Transcript ITEC 370 Network Media George Vaughan

ITEC 370
Network Media
George Vaughan
1
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.
2
TCP/IP and OSI Models
TCP/IP and OSI Models (OSI-Model, n.d.) and (Tomsho, 2007)
TCP/IP
Layers
Application
PDU
Data
OSI Layers
7 Application
6
5
Transport
Segments 4
Network
Packets
3
Link
Frames
2
Function
Network process to application,
Initiates or accepts a request to transfer
data
Presentation Adds formatting, display, and
encryption of information
Session
Adds communication session control
information, Login/Logout
Transport
Adds End-to-end connections and
reliability, re-sequencing, flow control
Network
Path determination and logical
addressing (IP), translates MAC
address to logical address
LLC Adds error checking and physical
Data
Link
addressing (MAC & LLC)
Devices - Apps
Standards
Browsers,
servers,
Gateways
Gateways
HTTP, SNMP,
FTP, Telnet
DNS,
Gateways
Gateways
NetBIOS
Routers
IP, ICMP,
ARP, NetBEUI
Switches,
Bridges, NICs
802.3, 802.11,
FDDI
ASCII, MPEG
TCP, UDP
MAC
Bits
1 Physical
Media, signal and binary transmission, Hubs,
sends data as a bit stream
Repeaters
10Base-T, T1,
E1
3
Cable Characteristics
• Bandwidth – Bits per second
• Maximum Cable Length – Length before signal is unintelligible
due to attenuation.
• Maximum Number of Segments – Maximum number of
segments (including signal regeneration equipment) before
signal is too late at destination.
• Maximum Number of Devices per Segment – Devices also
increase attenuation (insertion loss).
• Interference Susceptibility – Electromagnetic Interference
(EMI) and Radio Frequency Interference (RFI).
• Connection Hardware – Cost, Complexity
• Cable Grade – Cladding or Sheath Material, Fire Codes,
Usable in walls or plenum.
• Bend Radius – Degrees per feet
• Material Cost
• Installation Cost
4
Boadband and Baseband
Communication
• Baseband
– Uses a single frequency to transmit digital pulses.
– Half Duplex per strand (2 strands for Full Duplex).
– Bi-directional – one strand can be used for sending and
receiving.
– Repeaters and switches are used for signal regeneration.
– Used in Ethernet
• Broadband
– Analog Transmission
– More than one frequency can be on one strand
– A single strand can support Full Duplex
– One frequency is unidirectional – 2 strands (Dual-Cable
Broadband) or 2 frequencies (Mid-split broadband)
needed for Full Duplex.
– Amplifiers used to strengthen signals.
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Cable Types - Coax
•
•
•
•
Used by Cable TV
No longer used in LANs
Interference: better than twisted pair, worse than fiber
Used in early Ethernet Applications
– 10Base5 (10 Mbps, Baseband, 500 meter
segments) - Thicknet
– 10Base2 (10 Mbps, Baseband, 200 meter
segments) - Thinnet
– Used in Physical Bus Ethernet networks
• Cable Modem Applications
– 75 ohm, RG-6 (Radio Grade)
– 256 Kps up to 1 Mbps
– Shared resource: more connections = lower
bandwidth
6
Coaxial Cable (continued)
Tomsho, Tittel, Johnson (2007)
7
Coaxial Cable in Cable Modem Applications
(continued)
Tomsho, Tittel, Johnson (2007)
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Cable Types – Twisted Pair
•
•
Twisted Pair (TP) – strand pairs are twisted around each other –
minimizes interference and crosstalk.
Unshielded Twisted Pair (UTP)
– Ethernet: 10BaseT (10 Mbps, Basedband, UTP) – requires
physical Star topology (Odom, 2006)
– UTP most popular LAN cable
– Also used in Phone Systems
ANSI/TIA/EIA 568 Standards (Tomsho, 2007)
Category
1
2
3
4
5
5e
6
7
Bandwidth Signaling Rate
4 Mbps
10 Mbps
16 Mbps
100 Mbps
1 Gbps
1 Gbps
1 Gbps <
16 MHz
20 MHz
100 MHz
100 MHz
200 MHz
600 MHz
Purpose
Telephones, Not suitable for data
Token Ring, ARCnet
Telephones and 10BASE-T
Token Ring, 10BaseT
100BaseT, ATM (also 1000BaseT)
Ethernet
Ethernet
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Twisted-Pair Cable
Tomsho, Tittel, Johnson (2007)
10
Cable Types – Twisted Pair
•
•
•
•
•
•
Shielded Twisted Pair (STP) – similar to UTP, except that braided pair
is contained in a foil.
No standard exists for STP.
UTP and STP usually use RJ-45 (Registered Jack) telephone
connectors.
RJ-45 contain 8 contacts, although, only 4 are used, 2 for transmit (+/) and 2 for receive (+/-)
2 different standards for wiring an RJ-45 connector: TIA/EIA 58A and
TIA/EIA 58B
Cable Wiring Strategies (Odom, 2006)
– Straight Through Wiring:
• Pins (1,2) -> Pins (1,2) and Pins (3,6) -> Pins (3,6)
• Used for connecting PC’s to hubs or switches
– Crossover Wiring:
• Pins (1,2) -> Pins (3,6) and Pins (3,6) -> Pins (1,2)
• Used for connecting PC’s to PC’s or switches to switches
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Twisted-Pair Cable (continued)
Tomsho, Tittel, Johnson (2007)
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Cable Types – Fiber Optic
• Uses light rather than EM signals to transmit
information.
• Not susceptible to EMI or RFI
• Does not broadcast or radiate EM signals
• Extremely secure to electronic eavesdropping.
• Very High Bandwidth: 10 Gb/s and greater
• Maximum cable segments on the order of miles.
• More fragile, less flexible than copper.
• More expensive.
• Each strand passes signals in one direction.
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Fiber-Optic Cable
Tomsho, Tittel, Johnson (2007)
14
Fiber-Optic Cable (continued)
Tomsho, Tittel, Johnson (2007)
15
Single and Multi-Mode Fiber
• Information on this slide comes from (Odom, 2006)
• Multi-Mode:
–
–
–
–
Used with LEDs
LEDs spread light in multiple angles
LED light doesn’t travel as far as laser
Thicker core to absorb angular LED light
• Single-Mode
–
–
–
–
Used with Lasers
Lasers don’t spread light – single direction
Thinner core
Laser light travels further than with LED source
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Cable Type Comparisons
• Comparison of cost and performance of
different cable types (Tomsho, 2007)
Type Max Length Bandwidth Installation Interference
Cost
UTP
100 m
10-1000 Mb/s Easy
High
Cheapest
STP
100 m
16-1000 Mb/s Moderate Moderate
Moderate
10Base2 185 m
10 Mb/s
Easy
Moderate
Cheap
10Base5 500m
10 Mb/s
Hard
Low
Expensive
Fiber
2-100 km 10 Gb/s
Moderate None
Most Expensive
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Cable Considerations
• Plan network to separate light/moderate
users from heavy users.
• Plan network to separate local traffic from
backbone traffic
• A mixture of TP connected by hubs which
are then interconnected by coax or fiber
give TP greater reach
• Need to consider existing cable plant.
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Structured Cabling
• Defines cable plant organization (TIA/EIA 568)
• Work Area work station environment, patch cables (<6
meters).
• Horizontal Wiring cabling from work area to
Telecommunications Closet (<90 meters)
• Telecommunications Closet (TCs) patch panel, hubs,
switches.
• Equipment Rooms servers, switches, routers
• Backbone Cabling that connects equipment rooms, TCs.
Fiber often used.
• Entrance Facilities location where leased lines meet
Enterprise network.
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Telecommunications Closet
Tomsho, Tittel, Johnson (2007)
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Wireless LANs (WLAN)
• Standards are defined by Institute of Electrical and
Electronics Engineers (IEEE)
• IEEE 802.11 networking characteristics is similar to
Ethernet (IEEE 802.3)
• Characteristics of 802.11(IEEE 802.11, n.d.)
Type
Release
Date
802.11b 1999
Frequency
2.4 GHz
Data Rate
(Typical)
6.5 Mbps
Data Rate
(Max)
11 Mbps
802.11a 1999
5 GHz
25 Mbps
54 Mbps
802.11g 2003
2.4 GHz
25 Mbps
54 Mbps
Range (Indoor)
~30 meters (~100 feet)
~30 meters (~100
feet)
~30 meters (~100
feet)
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The Wireless World (continued)
Tomsho, Tittel, Johnson (2007)
22
Wireless MAN: The 802.16 Standard
Tomsho, Tittel, Johnson (2007)
• One of the latest wireless standards, 802.16 Worldwide
Interoperability for Microwave Access (WiMax), comes in
two flavors: 802.16-2004 (previously named 802.16a), or fixed
WiMax, and 802.16e, or mobile WiMax
– Promise wireless broadband to outlying and rural areas,
where last-mile wired connections are too expensive or
impractical because of rough terrain
– Delivers up to 70 Mbps of bandwidth at distances up to 30
miles
– Operates in a wide frequency range (2 to 66 GHz)
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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.). IEEE 802.11. Retrieved 09/10/2006 from
http://en.wikipedia.org/wiki/802.11a
Wikipedia (n.d.). OSI Model. Retrieved 09/12/2006 from
http://en.wikipedia.org/wiki/OSI_Model
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