1. ITEC 370 George Vaughan Franklin University
Protocols
ITEC 370
George Vaughan
Franklin University

2. Sources for Slides
Material in these slides comes primarily from course text, Guide to Networking Essentials,Tomsho, Tittel, Johnson (2007).
Other sources are cited in line and listed in reference section.

3. TCP/IP and OSI Models

4. Function of Protocols Protocol = Rules for communication
Protocols exist for each layer of OSI model.
Some protocols span more than one layer.
Higher layer protocols are more abstract.
When protocols work together to cover multiple OSI layers, they are referred to collectively as a protocol stack (or suite).

5. Connectionless and Connection-Oriented Protocols
No guarantee of delivery
Low overhead, faster
Connections don’t have to be setup or torn down
Rely on upper layers to provide reliable communications
Connection Oriented
Reliable but slower
Receiver sends acknowledgement to indicate successful transfer
Packets are resent in event of error
Upper layers don’t have to worry about reliable transmission

6. Routable and Non-routable Protocols
Operate at Network layer
Support internetworks (MAN, WAN)
Example: TCP/IP
Non-Routable
Does not operate at Network layer
Useful for small LANs
Example: NetBIOS Extended User Interface (NetBEUI)

7. TCP/IP and OSI Models

8. TCP/IP Network Layer Protocols
Internet Protocol version 4 (IPv4 or IP)
Source and Destination logical addressing, routing
Connectionless
Fast but not reliable
Internet Control Message Protocol (ICMP)
Used to send error and control messages
Used by ‘Ping’ utility
Address Resolution Protocol (ARP)
Used to resolve logical (IP) address to physical (MAC) address
Can only be used for two systems in same network.

9. Example of TCP/IP Network Layer Protocols
Computer A needs to send a message to Computer B
Before computer A can send message, it needs the following addresses for computer B:
IP (logical address)
MAC (physical address)
Computer A sends out ARP broadcast message to all devices.
Computer B recognizes IP address in ARP and sends back MAC address to computer A
Computer A now has 2 addresses necessary for send message to computer B.

10. TCP/IP Transport Layer Protocols
Transmission Control Protocol (TCP)
Accepts messages of any length from upper layers
Connection-Oriented
Uses 3-way handshake to establish connection
A sends ‘Synchronize’ (SYN) message to B
B sends ‘Synchronize Acknowledgement’ (SYN-ACK) message back to A
A sends a ‘Forward Acknowledgment’ (ACK) to B
Connection between A and B is now established.
TCP is responsible for fragmenting application into segments
TCP is responsible for reassembling the application data from segments.
TCP uses Acknowledgment messages to:
Ensure that data is properly received.
Manage flow control

11. TCP/IP Transport Layer Protocols (Cont.)
User Datagram Protocol (UDP)
Connectionless
Faster, but less reliable than TCP
UDP itself does not segment application data
UDP does not use acknowledgements
UDP is used by some higher layer protocols such as NFS and DNS.

12. TCP/IP Application Layer Protocols
Domain Name System (DNS)
Name-to-Address resolution system
einstein.franklin.edu  (try ‘nslookup einstein.franklin.edu’
Hypertext Transport Protocol
Web-pages, browsers, servers
File Transfer Protocol (FTP)
Telnet
Simple Mail Transport Protocol (SMTP)

13. TCP/IP Application Layer Protocols Tomsho, Tittel, Johnson (2007)
DHCP
Detailed configuration of devices, keeping track of assigned addresses and to which machine they were assigned, etc., is difficult in large networks
DHCP was developed to make this process easier
DHCP server must be configured with a block of available IP addresses and their subnet masks
Clients must be configured to use DHCP
Broadcast request message is sent on boot
Client leases the address the server assigns to it
If no answer is received, in an APIPA-enabled OS, the computer assigns itself an address ( x.x)

14. IP Addressing
IP addressing is responsible for routing in TCP/IP environment.
Example:
IP address is 32 bits long (4 bytes)
Special IP addresses:
= Broadcast
127.xxx.xxx.xxx = Localhost
IP address is divided into 2 parts
Network Identification
Host Identification

15. Scope of Transmission
Hosts in same network (same Network ID) can be connected with switches/hubs
Router is required to transmit to hosts outside of network (different Network ID).
Broadcast messages can only be transmitted to hosts within same network (broadcast domain).

16. Types of IP Addressing
The demarcation point in the 32 bit address between network ID and host ID depends on addressing scheme:
Class Based Addressing generally uses a byte boundary as the dividing point
Classless Based Addressing uses a bit boundary.

17. Class Based IP Addressing
(Cisco – IP Addressing, n.d.).
Used less frequently now, CIDR preferred

18. Internet Protocol Version 6
Limitations with IPv4
32 bit address space is limited
No Quality of Service (QoS) support
IPv6 Features:
Incorporates IPSec
128 bit address
Auto-configuration
No IP address to assign
No subnet mask to determine
2 methods of auto-configuration
Stateless
Host creates its own IP address based on router information and MAC address
Simplest and most common
Stateful
Relies on DHCP server

19. IPv6 Address Scheme Hexidecimal grouped in 16 bit sections:
2001:1b20:302:442a:110:2fea:ac4:2b
Leading zeroes are eliminated
2 or more 16 bit fields of all zeros can be ignored:
2001:260:0:0:0:2ed3:340:ab (long form)
2001:260::2ed3:340:ab (short form)
IPv6 has 3 parts:

20. Other Protocol Suites Tomsho, Tittel, Johnson (2007)
Other protocol suites are sometimes used on older networks, where the need to change to TCP/IP is not warranted, or in environments suited to the suite’s features
NetBIOS/NetBEUI
Used primarily on older Windows networks
IPX/SPX
Designed for use on NetWare networks
AppleTalk
Used almost exclusively on Macintosh networks

21. References
Tomsho, Tittel, Johnson (2007). Guide to Networking Essentials. Boston: Thompson Course Technology.
Odom, Knott (2006). Networking Basics: CCNA 1 Companion Guide. Indianapolis: Cisco Press
Wikipedia (n.d.). OSI Model. Retrieved 09/12/2006 from
Cisco – IP Addressing (n.d.). IP Addressing. Retrieved 09/27/2006 from
IANA (n.d.) Abuse Issues and IP Addresses . Retrieved 11/11/06 from