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Chapter 6 Local Area Network Hardware LAN Technology Architecture Network Interface Cards Wiring...
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Transcript of Chapter 6 Local Area Network Hardware LAN Technology Architecture Network Interface Cards Wiring...
Chapter 6Local Area Network Hardware
• LAN Technology Architecture
• Network Interface Cards
• Wiring Center
• LAN Switches
• Media
LAN Technology Architecture
• Shared-media LAN
• Switched LAN
Shared- Media LAN
• Sharing available bandwidth among all devices
• 100BaseT, 100VG-Any-LAN, isochronous Ethernet
Switched LAN
• Dedicated (guaranteed) bandwidth to switch connected devices (point-to-point)
• Limited number of simultaneous point-to-point connections
• Replace the media-sharing LAN for more bandwidth
Full-Duplex Network Architectures
• Special type of switched LAN
• Full-duplex Ethernet, full-duplex token ring, full-duplex FDDI
• Full-duplex Ethernet NICs, full-duplex NIC drivers, and full-duplex Ethernet switches
Network Interface Cards (NICs)Functions
• Physical link between devices
• Pass data between devices
• Determine the network architecture and protocol
NICs - Technology Analysis• Bus Type
– ISA, EISA, MCA, NuBus (Apple), PCI, PCMCIA, Sbus (Sun)
– Internal/external or external interface to parallel port
• Data transfer technique– Bus-mastering DMA (direct memory access)
– DMA(direct memory access)
– Shared memory
– Program I/O
• Media interfaces (cables & connectors)
• Network drivers
• Management tools
• Other hardware requirements– On-board processor capabilities
– On-board memory
– System memory requirements
Bus Types
• Industry Standard Architecture (ISA): 8-bit or 16-bit
• Microchannel Architecture (MCA): 32-bit• Extended Industry Standard Architecture (EISA):
8-bit, 16-bit, 32-bit• Local bus
– Video Electronics Standards Association (VESA local bus or VL-Bus)
– Peripheral Component Interconnect (PCI local bus)
• Advanced graphic port by Intel
NICs - Trends
• Dual-speed cards: 10/100 Mbps
• Integrated or on-board NICs
• Multiport NICs
• On-NIC virus protection and security
• Integrated repeater modules (up to seven devices)
• Full-duplex mode
• Performance improvement
NIC Drivers
• Functions: communication between NIC and PC’s operating system
• Types:– Monolithic drivers– Multiprotocol network interface card drivers
• NDIS (network driver interface specification) by Microsoft & 3Com
• ODI (open data-link interface) by Novell & Apple
– PCMCIA (PC Card or CardBus) drivers: card and socket services (CSS)
PCMCIA
• Personal Computer Memory Card Interface Association
• People Can’t Master Computer Industry Acronyms
Wiring Center
• For Shared-media LAN
• Types– Stand-along hubs– Stackable hubs– Multistation access units– Enterprise hubs
Stand-along Hubs
• Repeaters– Retiming & regenerating digital signals– Linking devices or LAN segments of similar
network architecture
• Hubs– Subset of repeaters– Connect single devices to its ports– Concentrator or intelligent concentrator
Stackable Hubs
• Cascading ports for hubs
• Specialized hub-to-hub cables
• Expandability and manageability
• Stackability ranging from 4 to 20
Multistation Access Units
• MAU: token ring hub
• Shielded twisted pair with Type 1 connectors
• Eight ports with additional ports: RI (ring in) & RO (ring out) for cascading
• Active-management MAUs with identifying and removing malfunctioning token ring adapters
Enterprise Hubs
• Modular concentrators or network in a box• Modular design and chassis-based architecture• Hot-swappable: inserting and removing module
with power on• Types of modules
– Ethernet, token ring, & FDDI port modules
– Management modules: security, encryption, authorization modules
– Internetworking modules: router & bridge modules
– Multiple power supplies for redundant power
• Media: UTP, STP, thick or thin coax, & fiber
Hub Management
• Software– Local hub management software– Enterprise network management software: HP’s
Open View, IBM’s NetView, Sun’s SunNet Manager, Novell’s NMS
• Standard protocol– Simple network management protocol (SNMP)– Management information bases (MIB)– Remote monitoring (RMON) MIB
Wiring Center Analysis
• Expendability
• Reliability
• Network architecture
• Media
• Internetworking: WAN, LAN, different types
• Management
Wiring Center Management
• Operating system
• Faults
• Alarms
• Statistics
• Security
• Remote
• SNMP
LAN Switches: Architectures
• Stand-alone switches or slide-in modules for enterprise switches:– Ethernet switches– Token ring switches– FDDI switches– Fast Ethernet switches
• Super-Switches or Mega-Switches support– Multiple different LAN– ATM– WAN
LAN Switch Methods• Cut-through switches
– Fast– No error checking– Retransmitting
• Store-and-forward switches– Slow– Error checking
• Error-free cut-through switches– Error checking– Switch between cut-through & store-and-
forward depend on line condition
Switch Management
• Flow control– Buffers– Backpressure: false collision detection signal
• Monitoring– Port mirroring– Roving port mirroring– Simultaneous RMON view using a shared
memory multigigabit bus
LAN Switch Analysis
• Switching methods: cut through, stored and forward, error free stored and forward
• Network architecture: Ethernet, token ring, FDDI, etc
• Port configuration and connection: single device or multiple devices
• Full-duplex
• Internetworking: routing or bridge or both
• Management: SNMP
ATM for LAN
• IP over ATM– TCP/IP protocol stack to employ ATM services
• LAN emulation– A translation layer to use ATM services
LAN Media Alternatives
• Not twisted pair
• Unshielded twisted pair
• Shielded twisted pair
• Coaxial cable
• Fiber
• Microwave radio
• Satellite
• Infrared
Not Twisted Pair: Phone Wire
• Four-conductor station wire (RYGB)– Not for data transmission
• Flat gray modular wire or gray satin or silver satin– Data over short distance
Unshielded Twisted Pair • 22, 24, 26 American wire gauge(AWG)• Twisted pair or unshielded twisted pair (UTP)• Electrical noise & other interference• Electrical Industries
Association/Telecommunications Industries Association (EIA/TIA): 5 grades (Cat 3 & Cat 5: data grade)– Attenuation
– Near-end crosstalk (NExT)
• Category 6– Foil-twisted pair cable
– Data rate: 600 MHz
UTP Installation Mistakes
• Untwisting more than max 13 mm to wall plates or punch-down block
• Exceed maxi bend radius (increase cross talk)
• Tight wires too tight (cross talk)
Shielded Twisted Pair
• Pros:– Less interference– Faster speed
• Cons:– More expensive– Physically larger and difficult to connect to a
terminating block
Coaxial Cable
• Pros:– Large bandwidth (400 - 600 MHz)– High capacity– Less interference– Good for noise environment
• Cons:– Tapped easy (security problem)– Bulky to install
Fiber - I• Types:
– Single mode: more expensive and capacity
– Multimode graded index: medium expensive and capacity
– Multimode or multimode step index: less expensive and capacity
– Inexpensive plastic or copper
– Expensive glass
• Pros:– High bandwidth
– No interference
– No crosstalk
– Small physical size and light weight
– Very secure
• Cons:– Repeater for long distance
– Expansive
Fiber - II
• Standard– Synchronous optical network (SONET) in US– Synchronous digital hierarchy (SDH) in Europe
• Main cable - TAT-8– 6 fiber optic– 2 pairs for voice, video, and data– 1 pairs for backup– Regenerator every 43 miles
Microwave Radio - I
• Characteristics– Long distance– 4-28 gHz frequency range– Straight line transmission– 20-30 miles between transmission towers– Radio license by FCC
Microwave Radio - II
• Pros:– Analog or digital signals
– For voice, data and television signals
– Long distance
• Cons:– Interference by heavy rain
– Straight line transmission
– Security
• Vendors– Motorola
– Rockwell Communication Systems
Satellite• Characteristics:
– Microwave radio transmission
– Uplink and downlink
– Three satellites for the earth
• Pros:– Analog or digital signals
– For voice, data and television signals
– Long distance
• Cons:– Security and encryption
– Propagation delay
Infrared
• Light waves
• Line of sight
• Wireless communication between nearby equipment
Circuit Ownership
• Private circuits
• Leased circuits
• Bypass
• Switched (dial-up) circuits
• Selection criteria– Cost, speed, availability, reliability,
maintenance, users’ requirements
Circuit Identification
• Blue prints and document circuit and equipment
• Circuit number to each circuit for identification
Assignment
• Review chapters 5-6
• Read chapter 7