Protocol Suites Lecture 1
Protocol • An agreed-upon format for transmitting data between two devices.
Communication b/w Nodes • Requires sending and receiving devices • Both devices must be configured for the same protocol or there must be a gateway to translate between the protocols
Network Communication - How • Sending Device (Source) • File/message is separated into smaller parts – segments/packets/frames • Encapsulation - Headers including source and destination addresses – logical and physical – added to front of each part of the message as it moves through the OSI layers; trailers sometimes added – depending on the layer • Encapsulated data is sent through the source NIC via the media to destination NIC.
Network Communication - How • Receiving Device (Destination) • Bits input through destination NIC • Headers and trailers are stripped from the data • Packets are reassembled into file/message (data). • Data is passed to the specific application
Application Application Presentation Presentation Session Session Transport Transport Network Network Data Link Data Link Physical Physical Communication Message to send to Workstation B
Protocol Suite • Groupings of protocols • Examples: • TCP/IP • IPX/SPX • Appletalk
Protocol Categories • Application Protocols • Facilitate client functions • Map to the top three layers of OSI • Transport Protocols • Facilitate communication between nodes • Maps to Layer 4 • Network Protocols • Facilitates addressing for communication between nodes • Maps to Layer 3
Suites • TCP/IP - Transmission Control Protocol/Internet Protocol • Most popular • Available for all platforms and OS • Open source (non-proprietary) • Routable • IPX/SPX – Internetwork Packet Exchange/Sequenced Packet Exchange • Proprietary – Novell • Routable • AppleTalk • Proprietary – Macintosh • Routable • NetBEUI – Net Bios Extended User Interface • Non-routable • Good for a simple LAN or peer to peer network
TCP/IP Protocol Suite • FTP – File Transfer Protocol (AP) • Transferring files (downloading/uploading) • TFTP – Trivial File Transfer Protocol (AP) • Transferring files very quickly (no error checking; uses UDP) • SNMP – Simple Network Management Protocol (AP) • Monitoring network resources • SMTP – Simple Mail Transport Protocol (AP) • Sending mail from a mail server • Telnet – Telecommunication Network (AP) • Processing using a remote server • Terminal emulation • TCP – Transmission Control Protocol (TP) • Connection-oriented • Responsible for reliable end (node) to end (node) connectivity • Provides error detection and handling • UDP – User Datagram Protocol (TP) • Connectionless • Fast • No error checking
TCP/IP Protocol Suite • IP – Internet Protocol (NP) • Connectionless (depends on TCP for reliability) • Logical addressing and best path selection • ARP – Address Resolution Protocol (NP) • Source node knows IP address of destination node; needs MAC address. Sends broadcast on network. Node with matching IP responds with its MAC address. • ICMP – Internet Control Message Protocol (NP) • Provides information regarding errors • PING makes use of ICMP to test connectivity • TRACERT • DNS – Domain Name Service (NP) • Translates named nodes to their IP addresses • Example: Dilleelt is my computer’s name; IP address is 10.19.9.16 • RARP – Reverse Address Resolution Protocol (NP) • Source node knows destination MAC address; needs IP address. Sends request.
Application Presentation Session Transport Network Data Link Physical TCP/IP Suite Mapped to OSI Layers FTP TFTP Telnet SMTP DNS SNMP HTTP TCP UDP
IP Addressing Unique address • IP address for each node must be unique • Four bytes (bytes called octets) • 10.9.19.3 might be a node address • 10.0.0.0 would be the network address • The first 10 in 10.9.19.3 corresponds to the network in this example. • Subnet mask identifies which part of the IP address refers to the network address and which part to the node. • 11111111.00000000.00000000.00000000 (binary subnet mask) • 255.0.0.0 would be the subnet mask
IP Address Classes • Businesses are assigned network IP addresses by IANA – Internet Assigned Numbers Authority - depending on the size of the business. • Class A – very large businesses such as the US government • Class B – large businesses • Class C – medium sized businesses
IP Class Addresses & S/N Masks • The first number of the network address identifies the network class • Class A: 1 – 126 • S/N mask: 255.0.0.0 • Class B: 128 – 191 • S/N mask: 255.255.0.0 • Class C: 192 – 223 • S/N mask: 255.255.255.0