Second Generation switches Bus LC LC LC Most of the processing is now done in the line cards Route table look-up etc Line cards buffer the packets Line card send packets to proper output port Advantages: CPU and main Memory are no longer the bottleneck Disadvantage: Performance limited by bus speeds Bus Bw must be n times LC speed(N ports Example: cisco 7500 series routerSecond Generation switches Computer LC LC LC LC Bus • Most of the processing is now done in the line cards – Route table look-up, etc. – Line cards buff er the packets – Line card send packets to proper output port • Advantages: CPU and main Memory are no longer the bottleneck • Disadvantage: Performance limited by bus speeds – Bus BW must be N times LC speed (N ports) • Example: CISCO 7500 series router Eytan Modiano Slide 4