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The following will be discussed in this chapter: Network congestion, bridges, LAN Switch features, Switches supersede bridges, Ethernet switches and bridges, transmitting frames , MAC address table, learning addresses,. Inviting you to refer. | Ethernet Switch Network Congestion High-performance PCs More networked data Bandwidth-intensive applications Lesson Aim Bridges Operate at Layer 2 of the OSI model Forward, filter, or flood frames Have few ports Are slow LAN Switch High port density Large frame buffers Mixture of port speeds Fast internal switching Switching modes: Cut-through Store-and-forward Fragment-free Lesson Aim LAN Switch Features Lesson Aim Switches Supersede Bridges Operate at Layer 2 of the OSI model Forward, filter, or flood frames Have many ports Are fast Ethernet Switches and Bridges Address learning Forward/filter decision Loop avoidance Transmitting Frames Cut-Through Switch checks destination address and immediately begins forwarding frame. Fragment-Free Switch checks the first 64 bytes, then immediately begins forwarding frame. Store and Forward Complete frame is received and checked before forwarding. MAC Address Table . | Ethernet Switch Network Congestion High-performance PCs More networked data Bandwidth-intensive applications Lesson Aim Bridges Operate at Layer 2 of the OSI model Forward, filter, or flood frames Have few ports Are slow LAN Switch High port density Large frame buffers Mixture of port speeds Fast internal switching Switching modes: Cut-through Store-and-forward Fragment-free Lesson Aim LAN Switch Features Lesson Aim Switches Supersede Bridges Operate at Layer 2 of the OSI model Forward, filter, or flood frames Have many ports Are fast Ethernet Switches and Bridges Address learning Forward/filter decision Loop avoidance Transmitting Frames Cut-Through Switch checks destination address and immediately begins forwarding frame. Fragment-Free Switch checks the first 64 bytes, then immediately begins forwarding frame. Store and Forward Complete frame is received and checked before forwarding. MAC Address Table Initial MAC address table is empty. Learning Addresses Station A sends a frame to station C. Switch caches the MAC address of station A to port E0 by learning the source address of data frames. The frame from station A to station C is flooded out to all ports except port E0 (unknown unicasts are flooded). Learning Addresses (Cont.) Station D sends a frame to station C. Switch caches the MAC address of station D to port E3 by learning the source address of data frames. The frame from station D to station C is flooded out to all ports except port E3 (unknown unicasts are flooded). Forward Frames Station A sends a frame to station C. Destination is known; frame is not flooded. Filtering Frames Station A sends a frame to station B. The switch has the address for station B in the MAC address table. Broadcast and Multicast Frames Station D sends a broadcast or multicast frame. Broadcast and multicast frames are flooded to all ports other than the originating port. Symmetric switching A symmetric
