1. TCP/IP Past, Present, and Future
Chapter 6

2. Learning Objectives Describe the history of TCP/IP
Explain how TCP and IP work and how UDP is employed instead of TCP
Describe IP addressing and understand how to use it on LANs and WANs
Explain new IP version 6 and its intended use
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3. Learning Objectives
Discuss how to use application protocols in the TCP/IP suite
Understand TCP/IP application protocols
Compare TCP/IP to OSI reference model

4. A Brief History of TCP/IP
First attempt to make ARPANET available for universal access (1960s)
Network Control Protocol (NCP)
Improvements on reliable communication (1970s)
Transmission Control Protocol (TCP)
Initially designed for point-to-point communications between computers on same network
Internet Protocol (IP)
Initially developed to enable communications between computers linked to different networks or to WANs

5. TCP/IP Language computers use to “talk” over Internet
Protocol of choice for most medium- and large-sized networks
Good choice for most LAN-to-WAN installations
Broad acceptance
Reliable history
Extensive capabilities

6. Understanding TCP/IP
Layered set of protocols similar to, but not identical to, OSI protocol layers
Consists of nearly 100 nonproprietary protocols that interconnect computer systems efficiently and reliably
Core components
Transmission Control Protocol (TCP)
User Datagram Protocol (UDP)
Internet Protocol (IP)

7. How TCP Works
Establishes communication sessions between networked software application processes
Provides reliable end-to-end delivery of data by controlling data flow
Sequencing and acknowledging frames

8. TCP Frame

9. TCP Source and Destination Ports

10. TCP Ports

11. How UDP Works
Connectionless alternative to TCP that yields a lower overhead, but is less reliable
Relies only on checksum to ensure reliability
Handles and transmits data faster; performs no flow control, sequencing, or acknowledgment

12. UDP Frame

13. How IP Works
Enables packets to reach a destination on a local or remote network by using dotted decimal addressing
Used in combination with TCP or UDP

14. Transport Options Compatible with TCP/IP
Ethernet
Token ring
X.25
FDDI
ISDN
DSL
Frame relay
ATM (with conversion)

15. Basic Functions of IP Data transfer Packet addressing Packet routing
Fragmentation
Simple detection of packet errors

16. IP as a Connectionless Protocol
Provides network-to-network addressing and routing information
Changes size of packets when size varies between networks

17. TCP/IP Packet Encapsulation

18. IP Packet

19. How IP Addressing Works
Identifies specific node and network on which it resides
Each IP address is unique
Dotted decimal notation format
32-bits long; four fields
Five classes (Class A through Class E)
Reflect size of network and whether packet is unicast or multicast

20. Role of the Subnet Mask Designated portion of IP address used to:
Indicate class of addressing used on a network
Divide network into subnetworks to control network traffic

21. Creating Subnetworks
Using a subnet mask to divide a network into smaller networks:
Enables Layer 3 devices to ignore traditional address class designations
Creates more options for segmenting networks through multiple subnets and additional network addresses
Classless Interdomain Routing (CIDR) addressing
Newer way to ignore address class designation
Provides more IP address options for medium-sized networks

22. How IPv6 Works
Provides logical growth path from IPv4 so that applications and network devices can handle new demands
Replaces class-based addresses
Designed to be CIDR-compliant
Offers options to create distinctions within a single address

23. Features of IPv6 128-bit address capability
Single address associated with multiple interfaces
Address autoconfiguration and CIDR addressing
40-byte header instead of IPv4’s 20-byte header
New IP extension headers can be implemented for special needs, including more routing and security options

24. IPv6 Autoconfiguration Techniques
Stateful autoconfiguration
Employs server management software and leases to automatically assign IP addresses based on parameters set by network administrator
Based on Dynamic Host Configuration Protocol (DHCP)
Stateless autoconfiguration
Network device assigns its own IP address without obtaining it from a server

25. Types of IPv6 Packets
Unicast
Anycast
Multicast

26. Fields of the IPv6 Header

27. IPv6 Extension Headers Hop-by-hop Routing Fragment Authentication
Encapsulating security payload
Destination options

28. Example of Extension Headers in an IPv6 Packet

29. Determining Packet Size
Using information acquired from maximum transmission unit (MTU) path discovery, the sending node fragments packets and includes fragment extension header
Authentication extension header ensures that the datagram is received s it was sent

30. Encryption and the IP Packet
Using encapsulating security payload extension header
Supports key encryption techniques compatible with Data Encryption Standard (DES) security

31. TCP/IP Application Protocols
Telnet
File Transfer Protocol (FTP), Trivial File Transfer Protocol (TFTP), and Network File System (NFS)
Simple Mail Transfer Protocol (SMTP)
Domain Name System (DNS)
Dynamic Host Configuration Protocol (DHCP)
Address Resolution Protocol (ARP)

32. Telnet Provides terminal emulation
Comes with nearly all vendor implementations of TCP/IP
Open standard
Supported by wide range of workstations

33. Telnet Encapsulated in TCP

34. Telnet Communications Options
7- or 8-bit compatibility
Use of different terminal nodes
Character echoing at sending and receiving ends
Synchronized communications
Transmission of character streams or single characters
Flow control

35. FTP Transfers files in bulk data streams
Uses two TCP ports (20 and 21)
Commonly used on the Internet

36. Sample FTP Commands

37. TFTP
Designed for transfer of files that enable a diskless workstation to boot
Connectionless; runs within UDP
Intended for transfer of small files when data transmission errors are not critical and there is no need for security

38. NFS
Transfers information in record streams instead of in bulk file streams
Connection-oriented
Suited to computers that perform high-volume transaction processing involving records stored within data file of databases

39. SMTP
Designed for exchange of electronic mail between networked systems
No login ID/password required for remote system
Can send only text files
Two parts to messages
Address header
Message text

40. SMTP

41. DNS
Converts a computer or domain name to an IP address or converts an IP address to a computer or domain name (resolution)
Two parts of computer name, divided
Name of computer or node
Name of organization (root domain name)

42. Internet Top Level Domain Conventions

43. Country Names for Domains

44. Examples of Proposed TLDs

45. DNS DNS resolvers and namespaces Use of zones Forward lookup zone
Host address (A) resource record
Reverse lookup zone
Pointer (PTR) resource record

46. DNS DNS server roles DNS standards Primary DNS server
Secondary DNS server
Makes sure there is a copy of primary DNS server’s data
Enables DNS load balancing
Can be spread to different parts of a network
DNS standards
Service resource record
DNS dynamic update protocol

47. DHCP
Automatically leases IP addresses to computers on a network

48. ARP
Enables computer/device to determine MAC address of another computer/device
Reverse Address Resolution Protocol (RARP)
Used by a network node to determine its own IP address

49. SNMP Gathers network performance information for troubleshooting
Developed in 1980s to provide alternative to OSI standard for network management, Common Management Interface Protocol (CMIP)

50. Advantages of SNMP Operates independently on the network
Does not depend on two-way connection at protocol level with other network entities
Can analyze network activity
Management functions are carried out at a network management station
Lower memory overhead than CMIP

51. SNMP Node types used with SNMP Management Information Base (MIB)
Network management station (NMS)
Network agents
Management Information Base (MIB)
Database of network performance information stored on a network agent for access by a network management station

52. MIB Variables

53. Improvements in SNMP v2 Encrypted community name
Improved error handling
Multiprotocol support
Support for IPX and AppleTalk
Fast data transmission and ability to retrieve more MIB-II information at one time

54. Monitoring with SNMP and SNMPv2
Network Associates’ Sniffer software
Microsoft’s Network Monitor
Remote Network Monitoring (RMON)

55. Other TCP/IP Application Protocols
Archie
Bootstrap Protocol (BOOTP)
Distance Vector Multicast Routing Protocol (DVMRP)
Finger
Gopher
Hypertext Transfer Protocol (HTTP)
Internet Group Management Protocol (IGMP)
Multicast Open Shortest Path First Protocol (MOSPF)
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56. Other TCP/IP Application Protocols
Open Shortest Path First (OSPF)
Ping
Real-Time Protocol (RTP)
Real-Time Transport Control Protocol (RTCP)
Resource Reservation Protocol (RSVP)
Routing Information Protocol (RIP)
Simple Network Management Protocol (SNMP)
Traceroute (tracert)

57. TCP/IP and OSI Reference Model Compared

58. Chapter Summary TCP/IP details UDP as alternative to TCP
Internals of the TCP and IP packets
IP addressing
UDP as alternative to TCP
When communications acknowledgement is not as important as speed and low overhead
IPv6 compared to IPv4
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59. Chapter Summary Application protocols associated with TCP/IP for:
Terminal emulation
File transfers
Address naming conversions
IP address assignment
Network management
How TCP/IP relates to OSI reference model