Networking

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Networking

• Chapter 12

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Areas of Discussion

• OSI Model
• IP Addressing
• Local Area Networks
• Wide Area Networks
• Remote Access
• Network Management
• Voice and Data Convergence
• Additional Resources

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OSI Model

• Application Layer
• Presentation Layer
• Session Layer
• Transport Layer
• Network Layer
• Data Link (MAC) Layer
• Physical Layer

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Internet Protocol Suite

• What is a protocol?
• Set of rules and standards that ease the
  interconnectivity of devices of different
  platforms and from different vendors.
• TCP/IP Transmission control protocol/Internet
  protocol
• Application Layer (session, presentation, and
  application)
• Transport Layer (transport)
• Inter-network (network)
• Link (physical and data link)

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IP Addressing

• IP addressing 32-bit string
• 4 eight-bit numbers
• Each eight-bit number is an octet
• Can be value of 0 to 255
• Network address and host address
• Subnet masks
• Class A 1-126
• Class B 128-191
• Class C 192-223

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A Shortage of Addresses

• American Registry for Internet Numbers (ARIN)
  1997 registers and administers IP numbers for
  North America.
• Other global regions are managed by RIPE NCC,
  LACNIC, and APNIC.
• Running out of numbers
• Solutions
• Network Address Translation
• IPv6

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• Network Address Translation
• Translates your internal network addresses into
  the public address assigned to your Internet
  connection.
• However, there are agreed upon standards for
  private internal networks
• 10.0.0.0 10.255.255.255 (1 class A range)
• 172.16.0.0. 172.31.255.255 (16 class B
  ranges)
• 192.168.0.0. 192.168.255.255 (256 class C
  ranges)

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• IPv6 IP next generation or IPng
• IPv4 allows for approximately 4 billion addresses
• IPv6 allows for 340 undicillion (340 followed by
  36 zeroes) addresses.
• Changes from a 32-bit address to a 128-bit address

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• DNS Domain Name Server translates
  alphanumeric names to IP addresses
• A DNS allows you to name your servers and devices
  and translates those names to IP addresses
• The DNS environment of the Internet allows you
  and your users to use meaningful names (like
  browser URLs), as opposed to IP addresses.

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• DHCP
• Dynamic Host Configuration Protocol (DHCP)
  automatically assigns IP addresses.
• Some devices need to have static addresses such
  as printers, which recognize MAC addresses
• Greatly eases the burden of IP administration

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Local Area Networks

• Network that connects the devices in one
  geographic location.
• As a general rule, a LANs boundary is
  telecommunication facilities and a router.
• LAN is dependent on needs, plans for future
  growth, and changes of use.
• Ethernet is the de facto standard.

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• LAN Design
• Goals of a good LAN design
• Maximizing the efficiency of network traffic
• Reliability
• Manageability growth and traffic patterns,
  bottlenecks, and problem areas
• Flexibility
• Location of devices
• Traffic volume

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• The Core Network
• Single device or multiple devices
• Features of Switches
• Number and types of connections required
• Total throughput
• Redundancies
• Forwarding methods store and forward,
  cut-through forward, fragment free
• Layer 2 and Layer 3
• Chassis or Stackable

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• Wireless LANs
• WiFi (wireless fidelity) up to 300 feet
• Eliminates need for running cabling
• Wireless security
• Wired equivalent privacy (WEP) the first method
  developed for securing wireless LANs. Key
  (either 40 or 128 bits in length). Easy to
  hack.
• WiFi protected access (WPA) Temporal Key
  Integrity Protocol (TKIP), developed overcome
  weakness of WEP. Changes the key with each data
  frame. Built-in authentication

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• Wireless security
• Hidden SSID Service Set Identifier
  Environment with multiple wireless networks, SSID
  identifies which network is which.
• MAC Filtering allow only predetermined devices
  to connect to it by specifying the MAC address of
  authorized devices.
• Internet Access only connects to Internet only.
  Must use other remote access solutions to
  connect to private internet.

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• Bluetooth shorter range of typically 30 feet
• Is considered a wireless alternative for USB-type
  connections while WiFi is considered a wireless
  alternative for Ethernet connections.

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Wide Area Networks

• Connects the remote locations via
  telecommunication facilities (T-1 lines, ISDN,
  etc.)
• Span large distances
• Design based upon geography, traffic flow, and
  volumes.

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Difference between LANs and WANs

• Majority of LAN costs are up-front capital
  expenditures of cable installation and hardware.
• Majority of WAN costs are recurring operating
  costs of lines.

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• Considerations for a WAN
• Need for high-speed transmissions
• Need for 24/7 operations
• User needs locations, travel
• Backup/fail-over capabilities and facilities
  most critical connections need to be most
  reliable
• Installation delays the more sophisticated the
  line, the more time your telecommunications
  vendor will need to install it.

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• Routers key devices for WANs
• Forwards data to another network
• Occurs at Layer 3 of OSI model
• Acts as transfer point between two networks to
  pass data packets between them
• Routing table is used by the routers to determine
  the best path to use for each data packet

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• Key WAN Technologies
• Connectivity Options
• Point-to-point circuits leased, dedicated, and
  private lines
• T-1 line 24 channels of 64 Kbps, for an
  aggregate throughput of 1.544 Mbps
• T-3 line (often referred to as DS3)
  transmission speeds of 44,736 Mbps, via 672
  circuits, each of 64 Kbps transmission
• Fractional T-1 or fractional T-3. See page 329.

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• continued
• Connectivity Options
• Dial-up
• Plain Old Telephone System (POTS) line
• Based on analog technology
• 56 Kbps

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• continued
• ISDN Integrated Services Digital Network
• Digital transmission over standard copper
  telephone wire
• Basics Rate Interface (BRI) homes and small
  businesses
• Two 64Kbps B channels and one 16 Kbps D channel
• B channel carries the data and D channel carries
  signaling
• Throughput total of 128 Kbps
• Primary Rate Interface (PRI) larger sites
• 23 B channels and one 64 Kbps D channel
• Throughput total of 1.4 Mbps
• Dial their calls similar to the way POTS lines do
• Often used for back up of T1-lines

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• continued
• Broadband (cable modems and DSL)
• past definition connection type that can carry
  more than one signal at a time
• Today high-speed connection to the Internet
• Offer faster downstream rate than upstream rate
• Always on
• DSL digital subscriber line. Phone company
  offering to bring high-speed Internet to homes
  and small businesses over standard copper phone
  lines.
• Always on
• High-speed downstream
• Must be within few miles of telephone company
  central office

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• Continued
• Broadband (cable modems and DSL)
• Cable TV companies deliver high-speed Internet
  access.
• Speed is often 384 Kbps upstream and 2 Mbps
  downstream

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• Continued
• Packet switching (ATM and frame relay)
• Breaks up data transmission into small packets
• Asynchronous Transfer Mode (ATM) and Frame Relay
  
• Frame relay speeds between 56 Kbps and 45 Mbps
• ATM speeds between 25 to 622 Mbps
• Used for delay-sensitive applications like voice
  and video plus data
• Frame relay and ATM provided by telecom carriers
• ATM Sustained Information Rate (SIR)
• Frame Relay Committed Information Rate (CIR)
• Data below this level will be guaranteed
  delivery if dropped, will be retransmitted

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• Continued
• High-speed Internet
• Connection to the Internet
• Point-to-point circuits
• Broadband
• Fees for line to your office
• Fees for Internet access
• Virtual Private Networks (VPNs) using security
  and tunneling techniques, establish a VPN via the
  Internet to connect sites
• Split tunneling remote offices connect to the
  Internet and establish a VPN back to headquarters
  while local Internet access goes directly to
  Internet

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Remote Access

• Companies are now available 24/7
• The Choices
• Your connection path
• Internet access
• Direct access
• Handheld device
• What you Connect to
• Web-based applications
• Remote control
• Remote node
• Handheld device applications
• Replication (synchronization)

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• Questions
• What are the needs of your customers?
• Based upon the answer, select your options

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• The Connection Path
• Three options for connection
• Through the Internet
• Through a direct connection
• Through the air waves using a handheld device

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• Continued
• What You Connect To
• Web-based applications
• Microsofts outlook Web Access (OWA) or iNotes
  from Lotus Notes
• Remote control
• Establish a connection
• Establish a remote control session
• Centralized Remote control
• Terminal servers
• Remote node
• Handheld device applications
• Replication (Synchronization) use applications
  and items are saved, when connected, can transmit
  to main headquarters.

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• Advantages
• reduces time needed for connection
• Users can work regardless of whether or not they
  have connectivity
• Disadvantages
• Applications must be same for best results XP
  vs. Vista

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• Continued
• Security for Remote Access
• Firewalls
• VPNs used for connections that come via the
  Internet to encrypt the data.
• Point-to-point Tunneling Protocol losing
  popularity
• L2TP combines two secure communication
  protocols Cisco Systems Layer Two Forwarding
  (L2F) and Microsofts PPTP.
• IPSec algorithms and a public key to encrypt
  the data at Layer 3. Also uses Internet Key
  Exchange (IKE) protocol to authenticate the two
  end nodes in the communication session.
• Two modes transport mode, only the data portion
  of the packet is encrypted, but not the header
• In tunnel mode both the header and the data are
  encrypted

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• Continued
• Radius Remote Authentication Dial-In User
  Service (RADIUS)
• User attempts to dial in to a remove access
  device, device authenticates, user is routed to
  network otherwise disconnected.

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Network Management

• Finding problems
• Vendors generally offer management functionality
  that allows you to collect data about the network
• Can purchase management tools
• Management Tools
• SNMP Simple Network Management Protocol works
  by sending messaged, called protocol data units
  (PDUs), to various devices on the network.
  SNMP-compliant devices, called agents, store data
  about themselves in Management Information Bases
  (MIBs) and return this data to the SNMP
  requesters.

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• Management Tools
• RMON remote monitoring takes SNMP to the next
  level. While SNMP manages devices, RMON can
  monitor the actual network traffic, collect
  statistics, and record history.

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• Quality of Service (QoS) and Bandwidth Management
• QoS allow you to prioritize types of traffic or
  applications
• Gives priority to time-sensitive applications
• Built into a variety of hardware and software
  products such as Cisco and Microsoft

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• Continued
• You can
• Classify different types of traffic (video,
  audio, data)
• Prioritize mission-critical and time-sensitive
  traffic
• Load balance across multiple resources for
  redundancy and performance.

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Voice and Data Convergence

• Voice Over Internet Protocol (VoIP)
• Pros
• Administer and manage one infrastructure
• Handsets in any location
• Not really occurring any additional costs
• Telecommunters use laptops for telephone service
• Data integration

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• Cons
• VoIP relatively new technology
• Audio-quality problems
• Interruption of service with network
• Software upgrades for handheld devices
• Service in the event of power outage
• Latency
• Voice people need to learn about network

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Summary Slide

• OSI Model
• Internet Protocol Suite
• IP Addressing
• Local Area Networks
• Wide Area Networks
• Remote Access
• Network Management
• Voice and Data Convergence