Vint, Part V
LT: So until then, is throwing bandwidth at the Internet MCI's primary
means of making sure that there is enough capacity?
Cerf: Well, today we're over-engineering. That is the only way to make
sure that you get good QoS. At the same time, though, we are putting in
QoS hooks, called assured-access-rate mechanisms, into both the
domestic backbone and our international configuration.
We are doing that in part so our customers can tell us which traffic they
want to have priority and which traffic should take best-effort service.
Basically, the service is known as an assured access rate. It is not
dynamic. At subscription time, customers tell us what it is that they're
after in the way of an assured access rate and we will set the system up
for that. We mark certain packets as priority or not priority depending on
how much traffic you have injected into the network through that
particular port.
Part of the issue here is that when you start treating packets
distinguishably, the routers now have to look at every packet and make
decisions about how to treat them. They do that today for purposes of
routing, but now they have to do it for other purposes of managing the
quality of the service. [The router has to ask:] Do I keep this packet, do
I forward it, do I discard it, how many packets of this type have already
been processed? Is this customer getting more than he subscribed to,
should I therefore push back?
Those are CPU-intensive decisions that have to be made. So in order to
offer these kinds of differential qualities of service, we possibly have to
upgrade our CPUs and the routers that are doing the work.
LT: When will this be available?
Cerf: The assured-access-rate service is being brought up on Concert
Internet Plus. We will roll it out to the domestic network either late this
year or during 1998 for the general user population. |
