NW203 Test1 Ch1-3

Firewall, Proxy Servers, NAT, routers, switches

Tablets(iPads etc), laptops, notebooks, Smart/Super phones, Home appliances, Vehicles

• 1. Resource sharing
•     Data
•     Hardware resources
•     Internet connection
• 2. Communication and support toos
•     E-mail
•     remote control of computers
• 3. Security
•    Authentication mechanisms
•        Centralize(central login using Directory Services)
•    Authorization
•       -a way network validate who is and who is not allowed access to the network
•       -have access to certain parts of network

• -1969 by US Department of Defense
• -called ARPANET
• -connected 4 computer

• -client/server(C/S)
• -Directory service
• -peer-to-peer (P2P)

• -Connects multiple PCs (clients) to a single computer (server), which distributes data and resources to the network
• -Has centralized control over network security

• Is an enhancement that grew out of the traditional client/server network.
• Maintains in a centralized directory
• Windows (Active Directory / Domain Services)

• Are also known as workgroups.
• Smaller network.
• Contains peer servers
• –The PCs that act as both client and server

Token Ring: Packets of data pass around a network from PC to PC

ARCNET An outdated networking protocol used for office automation

Ethernet A widely popular network protocol that defines wired connections within a network. Most common in today’s networks

TCP/IP

• SNA (IBM System Network Architecture)
• IPX/SPX (Novell, originally required on NetWare)
• AppleTalk
• DecNet (Digital Equipment Corporation)
• + others
• NetBEUI used by MS-DOS and windows network

The process used by computers to establish connections to each other.(agree on the rules of communication)

Personal Area Network

• Intranet
• –Uses the same technologies as the Internet.
• –Only open to those inside an organization.

• Extranet
• –Uses the same technologies as the Internet.
• –Open to users outside the organization.
• –Accessed from the Internet.

• –Integration of voice, video, and data communication
• –Networks that were previously transmitted using separate networks will merge into a single, high speed, multimedia network

Application Service Provider.

• Companies the use ASP's rather than develop their own system.
• –Evolving into information utilities
• —companies that sell information for services
• –Cloud services

• Physical
• Data Link
• Network
• Transport
• Session
• Presentation
• Application

• Application
• Presentation
• Session
• Transport
• Network
• Data Link
• Physical

Application or Process (OSI Application, Presentation, Session)

Transport or Host-to-Host (same as OSI Transport)

Internet work or Network (same as OSI Network)

Network Access or Network Interface (same as OSI Data Link)

DoD model

Physical

RJ-45

They are the same except the Internet model has a Physical layer.

• –Protocol software components running on computer
• –Made of different protocols from protocol suite
• –Each layer performs functions, wrapping message content with control information

Manchester encoding.(it is unipolar)

• Unipolar
• Bipolar: NRZ(non return to zero)
•              RZ(return to zero)
• Manchester Encoding
•              used by ethernet

• –Data Link layer protocol
• –and Network layer protocol

• voltage level
• encoding method
• data rate(speed)

• 802.3 Ethernet
• 802.5 Token Ring
• 802.11 Wireless LANs
• 802.15 Wireless PAN (personal area network)
• 802.16 Wireless MAN(WiMax)

• Carrier-Sense Multiple Access/Collision Detection
• –Specifies access method used by Ethernet–Requires all devices to listen to cable before transmitting (carrier sense).
• –When line is clear, any device can transmit (multiple access)
• –If two devices transmit at same time:
•      collision occurs
•      Back off for random time period
•      both must retransmit (collision detection)

• –Advantages:
• Hardware relatively inexpensive, available.
• High speed versions:
•    –802.3x: 100Mbps Ethernet
•    –802.3z: 1Gbps Ethernet

• –Disadvantages:
• Performance can suffer as network size increases, increasing number of possible collisions

Collisions eliminated with switching

Connection Oriented - TCP(Transmission Control Protocol)

Connectionless - UDP(User Datagram Protocol)

32 bits(4 sets of 8)

Communications procedures used at the Data Link layer on all networks.

A random amount of time each system on a network must wait before attempting to transmit when a collision has been sensed.

Used interchangeably with Ethernet. Serves as the basis for how cable is accessed for communication. All devices must listen before it can transmit (carrier sense). Only one device on the network can transmit at a time. After the line is clear, any device can send its message (multiple access). If two computers transmit at the same time, a collision occurs and both must retransmit (collision detection).

Dynamic Host Configuration Protocol. Protocol and service used to automatically provide IP address and other TCP/IP configuration settings from a central host.

Internet Protocol. The protocol used to assign unique addresses to devices on the Internet.

A special type of unipolar signaling in which the signal is changed from high to low or from low to high in the middle of the signal.

Media Access Unit. A unit in a Token Ring topology which passes packets to computers on the network.

A communication method that allows multiple signals to transmit simultaneously across a single physical channel by varying length of transmission, frequency used, or both.

The group of protocols surrounding a data packet that is added and removed as the data stack moves through the layers of the OSI model.

Several network protocols grouped together, like TCP/IP.

Return to zero. This telecommunications code always returns to 0 volts after each bit before going to +5 volts (for a 1) or 5 volts (for a 0) for the next volt.

Nonreturn to zero. This telecommunications binary code schema represents 1s and 0s with separate significant voltage conditions (for example, 1 as positive voltage and 0 as no voltage). No other conditions are recognized in this code.

A portion of the IP address that identifies which part of the 32 bits is the host address and which part is the network address for the system.

Transmission Control Protocol The most common of all network protocol suites, the standard in today’s networks, and the protocol suite used for communication on the Internet. Provides connection-oriented packet delivery services that include error checking and sequence numbering, with the destination device responding with a receipt on packet delivery.

Noted by IEEE 802.11, defines communications between wireless clients (PC or server) to an access point. 802.11a,b,g, and n standards exist currently.

Wireless Personal Area Networks Describes short distance wireless networks used by individuals at home or office and includes PDAs, printers, smart phones, tablets and PCs. The 802.15 Wireless Personal Area Network standard is under development.

first bit is a 0

Value of the first octet is between 1 and 127 (127 loopback)

the first octet assigned, leaving the last three octets to be assigned to hosts

Intended for large corporations and government

first 2 address bit are with 10

–Value of the first octet is between 128 and 191

–The first two octets assigned, leaving the third and fourth octets to be assigned to hosts

–Intended for use in medium to large networks

first 3 address bits are 110

–Value of the first octet is between 192 and 223

–The first three octets

–These networks are limited to 254 hosts per network

–Intended for small networks

first 4 address bits are 1110

Value of the first octet is between 224 and 239

–Reserved for multicasting

first 5 address bits are 11110

–Value of the first octet is between 240 and 255

–Reserved for experimental use and can’t be used for address assignment

Class A addresses beginning with 10

Class B addresses from 172.16 to 172.31

Class C addresses from 192.168.0 to 192.168.255

The addresses in those ranges can’t be routed across the Internet

128 bit address size (16 bytes)

No class address like IPv4

Supports CIDR notation

Has many of the features of IPv4

Uses a different format for IP addresses

Can run alongside IPv4 without needing to change the Transport Layer or Network Access Layer

8 sets of 4 hexadecimal numbers

• A hexadecimal number needs 4 bits.
• 8*4*4 = 128

Application, Presentation, Session layers

Transport layer

Network

Data Link

Host-to-Host

Internet

Network Interface

–Internet Protocol (IP) Provides for network identification through addressing and connectionless delivery of packets.

–Address Resolution Protocol (ARP) IPv4Provides a device’s MAC address from its IP address.

–Reverse Address Resolution Protocol (RARP) IPv4Provides a device’s IP address when the MAC address is known.

–Internet Control Message Protocol (ICMP)A management and troubleshooting protocol

–NDP (Neighbor Discovery Protocol) IPv6Resolves MAC addresses plus more

-a Network layer protocol

–Internet Protocol (IP)

Provides for network identification through addressing and connectionless delivery of packets.

• Network layer protocol
• –Address Resolution Protocol (ARP)
• IPv4Provides a device’s MAC address from its IP address.

• –Reverse Address Resolution Protocol (RARP) IPv4
• Provides a device’s IP address when the MAC address is known.
• Network layer protocol

• –Internet Control Message Protocol (ICMP)A management and troubleshooting protocol
• Network layer protocol

• –Internet Control Message Protocol (ICMP)A management and troubleshooting protocol
• Network layer protocol

• –NDP (Neighbor Discovery Protocol) IPv6Resolves MAC addresses plus more
• Network layer protocol

• –File Transfer Protocol (FTP)Protocol, service, and application that provides reliable file transfer between TCP/IP hosts.
• Application layer protocol

• –Trivial File Transfer Protocol (TFTP)
• Used for file transfer over the Internet using UDP but requiring acknowledgement (through TFTP) for each packet before the next is sent
• Application layer protocol

• –Simple Mail Transfer Protocol (SMTP)Protocol used to transfer e-mail messages between computers using TCP as its delivery protocol
• Application layer protocol

• –Hypertext Transfer Protocol (HTTP)Used to access Hypertext Markup Language (HTML) files (web pages) over the Internet or through an intranet
• allowing for rapid, reliable data exchange
• Application layer protocol

• –Domain Name System (DNS)Protocol and service used for host name to IP address resolution
• Application layer protocol

• –Telnet (unsecure)Protocol and application that provides remote terminal emulation services in clear text
• Secure version is ssh.
• Application layer protocol

• –Dynamic Host Configuration Protocol (DHCP)Protocol and service used to automatically provide IP address and other TCP/IP configuration settings for host computers
• Application layer protocol

• –Simple Network Management Protocol (SNMP)Protocol enabling remote configuration, monitoring, and management of network devices, services, and resources
• Application layer protocol

The process of adding a header and a trailer to information as the data passes from computer to computer over a network

A set of information added to the beginning of a data packet

–A set of information added to the end of a data packet

• The MAC address is permanently hard-coded on the NIC by the manufacturer.
• It is a unique hexadecimal address with six pairs of hexadecimal digits and is not duplicated anywhere in the world. The first six digits are assigned to the NIC manufacturer. The last six are a unique value assigned by the manufacturer
• –Conventional MAC address 48 bits (IPv6 – 64 bit MACS)

Network Adapter or Network Interface Card

• The service responsible for determining which computer is sending and which is receiving at any given time throughout the session.
• Simplex -Data flows in only one direction.
• Half duplex -Data flows in both directions,but only in one direction at a time.
• Full duplex-Data flows in both directions at the same time.

Time to Live (TTL) An IP header field whose value is used to limit the lifespan of a datagram based on the number of routers(hops) it crosses.

Acknowledgement message sent by the receiving computer in a connection oriented transmission.

The process that limits the number of transmission ssent at one time to avoid overloading the receiving device.

Authentication mechanisms are ways that the network can validate who is and who isn’t allowed access to the network.

A private network that allows for specific external users to access it over the Internet.

An intranet is a LAN that uses the same technologies as the Internet, such as using web servers to facilitate internal communications, but it’s open to only those inside the organization.

• Layer 7 (highest layer)
• Allows the end user access to the network by providing a set of utilities for application programs.
• Five categories of service:
•      Files service
•      E-mail services
•      Network printing services
•      Application services
•      Database services

• Layer 6
• Data presentation - Formatting data so that it is readable by the recipient.
• Data compression - Resizing the data to speed transmission.
• Data encryption - Making data unreadable by unintended recipients.

• Layer 5
• Responsible for initiation, maintenance, and termination of each logical session between computers. Session layer is also responsible for session accounting.
• Dialog control: –Simplex, half-duplex, full duplex.
• Data separation:–Inserting markers in packets to recover from loss of packets or other problems.

• Layer 4
• deals with end-to-end issues such as procedures for entering and exiting from the network
• establishes & terminate logical connections for data transfer
• breaks larger samples into manageable pieces and flow control

• Two types of transmission:
• Connection-oriented transmission (TCP)
• -It is reliable
• -It allows for relatively slow communication
• -Packets are re-sent if a packet is unrecognizable or is not received

• Connectionless (UDP)
• -Does not acknowledge receipt of the packet
• -Provides a relatively faster connection
• -Packets are not re-transmitted

• Layer 3
• Responsible for addressing and delivery of packets (datagrams)
• IPv4 and IPv6
• Performs routing:
• –Finding a path through routers so packets are delivered to the correct network and then the correct computer

• Each computer has:
• –A physical address - coded on network card
• –A logical address - assigned through networking software, used by the Network layer

• Layer 2
• Manages the physical transmission circuit in the Physical layer
• MAC Addresses (Hardware Address or Physical Address)
• Transforms it into a circuit that is free of transmission errors by performing error detection, correction, and retransmission.

Converts data packets into frames. A frame is the data packet plus the encapsulating information, including layer 2 addresses.

The Data Link layer has two sublayers.

Logical Link Control (LLC) sublayer. The LLC sublayer provides the interface between the media access method (for physical network traffic control) and Network layer protocols

Media Access Control (MAC) sublayer. The MAC sublayer is responsible for the connection to the physical media and physical address

• Layer 1
• Controls the rules for data transmission
• Including electrical currents, types of cables, and transmission speed
• NIC operates at this level and converts data into transmission signals

• Manages the way a device connects to the network media
• All components are specified at the Physical layer