Addressing Network Address Range Class A 7 bits used Network Address Range Class B 14 bits used 128 191 16 384 Network Address Range Class C 21 bits used 1 126 All 0 s can t used 127 reserved 192 223 2 097 152 Network Address Ranges Classes D E Summary of the Three Classes of Networks Special Purpose Addresses Network address all 0 s This network All 1 s All Networks 127 0 0 1 Local Host Node address all 0 s Network Address Node address all 1 s All Nodes this network Entire IP address all 0 s Reserved Entire IP address all 1 s All nodes Current Network Broadcast Addresses Layer 2 Broadcasts All nodes on the LAN Broadcasts Layer 3 All nodes on a network Unicast Sent to a single host Multicast Sent to a group of hosts Class A Addresses Structure Network node node node Network 126 Networks Class A Valid Host IDs 10 0 0 0 All host bits off 10 255 255 255 All host bits on Valid hosts 10 0 0 1 10 255 255 254 0 s 255s are valid hosts but hosts bits cannot all be off or on at the same time 224 2 16 777 214 Nodes Class B Addresses Structure Network Network Network node node Network 214 16 384 Networks Class B Valid Host IDs 172 16 0 0 All host bits off 172 16 255 255 All host bits on Valid hosts 172 16 0 1 172 16 255 254 0 s 255s are valid hosts but hosts bits cannot all be off or on at the same time 216 2 65 534 Nodes Class C Addresses Structure Network Network Network Network Network node Network 221 2 097 152 Class C Valid Host IDs 192 168 100 0 All host bits off 192 168 100 255 All host bits on Valid hosts 192 168 100 1 192 168 100 254 0 s 255s are valid hosts but hosts bits cannot all be off or on at the same time 28 2 254 Nodes Private IP Addresses Not Externally Routable 10 0 0 0 10 255 255 255 172 16 0 0 172 31 255 255 192 168 0 0 192 168 255 255 Network Address Translation NAT Static Dynamic 1 1 Mapping Private IP Address to Global IP Address Requires a large number of Global Addresses No Mapping Addresses assigned much like DHCP Overloading All Private Addresses use same Global Address Use Port Address Translation Things to Know Process Application layer protocols Host To Host Protocols Internet Layer protocols Classes of address and their ranges Broadcast Multicast addressing Binary Hexadecimal conversion