A schedule defends from chaos and whim
— ANNIE DILLARD
From arranging vacations to making appointments, we are constantly scheduling activities. A busy router is no exception. Routers must schedule the handling of routing updates, management queries, and, of course, data packets. Data packets must be scheduled in real time by the forwarding processors within each line card. This chapter concentrates on the efficient scheduling of data packets while allowing certain classes of data packets to receive different service from other classes.
Returning to our picture of a router (Figure 14.1), recall that packets enter on input links and are looked up using the address lookup component. Address lookup provides an output link ...