Bufferbloat
When oversized network buffers turn milliseconds into seconds — the reason your video call stutters the moment someone uploads a file.
Memory got cheap, so router vendors gave their devices generous buffers. The problem: TCP detects congestion through packet loss. A large buffer drops nothing, it queues — so TCP keeps speeding up until the queue is seconds deep. Every other flow waits in that same queue.
Jim Gettys coined the term in 2010. The cure is active queue management: CoDel and fq_codel drop packets early to keep the queue short. In OpenWrt since 2012 and the Linux kernel since 3.5.