From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by
Wendell Odom, CCIE No. ... Transmission Control Protocol/Internet Protocol (TCP
/IP).
NETWORKING CONCEPTS CET4773 | SPRING 2013 | FINAL EXAM REVIEW | DR. MENDOZA
COMPUTER NETWORKS CONCEPTS
HOW DO COMPUTER NETWORKS WORK?
Transfer data (files) from Computer to Computer (PC) Network interface card and media to connect PC How about more than two computers?
From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
Figure 1-5 Star Cabling to a Repeater
From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
HOW COMPUTER NETWORKS WORK Transfer files from Computer to Computer (PC) Network interface card and media to connect PC Hub repeats everything What is the problem? How to solve it?
Figure 1-6 The First Network Addressing Convention
From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
HOW COMPUTER NETWORKS WORK Transfer files from Computer to Computer (PC) Network interface card and media to connect PC Hub repeats everything Unique numeric address on each networking card—a six byte number – Addressable How to deploy a network to multiply offices, floors, and buildings?
Figure 1-7 Per-Floor Hubs, Connected Together
From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
THE FLINTSTONES NETWORK: THE FIRST COMPUTER NETWORK? Transfer files from Computer to Computer (PC) Network interface card and media to connect PC Hub repeats everything Unique numeric address on each networking card—a six byte number – Addressable Use hubs –even better, use switches– to connect cables in a star topology. Numbers are not easy to remember
NAME/ADDRESS TABLE
SUMMARY UNTIL THIS POINT • Ethernet networks use cards inside each computer. • The cards have unique numeric addresses • Ethernet cables connect PCs to Ethernet hubs—hubs that repeat each received signal out all other ports. • The cabling is typically run in a star configuration— in other words, all cables run from a cubicle to a wiring closet. • Applications such as the File Transfer Protocol (FTP) ask the underlying hardware to transfer the contents of files. • Users can use names—for instance, you might surf a website called www.certskills.com—but the name gets translated into the correct address.
NETWORKING MODELS
TCP/IP AND OSI
OBJECTIVES Networking Model Transmission Control Protocol/Internet Protocol (TCP/IP) • TCP • IP Open System Interconnection (OSI) reference model Comparison of TCP/IP and OSI Model
NETWORKING MODEL Networking Architecture or Networking Blueprint Comprehensive set of Documents • Protocols • Physical requirement Historically – Designed to prevent vendor specific networking solutions
TRANSMISSION CONTROL PROTOCOL/INTERNET PROTOCOL (TCP/IP) Defines and references a large collection of protocols that allow computers to communicate • Request for Comments • Concept of Layers
PROTOCOLS (TCP/IP)
TRANSMISSION CONTROL PROTOCOL (TCP) The TCP provides reliable transmission of data in an IP environment • TCP Connection Establishment • Positive Acknowledgment and Retransmission (PAR) • TCP Sliding Window • TCP Packet Format
INTERNET PROTOCOL (IP) IP contains addressing information and some control information that enables packets to be routed • IP in RFC 791, represents the heart of the Internet • IP has two primary responsibilities • providing connectionless, best-effort delivery of datagrams through an internetwork • providing fragmentation and reassembly of datagrams to support data links with different maximum-transmission unit (MTU) sizes
INTERNET PROTOCOL (IP) CONTINUED IP Packet Format
OPEN SYSTEM INTERCONNECTION (OSI) REFERENCE MODEL A 7 layer model, used extensively in early years of networking (1980’s) CCNA exam requires familiarity with each layer Used primarily to facilitate multivendor equipment interoperability Conceived and implemented by two international standards organizations • International Organization for Standardization (ISO) • International Telecommunication Union–Telecommunications Standards Sector (ITU-T)
OPEN SYSTEM INTERCONNECTION (OSI) REFERENCE MODEL (CONTINUED)
WAYS TO REMEMBER THE SEVEN LAYERS All People Seem To Need Data Processing (Layers 7 to 1) Please Do Not Take Sausage Pizzas Away (Layers 1 to 7) Pew! Dead Ninja Turtles Smell Particularly Awful (Layers 1 to 7)
COMPARISON OF TCP/ IP AND OSI MODEL
ENCAPSULATION
INTERACTION BETWEEN LAYERS
DATA
NETWORK DATA ENCAPSULATION
OSI MODEL SUMMARY
MODERN ETHERNET LAN
FUNDAMEN TALS OF LANS
OBJECTIVES An Overview of Modern Ethernet LAN Carrier sense multiple access with collision detection (CSMA/ CD) Ethernet UTP Cabling • Straight-Through • Crossover Introduction to Switches Ethernet Data-Link Protocols
AN OVERVIEW OF MODERN ETHERNET LAN The Institute of Electrical and Electronics Engineers (IEEE) 802 series of protocols for Ethernet Data link layer, the IEEE separates the functions into two sub-layers: • The 802.3 Media Access Control (MAC) sub-layer • The 802.2 Logical Link Control (LLC) sub-layer Most of the standards define a different variation of Ethernet at the physical layer, with differences in speed and types of cabling.
AN OVERVIEW OF MODERN ETHERNET LAN Today’s most common types of Ethernet
Figure 3-1 Typical Small Modern LAN
From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
HISTORY
Figure 3-2 Small Ethernet 10BASE2 Network From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
CARRIER SENSE MULTIPLE ACCESS WITH COLLISION DETECTION (CSMA/ CD) CSMA/CD logic helps prevent collisions and also defines how to act when a collision does occur. • A device with a frame to send listens until the Ethernet is not busy • When the Ethernet is not busy, the sender(s) begin(s) sending the frame. • The sender(s) listen(s) to make sure that no collision occurred. • If a collision occurs, the devices that had been sending a frame each send a jamming signal to ensure that all stations recognize the collision. • After the jamming is complete, each sender randomizes a timer and waits that long before trying to resend the collided frame. • When each random timer expires, the process starts over http://webmuseum.mi.fh-offenburg.de/index.php?view=exh&src=69
ALGORITHM
http://en.wikipedia.org/wiki/File:CSMACD-Algorithm.svg
ETHERNET UTP CABLING UTP cabling include either two or four pairs of wires. RJ45 Connectors and Ports
http://www.webopedia.com/TERM/U/UTP.html
RJ45 AND UTP
From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
STRAIGHT-THROUGH CABLE
http://www.ertyu.org/steven_nikkel/ethernetcables.html
CROSSOVER CABLE
Figure 3-9 Typical Uses for Straight-Through and Crossover Ethernet Cables From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
A HUB
Figure 3-10 Hub Creates One Shared Electrical Bus From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
INTRODUCTION TO SWITCHES
FULL DUPLEX
Figure 3-12 Full-Duplex Operation Using a Switch From CCENT/CCNA ICND1 640-822 Official Cert Guide, Third Edition by Wendell Odom, CCIE No. 1624 (ISBN: 1587204258) Copyright© 2012 Pearson Education, Inc.
ETHERNET DATA-LINK PROTOCOLS Unique Physical address Burned into NIC
SUMMARY The four most popular types of Ethernet LANs and some details about each • Ethernet • Fast Ethernet • Gigabit Ethernet (two types) The CSMA/CD logic Straight-through cable concept Crossover cable concept List of devices that transmit on wire pair 1,2 and pair 3,6 Structure of a unicast Ethernet address Key Ethernet addressing terms
