Local Area Network

1
Local Area Network
2
Objectives

• Understand how access methods, logical
  topologies, and physical topologies combine to
  form alternative network architectures.
• Understand the similarities and differences
  between and the advantages and disadvantages of
  current network architectures.

3
LAN Architects

• Access Methods
• CSMA/CD and Token-Ring
• Logical Topology
• Sequential and Broadcast
• Physical Topology
• Bus, Ring and Star

4
Topologies
5
Ethernet

• Access Methodology
• Logical Topology
• Physical Topology

• ?
• ?
• ?

6
Ethernet

• Access Methodology
• Logical Topology
• Physical Topology

• CSMA/CD
• Broadcast
• Traditionally Bus - most often used Star

7
Token Ring

• Access Methodology
• Logical Topology
• Physical Topology

• ?
• ?
• ?

8
Token Ring

• Access Methodology
• Logical Topology
• Physical Topology

• Token Passing
• Sequential
• Traditionally Ring - most often used Ring

9
FDDI

• Access Methodology
• Logical Topology
• Physical Topology

• ?
• ?
• ?

10
FDDI

• Access Methodology
• Logical Topology
• Physical Topology

• Token Passing
• Sequential
• Dual counter-rotating rings

11
Switches
12
Nice to knows

• An octet is eight bits of data potentially
  representing digitized voice, video, images, or
  other digital information.
• A byte is eight bits representing a particular
  character or number.

13
DuplexingHalf Full

• All systems must listen prior to sending
• Can only send or receive at a given time
• 30-40 utilization on Ethernet
• Doesnt require any special hardware or software

• Ability to send and receive at the same time.
• Collisions not possible
• 95 utilization on Ethernet
• Requires a Switch and Multi-threading OS

14
Greggs Rule 2

• 80 of all network errors occur at the physical
  layer