Networking Fundamentals Network Protocols

Protocol Rule for how networks communicate Each OSI layer handled by one or more protocols Protocol Suites Most common: TCP/IP TCP/IP IPX/SPX IPX/SPX NetBIOS NetBIOS AppleTalk AppleTalk

Transmission Control Protocol / Internet Protocol Suite of subprotocols Internet’s standard protocol suite Most common protocol in LANs Four layers in the suite Application Application Transport Transport Internet Internet Network Interface Network Interface

OSI Model – TCP/IP OSI Model TCP/IP Model Application Application Presentation Session TransportTransport NetworkInternet Data Link Network Interface Physical

TCP/IP Protocols Application Layer TFTP, FTP, SMTP, HTTP, DHCP TFTP, FTP, SMTP, HTTP, DHCP Transport Layer TCP, UDP TCP, UDP Internet Layer IP IP Network Layer

Internet Layer Protocol (IP) Defines how and where data should be sent Allows internetworking Routing across multiple LANs Routing across multiple LANs Creates IP Datagrams Packets that enclose data in routing information Packets that enclose data in routing information

Transport Layer Protocols TCP Provides reliable data delivery Provides reliable data delivery Provides error checking and sequencing Provides error checking and sequencing Wraps data with sequencing information Wraps data with sequencing information

Other TCP/IP Protocols User Datagram Protocol (Transport) Used to speed up audio/video transfer Used to speed up audio/video transfer Less error checking (overhead) Less error checking (overhead) Internet Control Message Protocol Reports which networks are unreachable Reports which networks are unreachable Address Resolution Protocol (Internet) Keeps a small table of IP-MAC translations Keeps a small table of IP-MAC translations Reduces network traffic Reduces network traffic

Application Layer Protocols HTTP Receive and display web pages Receive and display web pagesSMTP Send and receive Send and receive No management No managementFTP Send and receive files Send and receive filesTelnet Manages connection to control another device Manages connection to control another deviceSNMP Collect usage statistics and send to central location Collect usage statistics and send to central location

TCP/IP Addressing Logical address vs. MAC address TCP/IP uses 4 octets (8-bit bytes) Assigned by ICANN and administrators Organization: Class A: Class A: Class B: Class B: Class C: Class C: Subnets and Subnet Masks Reserved IP addresses

IPv6 (IPng) Use 128 bits for an address instead of octets 16 octets 3,911,873,538,269,506,102 addresses per square meter of entire planet (almost 4 quintillion addresses, conservatively) According to Wikipedia enough addresses for each atom in each person alive today Max payload size increases from 1500 bytes (v4) to 9000 bytes (v6)

IPv6 New address structure AA:BB:CC:DD:EE:FF:AA:BB:CC:DD:EE:FF:AA:BB:CC:DD

IPv6 Planned overlap and transition from IPv4 US Gov’t backbones must be IPv6 compliant by 2008 Estimated required by See Wikipedia for more details en.wikipedia.org/wiki/Ipv6

TCP/IP Addressing Firewalls allow administrators to assign their own IP addresses When accessing Internet, these networks must assign valid IP address to device When accessing Internet, these networks must assign valid IP address to device NAT NAT Has reduced need for IPv6 Dynamic Host Configuration Protocol (DHCP) Assign IPs dynamically instead of statically Assign IPs dynamically instead of statically