CSIS 261

OSI Model #1

Data is sent in Bits, 1 and 0. Bits= binary digit

-in the OSI model. data can be called packets, or frames or segments.

-source address specifies the identity of the computer sending the packet

-destination address specifies the identity of the computer designated to receive the packet

-computers can take turns sending packets.

-if packet is lost only small amount of data must be retransmitted.

-data can take different paths.

-/MEDIA/- coax, 10base5 thicknet, UTP, Fiber Optic Cable Connectors.

=OSI Model=

-reduces complexity

-standardizes interfaces

-facilitates modular engineering

-ensures interoperable technology

-accelerates evolution

-simplifies teaching and learning

+Application-->user interface

+Presentation-->Data presentation and encryption

+Session-->Keeping different applications data separate

+Transport-->End-to-end connections

+Network--->Addresses and best path

+Data Link-->Access To media

+Physical-->Binary Transmission

1.Physical- Basic Hardware componedts for networks. RS-232 specific

2.Data Link- Frame format, transmitting frames over the net

3.Network- Addressing assignment, Packet forwarding methods.

4.Transpoort-Transfer Correctness

5.Session- 4establishing a communication session, security , authentication...passwords

6.Presentation-computer represent data in different ways thus the protocol need to translate the data to and from the local node.

7.Application-Specifations for applications.

7.Application

6.Presentation

5.Session

These 3 are know as the Applications Layers.

1.Physical

2.Data Link

3.Network

4.Transpoort

The first 4 are known as the data flow layers because they control the physical delivery of messages over the network.

Layer 6: Presentations

-ensures the information sent by the application layer of one system is readable by the application layer of another

-translates between multiple data representation formats by using a common data representation format

-concerned with data structures and negotiation of data for syntax

-Handles compression and encryptions.

Layer 5: Sessions

-establishers, manages, and terminates sessions between applications.

-synchronizes dialog between presentation layer entities and manage their data exchange

-offers provisions for efficient data transfer, class of service, and exceptions reporting of session, presentation and application layer problems

-manages data exchange between presentation layer entities

Layer 4: Transport

-concerned with transportation issues between hosts

-data transport reliability

-establish, maintain, terminate virtual circuits

-fault detection and recovery

-information flow control

-segments and reassembles data into the data stream

-concerned with how reliable transport over internetwork is accomplished

-responsible for reliable network communication between end nodes a provides mechanisms for the establishment maintenance and termination of virtual circuits transport fault decections and recovery and information flow control

Layer 3: Network

-provides connectivity and path selection between tow end systems

0domain of routing

-provides connectivity and path selection between tow end systems where routing occurs this may be located on geographically separated networks.

Layer 2: Data link

-provides reliable transfer of data across media

-addressing network topology err notification flow control

-is concerned with physical (as opposed to logical) addressing network topology network access, error notification, ordered delivery of frames , and flow control

Layer 1: Physical

-wires, connectors, voltages, data rates.

-defines the electrical and functional specifications for the link between end systems(including media)

-defines voltage levels, timing of voltage changers , physical data related, maximum transmission distances, physical connectors, and or the similar attributes.

Transmission Encapsulated

1.Build the data

2.Packeage the data for end to end transport.

3.Append(add) the network address to the header(includes control information)

4.Append(add) the local address to the data link header

5.Translates into bits for transmission.

Peer to Peer-moves strait from one side to the other.

The Department of Defense(DoD) created the TCP/IP reference model because it wanted a network that could survive and conditions, even a nuclear war.

TCP/IP has 4 layer model

Application

Transport

Internet

Network Access

Transport- offers QoS, reliablility flow control and error correction., TCP is connections oriented protocol.

Internet- is to send sources packets for many network on internet work and have them arrive at the destination independent of the path and networks thy took to get there. IP(governs the internet layer) best path determination and packet switching occur at this layer.

Network Access-AKA Host to network layer. It is the layer that is concerned wit all of the issues that ip packet require to actually make a physical link and then make another physical link

CSIS 261-2

UTP - Unshielded Twisted Pair- most commonly used in Networking.

-Speed and throughput: 10Mb - 100Mb - 1gigbit

-Average $ per node : least expensive ($100 per drop)

-Media and connector size L small

-Max cable lengths 100m-385ft (short as media)

Relies on cancellation to reduce EMI

Precise specification for the number of twist pre braid.

Resistance = 100ohms/100m

(AWG-American Wire Gauge)

Advantages

-Easy to install

-Least expensive

-Small Diameter

-Proper Termination procedures insures reliable connection

Disadvantages

-More prone to EMI/RFI than any other cable

-Shortest allowable length of any other cable

Shielded Twists Pair (STP)

-Speed and throughput: 10Mb - 100Mb - 1gigbit

-Average $ per node: Moderately Expensive

-Media And connector Size-Medium to Large

-Max cable lengths 100m-385ft (short as media)

Same advantages and disadvantages as UTP

-Foil shield proved greater protection against EMI & RFI

-Increased Cost Of Cable

Coaxial Cable

-Speed And throughput: 10-100Mbps

-Average $ per node: Inexpensive

-Media and connector size: Medium

-Maximum Cable length:RG6-500m/1500ft RG8-800m(Medium as media)

Advantaging

-Longer Cable than UTP, STP

-Cheaper than using fiber as a backbone.

-Technology is well known (Cable TV)

-Better at reducing EMI than UTP or STP

Disadvantages

-Thickness of the cable

-Copper Shielding must be grounded properly at both ends

Fiber Optics

-Speed And throughput: 100+ Mbs

-Average $ per node: Most expensive

-Media and connector size: Small

-Maximum Cable length: up to 3 km

-Single mode: One stream of laser generated light 3Km

-Multimode: Multiple streams of LED- Generated Light 2Km

ST,FC,MRJT

Advantages

- Runs longer than any other cable 3km

-Higher data rates than any other Cable (1Gbps@300Mhzt)

-No EMI/RFI

Disadvantages

-Expensive

-Difficult to install

Standards

ISO-Inter4nations Standards Organization

IEEE-Instituted of Electrical And Electronic Engineers

TIA-Telecommunications Industry Association

EIA-Electronics Industry Association

UL- Underwriters Laboratories (Industry Standards Testing People)

TIA & EIA

-TIA & EIA - issues standards together for technologies that involve both telecommunication s& electronics.

-TIA & EIA - Have had the greatest Impact on networking media standards

-TIA & EIA - 568B is the standards we will use when making our cables.

-Specified cable performance and terminator in procedure for horizontal cablings

-Six Categories (CAT 1 to CAT 6)

-CAT 5 media includes UTP, STP, Coaxial and Fiber.

-CAT 5 UTP is most common

Horizontal and Vertical Cabling

-Horizontal cabling includes all cabling that runs form work areas to the wiring closet

-vertical cabalist another name for backbone cabling.

Horizontal Cabling (TIA/EIA 568A)

=Node-Outlet:3m

=Outlet-Horizontal Cross Connect:90m

=HCC-Hub/Router:6m

IEEE 802.3(10Base-T Ethernet)

-Emerged out of Hawaii's need to connect islands

-Has become the 'chosen' LAN technology

-Includes specification for both Layer 1 & Layer 2

-Your Skill in 802.3 implementation will migrates to 100Base-TX & 1000Base-T

-Passive Components(DO not add Energy)

-Cabling

-Connectors

-Jacks

-Patch Panels

-Active Components(Add Energy)

-Repeaters, Transceivers, & Hubs.

Passive Components

10Base-T Cabling

-Cat 5 Cable is a Layer 1 component

-It Carries bits!

-CAT 5 Is a 10Base-T standard Able

-The Twist per inch reduces the EMI/RFI

-Standard 10Base-T Termination is a Registered Jack - 45 (RJ-45)

-Similar to the phone plug except the RJ-45 has 8 pins instead of 4 pins.

-Reduces Noise, Reflection , & mechanical stability problems

10Base-T Jacks (Conductors)

-RJ-45 Jacks Have 8 conductors that match the cables

Patch panels

-Patch Panels are used to connect workareas togeather

-one side ahs a place ahs a RJ-45

-The back side ahs punch down block that provide connectivity (110 Punch down)

Collisions

-Collisions occur in broadcast topologies where devices are attached to shared media.

-Shared media is like shared highways.

-***Layer 1 device will not solve collision problems.***

-Lay 1 devices will simply extend collision domains.

Collisions Domains

-Collision Domains Are the area where collisions occur.

-Layer 1 devices will not separate (segment0 collision domains.

-How Many Collision Domain with...

-a repeater? A: We have 1 collision domain

-a hub? A: we have 1 collision domain

-a repeater and a hub? A: we have 1 collision domain

Collisions Domains Segmentation

-Segmentation is the process of dividing a collision domain into two or more collision domains.

-Layer 1 device will not segment a collision domain

-The only way to segment a collision domain is to use a device that can filter network traffic.

-Filtering devices: Routers, switches, bridges,

Topology

Extend Star-Each end node of the core act as it own star topology.

Hierarchical Topology

-Also called a tree topology

-No Central node

-Two types: 1.Binary Tree - each n