FDDI Fiber Distributed Data Interface

1
FDDI(Fiber Distributed Data Interface)

• Uses a dual fiber-optic ring to transmit data at
  speeds of 100 Mbps
• Network backbone 80s
• Fiber more reliable and secure over copper
• More expensive
• Ring technology like TR, but has two rings w/
  one as a backup

FIGURE 7-10 FDDI network
2
X.25 and Frame Relay

• X.25
• Analog packet switched LAN technology optimized
  for long-distance data transmission (originally
  mainframe connectivity)
• Supports 56 Kbps 1970s
• Frame Relay
• Updated digital version of X.25 that relies on
  packet switching

FIGURE 7-11 WAN using Frame Relay
3
X.25 and Frame Relay

• FR supports up to 45 Mbps mid-80s technology
• PVCs (private virtual circuits)
• Point-to-point communication over which data may
  follow any number of different paths
• Not dedicated (like T-carrier)
• X.25, Frame Relay, and some forms of ATM use PVCs
• Committed information rate (CIR)
• Guaranteed minimum amount of bandwidth selected
  when leasing a Frame Relay circuit bursting
  ability
• Cheaper only buy what you need oversubscription

4
ATM(Asynchronous Transfer Mode)

• WAN transmission that relies on a fixed packet
  size to achieve data transfer rates from 25 to
  622 Mbps popular telco backbone solution
• Cell
• The fixed packet in ATM 48 bytes plus a 5-byte
  header
• Predictable traffic patterns are attainable and
  better control over bandwidth usage
• QoS

5
ATM(Asynchronous Transfer Mode)

• SVCs (switched virtual circuits)
• Logical point-to-point connections that rely on
  ATM switches to determine the optimal path
  between sender and receiver
• Created for the duration of the transfer
• ATM is good for time sensitive data (video,
  audio)
• More expensive and hard to find technical base
• Competition is with fast Ethernet
• JC OC-3 155 Mbps

6
SONET(Synchronous Optical Network)

• Can provide data transfer rates from 64 Kbps to
  2.4 Gbps using the same TDM technique used by
  T-carriers
• Developed in the 80s and popular backbone choice
• Use of a dual-ring (like FDDI) and is
  self-healing
• Company can purchase part or the entire ring from
  the telco

FIGURE 7-12 SONET ring
7
SONET(Synchronous Optical Network)
Data rate based on OC (Optical Carrier) level
TABLE 7-3 SONET OC levels
8
WAN Implementation

• Speed

TABLE 7-4 Comparison of WAN technology
transmission speeds
9
WAN Implementation

• Reliability of WAN technologies can be
• Not very reliable, suited for individual or
  unimportant transmissionsPSTN dial-up
• Sufficiently reliable, suited for day-to-day
  transmissionISDN, T1, fractional T1, T3, xDSL,
  cable, X.25, and Frame Relay
• Very reliable, suited to mission-critical
  applicationsFDDI, ATM, and SONET

10
Security

• Issues to consider with security
• WAN security depends in part on the encryption
  measures each carrier provides for its lines
• Enforce password-based authorization for LAN and
  WAN access
• Develop, publish, and enforce a security policy
  for users in an organization
• Maintain restricted access to network equipment
  rooms and data centers

11
Virtual Private Networks (VPNs)

• Long-distance networks logically defined over
  public transmission systems that serve all of an
  organizations users, but isolate that traffic
  from other users on the same public lines VERSUS
  VLANs

FIGURE 7-13 Example of a VPN
12
Establishing Remote Connectivity

• Remote access methods
• Direct dial to the LAN
• Remote access server (RAS)
• Provides central access point for multiple users
  to dial into a LAN or WAN
• Remote node
• Computer dialed into a LANs remote access server

13
Establishing Remote Connectivity

• Remote access methods (cont.)
• Direct dial to a workstation
• Remote control
• Sofware that provides this functionality?
• Internet/Web interface
• Browser access vs. VPN
• Remote Access Service (RAS)
• Simple dial-in server

14
Dial-Up Networking

• Process of dialing into a LANs access server or
  to an ISP
• To install Dial-Up Networking and bind it to your
  existing protocols and adapters
• Insert the Windows 95 CD-ROM
• Click Start, point to Settings, then click
  Control Panel
• Double-click Add/Remove Programs icon
• Click Windows Setup tab

15
Dial-Up Networking

• Installing and binding Dial-Up Networking (cont.)
• In the Components list, click Communications,
  then click Details
• Click the box next to Dial-Up Networking
• Click OK
• Click Yes to restart your computer

16
Creating a Dial-Up Networking Profile

• On Windows 95 desktop, double-click My Computer
  icon
• Double-click Dial-Up Networking icon
• Double-click Make New Connection icon

FIGURE 7-14 Creating a Dial-Up Networking
connection
17
Creating a Dial-Up Networking Profile

• Enter the required information
• Once modem is selected, click Next
• Type the number of the system being dialed into
• Click Next
• Click Finish

18
Configuring a Dial-Up Networking Profile

• In Dial-Up Networking window, right-click desired
  connection
• Click Properties
• Click Server Types
• Select the type of server specified by your ISP

19
Configuring a Dial-Up Networking Profile

• Select any of the following optional parameters
  Log On to Network, Enable Software Compression,
  or Require Encrypted Password
• Select protocol from Allowed Network Protocols
• Click TCP/IP Settings
• Enter the parameters provided by your ISP
  (usually the Server Assigned IP Address can be
  left, but will probably be necessary to enter at
  least one specific name server address

20
Configuring a Dial-Up Networking Profile

• Choose Use IP Header Compression or Use Default
  Gateway on Remote Network depending ISPs
  directions
• Click OK
• Click OK again
• Test the connection to the remote server

21
SLIP and PPP

• Dial-up network protocols
• Protocols that allow a workstation to connect to
  a server via a serial port (modem)
• Such protocols are needed to transport network
  layer traffic over serial interfaces (which
  belong to the data link layer)
• SLIP (serial line interface protocol)
• PPP (point to point protocol)
• Both encapsulate higher-layer networking
  protocols in their lower layer data frames

22
SLIP and PPP

• Asynchronous communication
• No timing scheme between sender and receiver
• Data transfer occurs at random starts and stops
• Transfer is independent
• Use of start and stop bit interrupt model
• Synchronous communication
• Timing scheme is used for communication
• Clock is maintained for all nodes on the network
  through the use of a window of transfer and
  receive
• No stop / start bit Client / server respond to
  each other

23
SLIP and PPP

• Serial Line Internet Protocol (SLIP)
• Communications protocol enabling a workstation to
  connect to a server using a serial connection
• Supports only asynchronous transmission
• IP only
• Point-to-Point Protocol
• Communications protocol enabling a workstation to
  connect to a server using a serial connection
• Supports both asynchronous and synchronous
  transmission
• Many different protocols

24
Chapter Summary

• WANs are distinguished from LANs by the fact that
  the former networks traverse a wider geographical
  area
• One WAN transmission method, PSTN, relies on the
  network of telephone lines that typically service
  homes
• Another WAN transmission method, ISDN, is an
  international standard established by the ITU for
  transmitting data over digital lines

25
Chapter Summary

• Two types of ISDN connections are commonly used
  in North America BRI and PRI
• Another WAN transmission method is digital
  subscriber line (DSL)
• Cable is another option for WAN transmission
• Other WAN links depend on leased lines
• T-carrier transmission uses a technology called
  multiplexing to divide a single channel into
  multiple channels for carrying voice, data,
  video, or other signals

26
Chapter Summary

• FDDI is a networking standard originally
  developed by ANSI in the 1980s and later refined
  by ISO
• X.25 is an analog packet switched technology
  optimized for long-distance data transmission
• Frame Relay is an updated, digital version of
  X.25
• ATM relies on a fixed packet size to achieve data
  transfer rates ranging from 25 to 622 Mbps
• span, growth, and cost

27
Chapter Summary

• SONET can provide data transfer rates from 64
  Kbps to 2.4 Gbps using the same TDM technique
  employed by T-carriers
• When installing or upgrading a WAN, consider its
  ability to integrate with your present equipment,
  transmission speed required, security needed,
  geographical distance the WAN must
• VPNs represent one way to construct a WAN from
  existing public transmission systems

28
Chapter Summary

• Three ways remote users connect to LANs direct
  dial to the LAN, direct dial to a workstation,
  and an Internet connection with a Web interface
• SLIP and PPP are communications protocols
  enabling a workstation to connect to a server
  using a serial connection