"But this shift is not without its problems. Unlike e-mail and static Web pages, which can handle network hiccups, voice and video deteriorate under transmission delays as short as a few milliseconds. And therein lies the problem with traditional IP packet routers: They can’t guarantee that a YouTube clip will stream smoothly to a user’s computer. They treat the video packets as loose data entities when they ought to treat them as flows.
"Consider a conventional router receiving two packets that are part of the same video. The router looks at the first packet’s destination address and consults a routing table. It then holds the packet in a queue until it can be dispatched. When the router receives the second packet, it repeats those same steps, not ”remembering” that it has just processed an earlier piece of the same video. The addition of these small tasks may not look like much, but they can quickly add up, making networks more costly and less flexible.
"At this point you might be asking yourself, ”But what’s the problem, really, if I use things like Skype and YouTube without a hitch?” In fact, you enjoy those services only because the Internet has been grossly overprovisioned."
