70-293: MCSE Guide to Planning a Microsoft Windows Server 2003 Network, Enhanced Chapter 3: Planning Network Data Flow

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70-293 MCSE Guide to Planning a Microsoft
Windows Server 2003 Network, Enhanced Chapter
3 Planning Network Data Flow
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Objectives

• Describe the three types of network traffic
• Understand unique characteristics of Ethernet
• Use physical components of a network to control
  data flow
• Monitor network performance
• Optimize network settings
• Use network troubleshooting utilities

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Types of Network Traffic

• Network traffic is defined as packets of data
  sent on the network
• Three types of IPv4 packets
• Unicast
• Broadcast
• Multicast

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Unicast Packets

• A unicast packet is addressed to a single
  computer
• The destination IP address in a unicast packet is
  a Class A, B, or C IP address
• This type of traffic can communicate on the
  Internet and perform file and printer sharing in
  the network

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Broadcast Packets

• Local broadcasts are used by applications to
  announce status and ensure that all interested
  hosts are informed
• Broadcast packets are inefficient because they
  are processed by all hosts on a subnet
• On a busy host this may reduce performance levels

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Activity 3-1 Analyzing a Broadcast

• The purpose of this activity is to view the
  contents of a broadcast packet

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Multicast Packets

• Multicast packets are addressed to a group of
  computers using a Class D IP address
• Multicast packets are an improvement over
  broadcast packets because multicast packets are
  processed by all hosts up to only the Internet
  layer rather than up to the Application layer
• This reduces the processing load on busy hosts

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Ethernet

• Ethernet is the most common network technology
  used for LAN connectivity
• Popularity of Ethernet is due to its high
  performance and low price
• Three important Ethernet concepts are
• Collisions
• Collision domains
• Transmission modes

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Collisions

• If two computers happen to transmit information
  on the network at the same time, then a collision
  results
• Ethernet uses Carrier Sense Multiple
  Access/Collision Detection (CSMA/CD) as the
  access method to determine which computer is
  allowed to send data on the network and when
• When a collision occurs, the two computers that
  are transmitting data stop and wait for a random
  period of time before resending

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Transmission Modes

• A transmission mode is how data is sent on the
  network
• Ethernet networks are capable of transmitting at
• Half-duplex mode
• can send data or receive data, but cannot do both
  at the same time
• Full-duplex mode
• can transmit and receive information at the same
  time

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Activity 3-2 Viewing Ethernet Settings

• The purpose of this activity is to view various
  Ethernet settings

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Media

• Media is the physical component that connects all
  of the devices together
• The most common media types used in computer
  networks are
• Twisted-pair
• Fiber optic
• Coaxial

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Media (continued)

• Twisted-pair cabling is the most common type of
  cabling used in computer networks
• On an Ethernet network, it can carry data at up
  to 1 Gbps at a maximum distance of 100 meters
  over a single segment

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Media (continued)

• Fiber-optic cabling is used for network backbones
  where twisted-pair cabling cannot transmit the
  distance needed
• On an Ethernet network, it can carry data at up
  to 10 Gbps for a 2 kilometers
• Two fibers are required for each connection one
  for sending data, the other for receiving

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Media (continued)

• Coaxial cabling was common on older Ethernet
  networks, but has been removed from most networks
  
• Coaxial cable cannot transmit in full-duplex mode
• Coaxial cabling is now expensive compared to
  twisted-pair cabling

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Media (continued)

• Wireless connectivity is not part of the Ethernet
  standard very popular now
• A major cost savings in wireless implementations
  is the lack of cabling installation
• Security is a concern with wireless connectivity

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Hubs

• A hub acts as a central connection point on a
  network that allows multiple computers to
  communicate with each other
• A hub can also be used to extend the network for
  greater distance
• A hub operates at the Physical layer of the OSI
  model and is responsible for media
  characteristics and electrical signaling

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Latency

• When a signal passes through a hub, it takes a
  small amount of time for the signal to be
  regenerated
• The delay between receiving the signal and
  sending it out again is called latency

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Latency (continued)

• When many hubs are linked, a high level of
  latency is introduced and the carrier sense
  portion of CSMA/CD becomes unreliable
• When the latency is high, the number of
  collisions increases because a computer at one
  end of the collision domain can begin sending a
  packet while another computer at the other end is
  sending a packet at the same time

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Switches

• A switch divides network traffic based on MAC
  addresses
• Switches can operate at full-duplex
• Switches operate at the Data Link layer of the
  OSI model
• Switches can perform tasks that deal with full
  packets of data and MAC addresses

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Switches (continued)

• A switch has several benefits over a hub
• Each port on a switch is a separate collision
  domain allowing the division of large networks
  and a reduction in the number of collisions
• A switch can direct traffic only to the port to
  which the destination computer is attached, which
  reduces overall levels of network traffic
• Switches can connect dissimilar network
  architectures, such as Ethernet and wireless

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Switches (continued)
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Switches (continued)
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Routers

• Routers are used to move traffic between networks
• A router operates at the Network layer of the OSI
  model which allows the control of network traffic
  based on logical IP addresses
• Routers maintain a list of IP networks called a
  routing table
• Routers are more scalable than switches
• Routers can control traffic for hundreds of
  thousands of computers, whereas switches normally
  can track thousands of computers

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Monitoring and Optimizing Network Performance

• A bottleneck is any point in the communication
  process that cannot perform at the same level as
  other components
• Bottlenecks can occur in the physical network or
  in server components
• Network performance is limited by bottlenecks

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Network Performance Problems and Solutions

• The tools used to monitor network performance
  include
• Protocol analyzers
• Cable testers
• Task Manager
• Performance snap-in

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Protocol Analyzers

• Protocol analyzers can capture network traffic
  and monitor network performance
• A protocol analyzer can be used to look at each
  packet in the communication process to see where
  the problem lies
• Network Monitor is a limited protocol analyzer
  included with Windows Server 2003
• Ethereal is an alternative packet analyzer that
  is very popular and free

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Cable Testers

• A cable tester checks the ability of a cable to
  carry the electrical signals properly that are
  sent by the computers
• Each cable tester can verify the proper
  installation of only certain types of cabling

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Task Manager

• Task Manager is a simple tool that can be used
  to
• Check memory
• Processor
• Network utilization

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Performance Snap-in

• The Performance snap-in located in Administrative
  Tools can be used to generate graphs and log many
  Windows Server 2003 performance indicators
• The graphs generated by the Performance snap-in
  can capture short- and medium-term information

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Activity 3-3 Monitoring Network Performance

• The purpose of this activity is to view network
  utilization using Network Monitor, Task Manager,
  and the Performance snap-in

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Optimizing Network Settings

• Network performance gains can be made by
  modifying the network configuration of the servers

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Utilizing the Binding Process

• Binding is the process in which a network
  protocol is configured to use a network adapter
• When a protocol is added to a network connection,
  it is bound to the network adapter and the
  services that are part of that connection
• Windows Server 2003 allows you to optimize your
  network connectivity by
• Adjusting the order in which protocols are used
• Defining the priority of network services

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Minimizing Network Protocols

• If a protocol is required to support older
  clients, explore centralizing all services using
  that protocol on a single server
• This reduces the service advertisements produced
  by other servers and reduces the processing
  required on other servers

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Implementing the Maximum Transmission Unit (MTU)
Setting

• The Maximum Transmission Unit (MTU) setting sets
  the maximum packet size that TCP/IP will try to
  negotiate when creating a TCP connection
• The default MTU setting is 1,500 bytes on an
  Ethernet network

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Troubleshooting Utilities

• Windows Server 2003 has a wide variety of
  utilities that can be used to troubleshoot
  network problems
• It is important to understand what each tool does
  and when it is appropriate to use

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Ping

• Ping confirms that a host is active at an IP
  address
• Ping can be used to test for DNS resolution
  problems
• When you ping a host, the Ping utility indicates
  how long it took for the remote host to respond

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Tracert

• The Tracert utility is used to view the routers
  that a packet passes through between the local
  host and a remote host
• When using the Tracert utility to troubleshoot
  Internet connectivity, look for the router that
  stops responding this one is preventing users
  from accessing a particular server

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Pathping

• Pathping can be used to view the routers used to
  move a packet from the local host to a remote
  host
• However, the Pathping utility sends 100 packets
  to each router in the path to provide a more
  accurate measure of response times

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Activity 3-4 Testing for Network Congestion with
Pathping

• The purpose of this activity is to test to see if
  the network is congested using the pathping
  command

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Nbtstat

• Nbtstat is used to view NetBIOS over TCP/IP
  statistics
• It can view the list of NetBIOS services
  available on the local host or remote hosts, and
  it can view the local NetBIOS name cache

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Netstat

• Netstat displays TCP connection information and
  various IP statistics, such as the number of UDP
  and TCP packets and the IP routing table
• Viewing TCP connections is useful for finding
  rogue services

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Network Diagnostics

• Network Diagnostics can be used to view a variety
  of settings on your server
• It builds a list of information about your server
  and tests services such as DNS and WINS to ensure
  availability

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Activity 3-5 Viewing TCP Connections with Netstat

• The purpose of this activity is to view open
  connections and running services with the Netstat
  utility and view the current network
  configuration with Network Diagnostics

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Ipconfig

• The ipconfig command can be used to
• View IP configuration information
• Release and renew IP addresses that are obtained
  from a DHCP server
• Flush the DNS cache because Windows Server 2003
  caches all DNS lookups

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Netsh

• Netsh is a command-line utility that can be used
  to modify and view IP configuration information
• It is useful for remotely managing IP
  configuration when Terminal Services is
  unavailable and via scripts

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Nslookup

• Nslookup is used to query DNS servers
• Can be configured to query any DNS server you
  want, making it easy to confirm the configuration
  of a particular DNS server that is having problems

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Summary

• Types of network traffic unicast, broadcast, and
  multicast
• Ethernet is the most common network architecture
• A collision domain is an area of a network where
  collisions occur
• Transmission modes are half-duplex and
  full-duplex
• Hubs operate at the Physical layer of the OSI
  model and send received data to all ports except
  the one from which it was received

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Summary (continued)

• Switches operate at the Data Link layer of the
  OSI model and control data flow based on MAC
  addresses
• Routers operate at the Network layer of the OSI
  model and control data flow based on IP addresses
• Tools used to identify bottlenecks include
  protocol analyzers, cable testers, Task Manager,
  and the Performance snap-in
• Can optimize network settings by adjusting
  bindings, minimizing number of protocols, and
  adjusting MTU

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Summary (continued)

• IP troubleshooting utilities
• Ping
• Tracert
• Pathping
• Nbtstat
• Netstat
• Network Diagnostics
• Ipconfig
• Netsh,
• Nslookup