Fundamentals of Computer Networking Hardware Architecture Lecture III IIITMK

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Fundamentals of Computer NetworkingHardwar
e ArchitectureLecture IIIIIITM-K
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NETWORK ARCHITECTURE
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Network Architecture

• Network architecture is the overall design of a
  network.
• The network design is divided into layers, each
  of which has a function separate from that of the
  other layers.
• Protocol stack The vertical (top to bottom)
  arrangement of the layers. Each layer is governed
  by its own set of protocols.

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Protocol Hierarchies

• Networking software is organized into layers to
  simplify design i.e., each layer providing
  certain kind of service to other layers but keep
  the implementation detail hidden.
• Peers in the same layer on different hosts
  communicate with each other using the same
  protocol in order to inter operate.
• Interface between adjacent layers define the
• Services the lower layer provides to the upper
  layer

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• Networks are categorized based on their three
  properties
• Protocol Topology Architecture

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NETWORK TOPOLOGIES

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LAN Hardware and Software

• Hardware
• Network interface card (NIC) Inserted into a
  computers expansion slot

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LAN Software

• Operating system that supports networking (Unix,
  Linux, Windows, Mac OS)
• Additional system software

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PEER-TO-PEER NETWORKS

• All computers on the network are treated as
  equal.
• There are no file servers.
• Users decide which files and peripherals to
  share.
• They arent suited for networks with many
  computers.
• They are easy to set up. Example Home networks

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CLIENT-SERVER NETWORKS
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CLIENT-SERVER NETWORKS

• Typical corporate networks are client-server.
• They use various topologies or physical layouts.
• The network requires file servers, networked
  computers (clients), and a network operating
  system (NOS).
• Clients send requests to servers for programs and
  data, and to access peripherals.

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LAN TOPOLOGIES

• The physical layout of a LAN is called its
  topology.
• Topologies resolve the problem of contention,
  which occurs when multiple users try to access
  the LAN at the same time.
• Collisions or corrupt data occur when different
  computers use the network at the same time

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BUS NETWORK TOPOLOGY
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RING NETWORK TOPOLOGY
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STAR NETWORK TOPOLOGY
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LAN PROTOCOLS

• LAN protocols are standards that govern the
  layers of the protocol stack.
• Lower-layer protocols deal with contention
  between computers.
• Lower-layer protocols
• Ethernet
• Local Talk
• Token ring

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• Higher-layer protocols handle the network
  functions.
• Higher-layer protocols
• AppleTalk
• IPX/SPX
• NetBeui
• TCP/IP

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WIDE AREA NETWORKS
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WIDE AREA NETWORKS

• WANs are similar to long-distance telephone
  systems.
• They have a local access number called a point of
  presence (POP).
• They contain long-distance trunk lines called
  backbones.

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POINT OF PRESENCE (POP)

• A point of presence is a WAN network connection
  point that enables customers to access the WAN by
  making a local telephone call.
• Media used to create a connection from an
  organization to a POP include
• 56 Kbps leased line
• ADSL
• ISDN
• T1 line
• Permanent virtual circuit (PVC)

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BACKBONES
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BACKBONES

• Backbones are high-capacity transmission lines
  that carry WAN traffic.
• They are regional, continental, or
  transcontinental.

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WAN ORGANIZATION

• INTERNET
• PUBLIC DATA NETWORK(PDN)
• PRIVATE DATA NETWORK

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WAN ORGANIZATION

• 1.INTERNET
• Backbone providers charge fees to Internet
  Service Providers (ISPs).
• ISPs sell subscriptions to users.
• Not secure
• Not ideal for businesses

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WAN ORGANIZATION

• 2.PUBLIC DATA NETWORK
• A for-profit data communications network
• Fees paid on a per-byte-transferred basis
• Good security
• High bandwidth

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WAN ORGANIZATION

• 3.PRIVATE DATA NETWORK
• Used by corporations, banks and governments
• Not open to the public
• Most secure type of WAN
• Virtual private network Lines are leased to a
  single company

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WAN PROTOCOLS

• X.25 Oldest packet switching protocol. It is
  used by automated teller machines and credit card
  authorization devices.
• Switched Multimegabit Data Service
  (SMDS)Designed for digital phone lines. Faster
  data transfer rates than X.25.
• Asynchronous Transfer Mode (ATM) Newer type of
  protocol. It is designed for digital lines.