Chapter Three

1
Chapter Three

• Network
• Protocols

2
Objectives

• Identify characteristics of TCP/IP, IPX/SPX,
  NetBIOS, and AppleTalk
• Understand position of network protocols in OSI
  Model
• Identify core protocols of each protocol suite
  and its functions
• Understand each protocols addressing scheme
• Install protocols on Windows 98 and Windows 2000
  clients

3
Introduction to Protocols

• Protocol
• Rules network uses to transfer data
• Protocols that can span more than one LAN segment
  are routable
• Multiprotocol network
• Network using more than one protocol

4
TCP/IP
OSI Model
TCP/IP

• Transmission Control Protocol/Internet Protocol
  (TCP/IP)
• Suite of small, specialized protocols called
  subprotocols

Figure 3-1 TCP/IP compared to the OSI Model
5
TCP/IP Compared to theOSI Model

• Application layer roughly corresponds to Session,
  Application, and Presentation layers of OSI Model
• Transport layer roughly corresponds to Transport
  layers of OSI Model
• Internet layer is equivalent to Network layer of
  OSI Model
• Network Interface layer roughly corresponds to
  Data Link and Physical layers of OSI Model

6
The TCP/IP Core Protocols

• Certain subprotocols of TCP/IP suite
• Operate in Transport or Network layers of OSI
  Model
• Provide basic services to protocols in other
  layers of TCP/IP
• TCP and IP are most significant core protocols in
  TCP/IP suite

7
Internet Protocol (IP)

• Provides information about how and where data
  should be delivered
• Subprotocol that enables TCP/IP to internetwork
• To internetwork is to traverse more than one LAN
  segment and more than one type of network through
  a router
• In an internetwork, the individual networks that
  are joined together are called subnetworks

8
Internet Protocol (IP)

• IP datagram
• IP portion of TCP/IP frame that acts as an
  envelope for data
• Contains information necessary for routers to
  transfer data between subnets

Figure 3-2 Components of an IP datagram
9
Internet Protocol (IP)

• IP is an unreliable, connectionless protocol,
  which means it does not guarantee delivery of
  data
• Connectionless
• Allows protocol to service a request without
  requesting verified session and without
  guaranteeing delivery of data

10
Transport Control Protocol (TCP)

• TCP
• Provides reliable data delivery services
• Connection-oriented subprotocol
• Requires establishment of connection between
  communicating nodes before protocol will transmit
  data
• TCP segment
• Holds TCP data fields
• Becomes encapsulated by IP datagram

11
Transport Control Protocol (TCP)

• Port
• Address on host where application makes itself
  available to incoming data

Figure 3-3 A TCP segment
12
Additional Core Protocols of the TCP/IP Suite

• User Datagram Protocol (UDP)
• Connectionless transport service
• Internet Control Message Protocol (ICMP)
• Notifies sender of an error in transmission
  process and that packets were not delivered
• Address Resolution Protocol (ARP)
• Obtains MAC address of host or node
• Creates local database mapping MAC address to
  hosts IP address

13
TCP/IP Application Layer Protocols

• Telnet
• Used to log on to remote hosts using TCP/IP
  protocol suite
• File Transfer Protocol (FTP)
• Used to send and receive files via TCP/IP
• Simple Mail Transfer Protocol (SMTP)
• Responsible for moving messages from one e-mail
  server to another, using the Internet and other
  TCP/IP-based networks
• Simple Network Management Protocol (SNMP)
• Manages devices on a TCP/IP network

14
Addressing in TCP/IP

• IP Address
• Logical address used in TCP/IP networking
• Unique 32-bit number
• Divided into four groups of octets (8-bit bytes)
  that are separated by periods
• IP addresses are assigned and used according to
  very specific parameters

15
Addressing in TCP/IP
Table 3-1 Commonly used TCP/IP classes

• Though 8 bits have 256 possible combinations,
  only the numbers 1 through 254 are used to
  identify networks and hosts
• Numbers 0 and 255 are reserved for broadcasts
• Broadcast are transmissions to all stations on a
  network

16
Addressing in TCP/IP

• Loopback address
• IP address reserved for communicating from a node
  to itself
• Value of the loopback address is always 127.0.0.1
• Internet Corporation for Assigned Names and
  Numbers (ICANN)
• Non-profit organization currently designated by
  U.S. government to maintain and assign IP
  addresses

17
Addressing in TCP/IP

• Firewall
• Specialized device (typically a router)
• Selectively filters or blocks traffic between
  networks
• May be strictly hardware-based or may involve a
  combination of hardware and software
• Host
• Computer connected to a network using the TCP/IP
  protocol

18
Addressing in TCP/IP

• In IP address 131.127.3.22, to convert the first
  octet (131) to a binary number
• On Windows 2000, click Start, point to Programs,
  point to Accessories, then click Calculator
• Click View, then click Scientific (make sure Dec
  option button is selected)
• Type 131, then click Bin option button
• The binary equivalent of number 131, 10000011,
  appears in the display window

19
Addressing in TCP/IP

• Static IP address
• IP address manually assigned to a device
• Dynamic Host Configuration Protocol (DHCP)
• Application layer protocol
• Manages dynamic distribution of IP addresses on a
  network

20
Viewing Current IP Information
Figure 3-4 Example of an IP configuration window
21
Viewing Current IP Information
Figure 3-5 IP address information on a Windows
2000 workstation
22
Addresses and Names

• In addition to using IP addresses, TCP/IP
  networks use names for networks and hosts
• Each host requires a host name
• Each network requires a network name, also called
  a domain name
• Together, host name and domain name constitute
  the fully qualified domain name (FQDN)

23
IPX/SPX

• Internetwork Packet Exchange/Sequenced Packet
  Exchange (IPX/SPX)
• Protocol originally developed by Xerox
• Modified and adopted by Novell in the 1980s for
  the NetWare network operating system

Figure 3-6 IPX/SPX compared to the OSI Model
24
IPX/SPX Core Protocols

• Internetwork Packet Exchange (IPX)
• Operates at Network layer of OSI Model
• Provides routing and internetworking services
• Similar to IP in TCP/IP suite

Figure 3-7 Components of an IPX datagram
25
IPX/SPX Core Protocols

• Sequenced Packet Exchange (SPX)
• Belongs to Transport layer of OSI Model
• Works in tandem with IPX to ensure data are
  received
• Whole
• In sequence
• Error free

26
IPX/SPX Core Protocols
Figure 3-8 SPX packet encapsulated by an IPX
datagram
27
IPX/SPX Core Protocols

• Service Advertising Protocol (SAP)
• Works in Application, Presentation, Session, and
  Transport layers of OSI Model
• Runs directly over IPX
• Used by NetWare servers and routers to advertise
  to entire network which services they can provide

28
IPX/SPX Core Protocols

• NetWare Core Protocol (NCP)
• Works within Presentation and Sessions layers of
  OSI Model
• Works over IPX
• Handles requests for services between clients and
  servers

29
Addressing in SPX/IPX

• IPX address
• Address assigned to a device on an IPX/SPX
  network
• Contains two parts
• Network address (external network number)
• Node address

30
NetBIOS and NetBEUI

• Network Basic Input Output System (NetBIOS)
• Originally designed by IBM to provide Transport
  and Session layer services
• Adopted by Microsoft as its foundation protocol
• Microsoft added Application layer component
  called NetBEUI

31
NetBIOS and NetBEUI

• NetBIOS Enhanced User Interface
• Fast and efficient protocol
• Consumes few network resources
• Provides excellent error correction
• Requires little configuration
• Can handle only 254 connections
• Does not allow for good security

32
NetBIOS and NetBEUI Compared to the OSI Model
Figure 3-9 NetBIOS/NetBEUI compared to the OSI
Model
33
NetBIOS Addressing
Figure 3-10 Identification tab in Network
properties
34
AppleTalk

• Protocol suite used to interconnect Macintosh
  computers
• Originally designed to support peer-to-peer
  networking among Macintoshes
• Can now be routed between network segments and
  integrated with NetWare- and Microsoft-based
  networks
• AppleTalk networks are separated into logical
  groups of computers called AppleTalk zones

35
AppleTalk and OSI Model
Figure 3-11 AppleTalk protocol compared to OSI
Model
36
AppleTalk Subprotocols

• AppleShare
• AppleTalk Filing Protocol (AFP)
• AppleTalk Session Protocol (ASP)
• AppleTalk Transaction Protocol (ATP)

37
AppleTalk Subprotocols

• Name Binding Protocol (NBP)
• Routing Table Maintenance Protocol (RTMP)
• Zone Information Protocol (ZIP)
• Datagram Delivery Protocol (DDP)

38
Addressing in AppleTalk

• AppleTalk node ID
• Unique 8-bit or 16-bit number identifying a
  computer on an AppleTalk network
• AppleTalk network number
• Unique 16-bit number identifying the network to
  which a node is connected

39
Installing Protocols

• After installing protocols, they must be binded
  to NICs and services they run on or with
• Binding
• Process of assigning one network component to
  work with another

40
Chapter Summary

• Protocols define standards for communication
  between nodes on a network
• Protocols vary in speed, transmission efficiency,
  utilization of resources, ease of setup,
  compatibility, and ability to travel between one
  LAN segments
• TCP/IP is becoming most popular network protocol

41
Chapter Summary

• TCP/IP suite of protocols can be divided into
  four layers roughly corresponding to seven layers
  of OSI Model
• Operating in Transport or Network layers of OSI
  Model, TCP/IP core protocols provide
  communications between hosts on a network
• Each IP address is a unique 32-bit number,
  divided into four groups of octets separated by
  periods

42
Chapter Summary

• Every host on a network must have a unique number
• Internetworking Packet Exchange/Sequenced Packet
  Exchange (IPX/SPX) is a protocol originally
  developed by Xerox then modified and adopted by
  Novell in the 1980s for its NetWare network
  operating system
• Core protocols of IPX/SPX provide services at
  Transport and Network layers of OSI Model

43
Chapter Summary

• Addresses on an IPX/SPX network are called IPX
  addresses
• Network Basic Input Output System (NetBIOS) was
  originally developed by IBM to provide Transport
  and Session layer services
• Microsoft adopted NetBIOS as its foundation
  protocol, then added an Application layer
  component called NetBIOS Enhanced User Interface
  (NetBEUI)

44
Chapter Summary

• To transmit data between network nodes, NetBIOS
  needs to know how to reach each workstation
• Each workstation must have a NetBIOS name
• AppleTalk is the the protocol suite used to
  interconnect Macintosh computers
• An AppleTalk network is separated into logical
  groups of computers called AppleTalk zones

45
Chapter Summary

• Though Apple has improved AppleTalks ability to
  use different network models and span network
  segments, it remains unsuited to large LANs or
  WANs
• In addition to zone names, AppleTalk uses node
  IDs and network numbers to identify computers on
  a network
• Though some protocols (such as NetBIOS) require
  no configuration after installation, others (such
  as TCP/IP) do require configuration