The document discusses several network protocols used at different layers of the OSI model. It introduces NetBIOS/NetBEUI which provides name registration and connection-oriented/connectionless communication over LANs. TCP/IP is described as a layered protocol suite used widely on the internet, with IP, TCP, UDP operating at the network and transport layers. ARP and RARP are discussed as protocols that resolve logical to physical addresses. ICMP and IGMP are control protocols that provide error reporting and multicast group management. IPX/SPX is presented as an alternative to TCP/IP used in Novell networks. HDLC and SDLC are synchronous data link protocols used for communication over WAN links.

1. Network Protocols

2. 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

3. 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

4. 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
NetBIOS
Services
Session Datagram
Name Service
Service Service

5. 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

6. Session Service
Establishes session for data exchange between computers using
TCP port 139
Session Establishment Process Session Termination Process

7. 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

8. 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

9. 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

10. 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

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

12. 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

13. 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

14. 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

15. TCP Segment Format
.

16. IPv4 Datagram Format

17. 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

18. ARP/RARP
• To deliver packet both physical and logical addresses are
necessary
• Address Resolution Protocol (ARP) provides physical
address when logical address is known
• Reverse Address Resolution Protocol (RARP) maps logical
address to physical address
• RARP is useful when device is booted for first time

19. 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

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

21. 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

22. 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

23. IGMP Message Types
IGMP Messages
Membership
Query Leave Report
Report
General Query Special Query

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

25. UDP Operation - I
Encapsulation Decapsulation

26. UDP Operation - II
Client Queue Server Queue

27. 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

28. IPX/SPX Protocol Suite

29. 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

30. 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

31. 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

32. HDLC Data Transfer Modes
• Normal Response Mode (NRM) – Secondary station
requires permission from primary station before sending
data
• Asynchronous Response Mode (ARM) – Secondary
station can transfer without permission from primary
station
• Asynchronous Balanced Mode (ABM) – Either of the
combined station can initiate the transmission

33. SDLC
• Bit-oriented protocol invented by IBM and similar to
HDLC
• Only primary and secondary stations are used
Configurations
Point-to-Point Multipoint Loop Hub go-ahead

34. Protocols at Different Layers
OSI Layers Protocols
Physical Layer No protocols defined
Data Link Layer HDLC, SDLC
Network Layer IP, ICMP, IGMP, ARP, RARP, IPX
Transport Layer NetBEUI, TCP, UDP, SPX
Session Layer NetBIOS, SAP, SMTP, FTP, DNS, SNMP,
Presentation Layer NCP, RIP, NLSP, SMTP, FTP, DNS,
SNMP, NFS
Application Layer SMTP, DNS, SNMP, NFS, TFTP