1. COMMON LAYER 2
DEVICES AND
FUNCTIONALITIES

2. Introduction 7 6 5 4 3 2 1 Routers, PAD’s, X.25 switches
Bridges, LAN switches, ATM switches and terminal servers
Transceivers, repeaters, hubs, FDDI concentrators, MSAU’s, modems, terminal adapters, DSU’s, CSU’s, MUX and NIC’s 3 2 1

3. 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. 7 6 5 4 3 2 1

4. Bridges

5. 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. 7 6 5 4 3 2 1

6. Switches