# Bits and Queues

Introduction :: Codes :: Bounds

## Achievability of the bound

It can also be shown (with a lot of work!) that for an queue, the upper bound can be achieved when the input process is Poisson with rate λ.

Thus

## Information-bearing channels

We now generalize to the case where each packet actually carries some kind of information (e.g., bits). I will mostly summarize the results. Let the channel have information-bearing capacity
*
C
*
_{
0
}
in nats/sec.

Observe that if
*
C
*
_{
0
}
is sufficiently large, then the λ that maximizes capacity is equal to μ, so no information is carried in the timing. Combining some theorem, we find:

Pretty cool!