Network Guide to Networks 5th Edition

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Network Guide to Networks5th Edition

• Chapter 6
• Network Hardware

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Objectives

• Identify the functions of LAN connectivity
  hardware
• Differentiate between network devices such as,
  NICs, hubs, bridges, switches, and routers
• Explain advanced features of switches and
  understand popular switching techniques,
  including VLAN management
• Explain the purposes and properties of routing

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Connectivity Hardware

• Layer 1 Devices
• Repeater
• Hub
• Layer 2 Devices
• Bridge
• Switch
• Layer 3 Device -- Router

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NICs (Network Interface Cards)

• Enable transmission/reception of data to/from
  network
• Physical layer and Data Link layer functions
• Issue data signals
• Assemble and disassemble data frames
• Interpret physical addressing information
• Determine right to transmit data

Network Guide to Networks, 5th Edition
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NICs (contd.)

• Smart hardware
• Perform prioritization
• Network management
• Buffering
• Traffic-filtering
• Do not analyze information added by Layers 3 - 7
  

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Connectivity Hardware

• Layer 1 Devices
• Repeater
• Hub
• Layer 2 Devices
• Bridge
• Switch
• Layer 3 Device -- Router

Network Guide to Networks, 5th Edition
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Repeaters

• Simplest connectivity device, operating at
  Physical Layer
• Has no means to interpret data
• Just regenerates signal
• Limited scope only one input port, one output
  port
• Suitable for bus topology networks
• Extend network inexpensively
• Rarely used on modern networks

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Hubs

• Aka multi-port repeater
• Repeat signal to all nodes (broadcasts)
• Bandwidth is shared among all nodes
• More nodes leads to
• transmission errors
• slow performance
• Limited use in modern LAN

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Bridges

• Connect two or more network segments
• Of same Layer 1 2 technologies
• Of same Layer 1, but different Layer 2
  technologies
• Of different Layer 1, but same Layer 2
  technologies
• Of different Layer 1 and different Layer 2
  technologies
• Use MAC addresses to determine where to forward
  incoming frames
• Almost non-existent today

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• Advantages over repeaters and hubs
• Add length beyond maximum segments
  limits(creates multiple collision domains)
• Improve network performance
• Disadvantage increased latency

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Switches

• Micro-segment network (no shared bandwidth)
• Use MAC addresses to determine where to forward
  incoming frames
• Replacing your hubs with switches will
• Ease congestion
• Increase performance
• Provide (slightly) better security

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Switches

• Advantages over bridge
• Better bandwidth use
• More cost-efficient

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Two Basic Switching Methods

• Cut-Through
• Switch begins forwarding frame before it has been
  completely received.
• Fast, but cannot detect corrupt/damaged frames
• Store-and-Forward
• Switch waits until entire frame has been received
  and verified before forwarding.
• Reliable, but slower than cut-through

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VLANs

• Logically separate networks within networks
• Groups ports into different broadcast domains
• Removes physical limitations of cableplant

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VLANs
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VLANs

• Reasons for using VLANs
• Separating user groups
• Isolating connections
• Identifying priority device groups
• Grouping legacy protocol devices
• Broadcast containment for performance and/or
  security improvement

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VLAN Trunking

• Single physical connection between switches
  and/or router(s) caries data from multiple
  logical VLANs
• Inter-VLAN communication requires a router
• Advantages of VLAN trunking
• Economical use of routers and switches
• Efficient use of switchs processing capabilities

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Content and Multilayer Switches

• Layer 3 switch (routing switch)
• Interprets Layer 3 data
• Combines functions of switch and router
• Layer 4 switch
• Interprets Layer 4 data
• Content switch (application switch)
• Interprets Layer 4 through Layer 7 data

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Content and Multilayer Switches

• Advantages
• Advanced filtering
• Security functions
• Disadvantage no agreed upon standards
• Higher-layer switches
• Can cost up to 3 times that of Layer 2 switches
• Only used in backbone

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Routers

• Multiport connectivity device
• Directs data between network segments
• Connects LANs and WANs of different transmission
  speeds, media, and/or protocols
• Creates more latency than switches and/or
  bridges
• Traditional stand-alone LAN routers are being
  replaced by Layer 3 switches
• New specialized applications
• Linking large Internet nodes
• Completing digitized telephone calls

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Router Functions

• Path Determination select shortest or fastest
  path between two networks/subnets
• Static routing -- administrator configures
  specific paths
• Dynamic routing -- router configured with routing
  protocolsto calculate best path
• Broadcast containment routers never forward
  broadcasts
• Security can use IP addresses and/or port
  numbers to filter traffic

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Router Functions