1. Chapter Three
Network
Protocols

2. Introduction to Protocols
Rules network uses to transfer data
Protocols that can span more than one LAN segment are routable
SNA & DLC becoming outdated due to non-routability
Multiprotocol network
Network using more than one protocol

3. TCP/IP Transmission Control Protocol/Internet Protocol (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

4. 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

5. 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 (or subnets)

6. 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

7. Internet Protocol (IP)
Version
IPv4 – current version used for 20 years
IPv6 – in process
Time to live (TTL) – max time, in seconds, that a datagram can remain on the network before it is discarded
Also corresponds to # of router hops

8. 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

9. Transport Control Protocol (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

10. Transport Control Protocol (TCP)
Address on host where application makes itself available to incoming data
Figure 3-3: A TCP segment

11. Additional Core Protocols of the TCP/IP Suite
User Datagram Protocol (UDP)
Connectionless transport service
Lack of sophistication makes it more efficient than TCP
Live audio/video transmissions over the Internet
Internet Control Message Protocol (ICMP)
Notifies sender of an error in transmission process and that packets were not delivered
Sits between IP & TCP in Internet layer of TCP/IP model
Used by PING diagnostic tool
Address Resolution Protocol (ARP)
Obtains MAC address of host or node
Creates local database mapping MAC address to host’s IP address

12. TCP/IP Application Layer Protocols
These protocols work over TCP (or UDP) and IP:
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 server to another, using the Internet and other TCP/IP-based networks
Simple Network Management Protocol (SNMP)
Manages devices on a TCP/IP network

13. 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
Example:

14. 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

15. Addressing in TCP/IP Group A Group B Group C
Only 126 available – used/reserved for large corporations or governments
Share the first octet (1-126)
i.e ,
Group B
Share the first two octets ( )
i.e ,
Group C
Share the first three octets ( )
i.e ,

16. Addressing in TCP/IP Loopback address
IP address reserved for communicating from a node to itself
Value of the loopback address is always (try it)
Internet Corporation for Assigned Names and Numbers (ICANN) – formerly InterNIC
Non-profit organization currently designated by U.S. government to maintain and assign IP addresses

17. Addressing in TCP/IP Firewall Host
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
IP address data are sent across the network in binary form
In IP address , 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, , 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. Figure 3-6: IPX/SPX compared to the OSI Model
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
Socket – logical address assigned to a specific process
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
Similar to TCP

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
Can lead to unnecessary network traffic

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 IPX/SPX IPX address
Address assigned to a device on an IPX/SPX network
Contains two parts:
Network address (external network number)
Established Network Admin when network is installed
Node address
NIC MAC address
Example (8.12):
000008A2: E97F3

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
By itself, it is not routable

32. NetBIOS and NetBEUI Compared to the OSI Model
Figure 3-9: NetBIOS/NetBEUI compared to the OSI Model

33. Figure 3-10: Identification tab in Network properties
NetBIOS Addressing
Figure 3-10: Identification tab in Network properties

34. AppleTalk Apple has begun supporting TCP/IP
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
Apple has begun supporting TCP/IP

35. AppleTalk and OSI Model
Figure 3-11: AppleTalk protocol compared to OSI Model

36. 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

37. 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