COMMON LAYER 2

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COMMON LAYER 2 DEVICES AND FUNCTIONALITIES
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Introduction
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• Routers, PADs, X.25 switches
• Bridges, LAN switches, ATM switches and terminal
  servers
• Transceivers, repeaters, hubs, FDDI
  concentrators, MSAUs, modems, terminal adapters,
  DSUs, CSUs, MUX and NICs

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Bridges

• Bridges analyze incoming frames, make decisions
  based on the information and forward the frames
  to the destination
• Bridges operate at the Data Link layer, allowing
  them to rapidly forward traffic representing any
  network-layer protocol
• Bridges control data flow, handle transmission
  errors, provide physical addressing and manage
  access to the physical medium
• Bridges are capable of filtering frames based on
  any Layer 2 fields
• Bridges can be used to connect dissimilar
  networks, allowing communication between them.

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Bridges
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LAN Switches

• Switches provide dedicated bandwidth and high
  packet throughput to users and servers at low
  cost
• Switches are designed to work with the existing
  cable infrastructures so they can be installed
  with minimal disruption to existing networks
• Switches may replace shared hubs
• LAN switches are a type of fast multi-port bridge
  designed to increase the performance of the LAN
  by separating collision domains and selectively
  forwarding traffic to the appropriate segments
• LAN switches improve the performance of LANs as
  they create isolated collision domains
• LAN switches have the benefits of increased
  capacity, segmentation, parallel conversations
  and connectivity for LANs.

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Switches