1. Port Numbers
   1. Used in TCP & UDP
      1. Similar to MAC addresses
   2. Port Numbers 1024 - 65535: assigned by host
   3. Port Numbers 1024 and bellow: Reserved for applications
      1. TCP port numbers
         1. FTP: 21
         2. Telnet: 23
         3. SMTP: 25
         4. DNS: 53
         5. HTTP: 80
         6. HTTPS: 443
      2. UDP Port numbets
         1. DNS: 53
         2. TFTP: 69
         3. SNMP: 161
2. DOD Model
   1. 1: Process/Application Layer
      1. Upper layers of OSI model
      2. Defines protocols for node to node communication
      3. Controls UI specs
   2. 2: Host to Host layer
      1. Transport Layer in OSI model
      2. Defines protocols for setting up the level of transmission service
      3. Creates reliable communication
         1. ensures error free data transfer
      4. handles packet sequencing and data integrity
   3. 3: Internet Layer
      1. Network Layer in OSI model
      2. designates protocols for logical transmission of packets
      3. addresses host with IP address
      4. Handles routing of packets through multiple networks
   4. 4: Access Layer
      1. Data Link and Physical Layer in OSI model
      2. monitors data exchange between hosts
      3. oversees hardware addressing
      4. defines protocols for physical transmission of data
3. IP Addressing
   1. Class A
      1. Address Range: 1-126
      2. Private address range
         1. 10.0.0.0 - 10.255.255.255
      3. Provides 8 network bits and 24 Host bits
   2. Class B
      1. Address Range: 128-191
      2. Private Address Range
         1. 172.16.0.0 - 172.31.255.255
      3. Provides 16 Network bits and 16 Host bits
   3. Class C
      1. Address Range: 192-223
      2. Private address range
         1. 192.168.0.0 - 192.168.255.255
      3. Provides 24 network bits and 8 host bits
   4. Class D
      1. Multicasting
   5. Class E
      1. Research
   6. Reserved IP address
      1. 127.0.0.1
         1. Loop back address
4. Protocols
   1. Process/Application Layer Protocols
      1. TelNet
         1. Allows client to access resources of telnet server
         2. Text based menu
      2. FTP
         1. Transfers files
         2. can be a protocol or program
         3. Reliable
         4. secure
         5. often used with Telnet
      3. TFTP
         1. Stripped down version of FTP
         2. faster
            1. sends smaller blocks
         3. Insecure
      4. LPD
         1. shares printers on a network
      5. SNMP
         1. collects and manipulates variable network info
         2. polls devices on a network
         3. Alerts managers of any problems using a trap
      6. SMTP
         1. Used to send email
         2. spools email to sever once sent
      7. NFS
         1. specialises in file sharing
         2. allows different file systems to interoperate.
      8. XWindows
         1. used for client/server operations using GUI
         2. allows program on one computer to send to another
         3. think Back to my Mac
      9. DNS
         1. Resolves host names
         2. translates URL into IP address
      10. DHCP
          1. Assigns IP addresses to hosts
          2. Host sends out broadcast, DHCP server replies
             1. will tell host many things
             2. IP address
             3. Subnet mask
             4. Domain Name
             5. Default Gateway
             6. DNS
   2. Host to Host layerProtocols
      1. TCP
         1. Segments and sequences data from upper layers
         2. Connection Oriented communication
            1. Virtual circuit
         3. Secure
         4. reliable
            1. Acknowledgements
            2. Flow Control
         5. Full Duplex
         6. Large overhead
      2. UDP
         1. Scaled down 'economy' version of TCP
         2. Less overhead
         3. Unreliable
            1. No acknowledgements
            2. No flow control
         4. Connectionless Oriented Communication
         5. Faster than TCP
         6. No Sequencing used
   3. Internet layer Protocols
      1. IP
         1. Aware of all interconnected networks
         2. Uses Logical addresses
         3. Connectionless Protocol
         4. Routes packets through network
      2. ARP
         1. Resolves IP addresses into MAC addresses
      3. RARP
         1. Resolves MAC addresses to IP addresses
      4. ICMP
         1. Management and messaging protocol
         2. messages carried as datagrams
            1. Provide Hosts with information about network
            2. Network Diagnostics
            3. Destination unreachable message
            4. Encapsulated within IP datagrams
   4. Access layer Protocols
      1. Ethernet
      2. Fast Ethernet
      3. Token Ring
      4. FDDI