Network Protocols

1. Network Protocols Chapter 8

2. Chapter Objectives • List the different types of network protocols • Identify the working of each network protocol • Explain the functions of different protocols in TCP/IP protocol suite • Configure IPX/SPX on Windows XP • Install NetBIOS/NetBEUI on Windows XP Jetking Infotrain Ltd.

3. Recall • MAC address is a hardware address that is permanently embedded into NIC • When two nodes are connected by directly connecting cables, it is called direct cable connection • Two types of volt-ohm meters: • Analog • Digital • Function of a probe is to trace signal emitted by the tone generator Jetking Infotrain Ltd.

4. Introducing Protocols • Set of predefined rules used by devices in network for data transfer • Network Protocols: • NetBIOS/NetBEUI • TCP/IP • ARP/RARP • ICMP/IGMP • UDP • IPX/SPX • HDLC/SDLC Jetking Infotrain Ltd.

5. NetBIOS/NetBEUI • Developed by IBM and later adopted by Microsoft • Network Basic Input/Output System (NetBIOS) used for communication within LAN • Operates at Transport and Session layers of OSI model • NetBIOS Extended User Interface (NetBEUI) adds capabilities to NetBIOS and an advanced version of NetBIOS used in MS Windows OS • Widely used in Ethernet, Token Ring and Windows NT networks Jetking Infotrain Ltd.

6. NetBIOS Services • Supports three distinct services: Name service for name registration and resolution, Session service for connection oriented communication and datagram service for connectionless communication Jetking Infotrain Ltd.

7. Name Service • Implemented in Microsoft Windows as Windows Internet Name Service (WINS). • Provides means to application to register its NetBIOS name • NetBIOS names are 16 bytes length • Service uses UDP port 137 • Name Service functions include • Add Name • Add Group Name • Delete Name • Find Name Jetking Infotrain Ltd.

8. Session Service Establishes session for data exchange between computers using TCP port 139 Session Termination Process Session Establishment Process Jetking Infotrain Ltd.

9. Datagram Service • Uses the UDP port 138 and provides a connectionless and broadcast-oriented data communication between two devices. • Divides data in datagrams before sending • Datagram service functions include: • Send Datagram • Send Broadcast Datagram • Receive Datagram • Receive Broadcast Datagram Jetking Infotrain Ltd.

10. NetBIOS Name Resolution • Used to map NetBIOS names to IP addresses • Methods used to resolve names: • NetBIOS Name Cache • NetBIOS Name Server (NBNS) • Local Broadcast Jetking Infotrain Ltd.

11. NetBEUI • Enhanced version of NetBIOS • Used by LAN manager, LAN server, Windows for workgroups, Windows 95 and Windows NT • Adapted to other protocols such as IPX or TCP/IP as it does not support routing of messages to other networks Jetking Infotrain Ltd.

12. TCP/IP • Two layer communication protocol used by Internet • TCP provides connection-oriented reliable transport service • Divides the message into smaller packets called segments • IP is a connectionless and unreliable datagram protocol and provides no error checking • IP transfers data in the form of packets called datagrams Jetking Infotrain Ltd.

13. TCP/IP Protocol Suite • Designed before OSI model • Consists of five layers • Provides independent protocols at each layer Jetking Infotrain Ltd.

14. Description of each layer - I • Physical and Data link layer – standard and proprietary protocols are supported by these layers. • Network layer – 1. IP – • 2. ARP – • 3. RARP – • 4. ICMP – used to send query and error reporting messages to the sender and not to correct them • 5. IGMP – Uses class D IP address Jetking Infotrain Ltd.

15. Description of each layer - II • Transport layer – 1. UDP – • 2. TCP – divides data into segments each having a sequence number • 3. Stream Control Transmission Protocol (SCTP) – multiple streams of data can be transmitted simultaneously. Used over wireless network and transmission of multimedia data. Supports voice over IP and combines the best features of TCP and UDP Jetking Infotrain Ltd.

16. Description of each layer - III • Application layer – 1. SMTP – • 2. FTP – • 3. DNS – • 4. SNMP – Based on client-server model • NFS – Allows different Operating systems to share files and disk storage • TFTP – Uses UDP to upload or download files and does not provide security features Jetking Infotrain Ltd.

17. TCP Segment Format . Jetking Infotrain Ltd.

18. IPv4 Datagram Format Jetking Infotrain Ltd.

19. IP Datagram Fragmentation • Fragmentation refers to breaking datagrams into pieces • Maximum Transfer Unit (MTU) is maximum amount of data that frame can carry • Datagram is fragmented when its size exceeds MTU of the network • Fragments follow different paths to reach destination Jetking Infotrain Ltd.

20. Explain ARP/RARP from CBT Jetking Infotrain Ltd.

21. ICMP/IGMP • Internet Control Message Protocol (ICMP) provides error reporting and query management mechanism • ICMP handles problems occurring while packet transmission • Internet Group Message Protocol (IGMP) manages multicasting and group membership of devices Jetking Infotrain Ltd.

22. ICMP Message Types ICMP Messages Error Reporting Query Destination Unreachable Echo request and reply Source Quench Timestamp request and reply Time Exceeded Address Mask Request and reply Parameter Problem Router Solicitation and Advertisement Redirection Jetking Infotrain Ltd.

23. Error Reporting Messages • ICMP is used for error reporting not for error correcting 1. Destination Unreachable – 2. Source Quench – used for flow control at network layer 3. Time Exceeded - 4. Parameter Problem – if there is an ambiguity in the header part 5. Redirection – if the host forwards datagram destined for some other network to wrong router Jetking Infotrain Ltd.

24. Query Messages • Echo Request and Reply – Ping command • Timestamp request and reply – • Address Mask request and reply – If a host knows the IP address but does not know the corresponding mask • Router Solicitation and Advertisement – Used to determine whether the routers in the network are working properly Jetking Infotrain Ltd.

25. IGMP Message Types Jetking Infotrain Ltd.

26. UDP • User Datagram Protocol (UDP) provides connectionless process-to-process communication • UDP packets are called user datagrams. • User Datagram Format: Jetking Infotrain Ltd.

27. Explain UDP operation using CBT Jetking Infotrain Ltd.

28. IPX/SPX • Novell NetWare system uses IPX/SPX as communication protocol within networks • IPX operates at Network layer for connectionless communication • SPX operates at Transport layer for connection-oriented communication • Together, IPX/SPX provides same services as TCP/IP Jetking Infotrain Ltd.

29. IPX/SPX Protocol Suite Jetking Infotrain Ltd.

30. IPX/SPX Naming Conventions • IPX/SPX/NetBIOS Compatible Transport Protocol (NWLink) uses two types of IPX network numbers for routing purposes: • Internal network number – Mentioned as Internal network number in NWLink IPX/SPX/NetBIOS Compatible Transport Protocol Properties dialog box It’s a hexadecimal number with 1 to 8 digits (1 to FFFFFFFE) • External network number – Mentioned as Network number in Manual Frame Detection dialog box Jetking Infotrain Ltd.

31. HDLC/SDLC • DLC protocols are two types: asynchronous and synchronous • High Level Data Link Control (HDLC) and Synchronous Data Link Control (SDLC) are bit-oriented synchronous protocols in which data frames are interpreted as series of bits • Both are useful for half-duplex and full-duplex communication • HP adopted DLC protocol for use by network printers • Windows XP still support DLC Jetking Infotrain Ltd.

32. HDLC Nodes and Link Configurations • Types of HDLC nodes are: • Primary Station – transmits frames called commands to secondary stations • Secondary Station – send response frames to primary station • Combined Station • Supported link configurations: • Unbalanced • Balanced Jetking Infotrain Ltd.

33. SDLC • Bit-oriented protocol invented by IBM and similar to HDLC • Only primary and secondary stations are used Jetking Infotrain Ltd.

34. Protocols at Different Layers Jetking Infotrain Ltd.

35. Summary - I • Network protocols are the set of predefined rules, used by the devices connected to network to communicate with each other • Different network protocols include NetBIOS/NetBEUI, TCP/IP and IPX/SPX • NetBIOS protocol is used for communication within a LAN and operates at the session layer of the OSI model • NetBIOS provides three types of services namely Name service, Session service and Datagram service • Name service allows an application to register its NetBIOS name in the network Jetking Infotrain Ltd.

36. Summary - II • Two computers can establish a session for data transfer using the Session service which is a connection-oriented service • In the connectionless Datagram service, data is transferred in the form of small packets called datagrams • NetBIOS name resolution is used to map a NetBIOS names to an IP address. Methods used for resolution are, NetBIOS Name Server (NBNS), NetBIOS name cache and Local Broadcast • LMHOSTS file is a static file that resolves the names to IP address for applications running on the remote computer • TCP/IP is a five-layer protocol suite developed before the OSI model Jetking Infotrain Ltd.

37. Summary - III • TCP is a connection-oriented, reliable and process-to-process transport layer protocol in the TCP/IP protocol suite • At TCP, data is divided into segments with each segment having sequence number for reassembly of the data at the destination • Connection establishment requires three-way handshaking; connection termination requires four-way handshaking process • IP is an unreliable connectionless protocol responsible for source-to-destination delivery • Packets in the IP layer are called datagrams which consist of data and header Jetking Infotrain Ltd.

38. Summary - IV • Fragmentation is the division of a datagram into smaller units when size of the datagram exceeds MTU • ARP protocol is used to obtain the physical address of the device when its logical address is known • RARP protocol is used to obtain the logical address of the device when its physical address is known • ICMP protocol is used to send error and control messages. Two types of ICMP messages are Error-reporting messages and Query messages • Error reporting messages include Destination Unreachable, Source Quench, Time exceeded, Parameter Problem and Redirection Jetking Infotrain Ltd.

39. Summary - V • Query messages include Echo Request and Reply, Timestamp Request and Reply, Address Mask Request and Reply and Router Solicitation and Advertisement • IGMP protocol is used to govern the management of multicast groups in a network. Three types of IGMP messages are Query, Membership Report and Leave Report • UDP protocol operates at the transport layer and provides connectionless and unreliable service • The UDP packet is called as user datagram which is encapsulated into an IP packet • Incoming and outgoing queues hold messages going to and from UDP Jetking Infotrain Ltd.

40. Summary - VI • Novell NetWare operating system uses IPX/SPX protocol for communication within a network • IPX operates at the network layer and provides connectionless routing services using either RIP or NLSP • HDLC is a data link control protocol used for point-to-point communications over a serial links • Three types of devices used in HDLC are primary station, secondary station and combined station • HDLC supports three configuration modes: Normal Response Mode, Asynchronous Response Mode and Asynchronous Balanced Mode Jetking Infotrain Ltd.