1 / 50

Chapter 6

Chapter 6. Networking Protocols. Introduction. Topics Protocol Basics Protocol Characteristics Transmission Control Protocol/Internet Protocol Network Access Layer Protocols Internet Layer Protocols Transport Layer Protocols Application Layer Protocols. Protocol Basics.

LionelDale
Download Presentation

Chapter 6

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 6 Networking Protocols

  2. Introduction • Topics • Protocol Basics • Protocol Characteristics • Transmission Control Protocol/Internet Protocol • Network Access Layer Protocols • Internet Layer Protocols • Transport Layer Protocols • Application Layer Protocols

  3. Protocol Basics • A protocol is a set of rules that determines how computers exchange information over a network medium • A wide variety of communication protocols exist, and many of them rely on others for operation • Groups of related protocols are often called stacksorprotocol stacks

  4. Protocol Characteristics • Data packets can be sent over a medium using any one of a number of protocols • Protocols can be either standard or proprietary • Standard protocols • Support universal communication so equipment from different manufacturers can interact

  5. Proprietary Protocols • Proprietary protocols are vendor specific and are usually protected by patents or other legal stipulations • Proprietary protocols include • XNS • NetBIOS • IPX/SPX • AppleTalk • DECNet

  6. Xerox Network System (XNS) • XNS is a suite of protocols created by Xerox in the late 1970s for Ethernet networks • XNS is rarely used in new networks today

  7. NetBios • The Network Basic Input/Output System (NetBIOS) interface was developed in 1983 for IBM • The intention was to allow applications on different computers to communicate within a local area network • NetBIOS was not designed for large networks

  8. IPX/SPX • Novell introduced Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) in the early 80s • This stack was based on the XNS network protocol family • IPX is the Network layer protocol • SPX is the Transport layer protocol

  9. AppleTalk • AppleTalk is Macintosh’s networking protocol • It is designed to be a flexible, simple, and inexpensive network means for connecting computers, peripherals, and servers • Newer versions of Macintosh operating systems use TCP/IP and SMB as default protocols rather than AppleTalk • AppleTalk is a protocol and LocalTalk is a media type

  10. DECnet • DECnetis a proprietary network protocol designed by Digital Equipment Corporation • Currently two versions of DECnet are in use: • DECnet Phase IV which is based on the Phase IV Digital Network Architecture (DNA) • DECnet/OSI also called DECnet Phase V is a layered model

  11. Transmission Control Protocol/Internet Protocol • TCP/IP is considered the language of the Internet • It is the most widely used protocol today • It is a suite, or stack, of small, specialized protocols • Because of its routing ability, TCP/IP has become the standard for many LANs, as well as for the Internet

  12. Transmission Control Protocol/Internet Protocol • In the early 1970s, the Department of Defense funded ARPA to design a new set of computer communication protocols that would allow multiple networks to be interconnected in a flexible and dynamic way • The protocol developed was originally called Network Control Protocol • This success led to the implementation of the two main Internet protocols • These are Transmission Control Protocol and Internet Protocol (TCP/IP)

  13. Transmission Control Protocol/Internet Protocol • The TCP/IP suite maps the seven layers of the OSI model to a four-layer model • The TCP/IP model focuses more on interconnectivity than on functional layers

  14. Internet and OSI Model

  15. Transmission Control Protocol/Internet Protocol • The TCP/IP model is also called the Internet reference model • Layers • Network Access • Internet • Transport • Application

  16. The TCP/IP Protocol Suite

  17. Network Access Layer Protocols • The Network Access layer is the lowest layer in the model • It Maps to Layers 1 (Physical) and 2 (Data Link) of the OSI model • It is responsible for the framing (DL) and physical delivery of datagrams

  18. Network Access Layer Protocols • Access Layer Protocols deliver data to computers and devices on the network • These include Serial Line Interface Protocol (SLIP) and Point-to-Point Protocol (PPP) • These protocols support serial data transmission over a modem

  19. Network Access Layer Protocols • Other Network Access protocols • the Address Resolution Protocol (ARP) • the Reverse Address Resolution Protocol (RARP) • Provide a means of mapping IP addresses to MAC addresses • These protocols provide a means for last hop message delivery

  20. Local ARP Broadcast

  21. RARP Broadcast Example

  22. Internet Layer Protocols • The layer above the Network Access layer is called the Internet layer • It manages the routing of packets that are to be forwarded on to different networks • It relies on routable protocols for delivery

  23. Internet Layer Protocols • The Internet Protocol (IP) is responsible addressing and routing of data packets • Routing tables created by routing protocols are used to forward messages from one network to another • It is a low overhead, best effort delivery protocol

  24. The Internet Layer Protocols • IP • ICMP • ARP • RARP

  25. IP Message Format • IP Packets or datagrams consist of a header, data (payload), and a trailer • The header contains routing information • Trailers contain a checksum value, which is used to determine if data was corrupted during transmission

  26. IP Header

  27. Packet Delivery • IP compares the destination address in the packet header to router table addresses • If the address corresponds to a local network, the datagram is delivered to the appropriate computer • If the address corresponds to a remote network, the packet is passed to a router for delivery

  28. Routing Controls • Time to Live (TTL) • prevents packets from circulating on the network forever • The TTL value is decremented by one each time the packet traverses a router (each hop) • Default value is usually 120 • Fragmentation – Routers may break oversize packets into fragments, then route the individual fragments, which are reassembled at the destination computer

  29. Fragmentation • Each subnetwork has a maximum transmission unit (MTU), which is the largest packet it can transfer • A datagram received from one network may be too large to be transmitted as a single packet on another network • Fragmentation is the process of dividing a packet into smaller pieces

  30. Internet Control Message Protocol • ICMP • Internet layer protocol • uses IP to send its messages • uses IP as if it was higher-level protocol • used as an aid for other protocols • used to test for connectivity and search for configuration errors in a network

  31. ICMP Error Messages • Destination Unreachable – message returned to sender if a router cannot forward an IP datagram • Buffer Full – message returned until congestion due to full buffer has abated • Hops – an IP datagram has passed through its allotted number of routers • Ping – ICMP echo messages are returned to sender if destination exists and is reachable • Traceroute – ICMP timeouts used to discover path a packet takes as it traverses an internetwork

  32. PING • Used to test connectivity • uses the ICMP echo function • A small packet containing an ICMPecho message is sent through the network to a particular IP address • The computer that sent the packet then waits for a return packet • If the connections are good and the target computer is up, an echo message is returned to the sender

  33. Traceroute • Originally developed for the Unix operating system • used to track the path a packet takes from sender to destination • Calculates travel time for each hop • uses an ICMP echo request packet to determine the path

  34. Transport Layer Protocols • The protocol layer above the Internet layer • provides a reliable communication service so that extended two-way conversations may take place • responsible for providing end-to-end data integrity

  35. Key Features of TCP and UDP

  36. Transport Layer Protocols • Transmits data as a stream of characters • initiates and terminates the connections between sender and receiver • Two main protocols • Transmission Control Protocol (TCP) • User Datagram Protocol (UDP)

  37. Protocols That Use TCP and UDP

  38. Transmission Control Protocol (TCP) • provides connection-oriented data transmission • supports multiple data streams • provides for flow and error control • uses sequence numbers and acknowledgements to guarantee delivery

  39. TCP Connections • TCP communications are port to port • A socket is an IP address plus a port number • Well-defined port numbers have been assigned to common applications

  40. Port Numbers • Used to communicate with upper layers by keeping track of conversations with different services (applications) • Well-Known port numbers define different application locations on the server that hosts the applications

  41. Well-Known Port Numbers

  42. TCP Segment Format

  43. User Datagram Protocol (UDP) • a connectionless protocol • Low overhead - does not provide either sequencing or acknowledgements • used a lot in telephony traffic and the Remote Procedure Call (RPC) • UDP does not provide the reliability that TCP provides

  44. UDP Segment Format

  45. Application Layer Protocols • The top layer in the Internet reference model • Provides applications access to network services

  46. ApplicationLayer Protocols • Telnet – remote client access to resources on a Telnet server • FTP – reliable file transport using TCP; requires authentication • TFTP – Unreliable file transport using UDP • NFS – allows file sharing on different platforms • SMTP – delivers mail to a server; use POP or IMAP to retrieve mail • LPD – for printer sharing • X Window – graphical interface for client/server applications • SNMP –Provides network management by polling capable devices • DNS –maps host names to IP addresses • DHCP – provides IP address configuration to workstations

  47. File Transfer and Remote Access • File Transfer Protocol (FTP) which allows files to be uploaded and downloaded on port 21 • Telnet which uses terminal emulation for access to remote hosts using port 23 • Both FTP and Telnet use TCP as their Transport layer protocol

  48. Mail and Internet • Simple Mail Transfer Protocol (SMTP) which supports basic message delivery services to mail servers on port 25 • HyperText Transfer Protocol (HTTP) which is a low-overhead Web browser service protocol that uses port 80

  49. Management and News • Simple Network Management Protocol (SNMP) which uses UDP port 161 to collect information from network devices. • Network News Transfer Protocol (NNTP): handles distribution and posting of news articles using port 119

  50. Address Assignment and Name Mapping • Dynamic Host Configuration Protocol (DHCP) allows for automatic IP addressing • Domain Name Service (DNS) uses UDP port 53 for resolving domain names to IP addresses

More Related