I watched the “Arista Networks 7500 Series Architecture” video again last night. I’ve embedded it below.
I think that was at least the third time I’ve seen that video. Even if you’re not a networking nerd, I suggest that you watch it at least once.
Most of the video is about packet buffers. Specifically, it’s about big buffers vs small buffers in switches. Switches have packet buffers to sustain bursts. If a switch’s buffers fill up, it’ll start dropping packets. There’s nothing else it can do.
Dropped packets are a scenario we can tolerate. Protocols like TCP have mechanisms to detect and work around dropped packets. An application running on top of TCP doesn’t really see this dropping and retransmission happen. All it sees is network I/O getting slower. Back pressure.
There’s an important slide that comes up at around 20:00. It’s about the distribution of …[Read more]