Network: honest shape, strategic size

Why does network price follow the topology but not physics in size?

Network price is the least physical line on the list. Its shape is honest: a step function over the boundaries data crosses.

same host → same rack → same AZ → cross-AZ → cross-region → internet

These are the same boundaries that set latency. But the size of the steps is strategic: internet egress runs roughly an order of magnitude above wholesale transit (what the vendor pays for bandwidth). The price gradient follows how well each boundary locks your data in place, not what each boundary costs to cross. Treat data gravity (the tendency of data to attract compute to itself because moving it is expensive) as the intended product of the pricing, not an accident.

The strongest evidence that this is policy and not physics: it changed under regulatory pressure. Egress charges for leaving a vendor entirely went to zero across the major vendors in 2024, without any change in the underlying networks.

One structural note: cross-AZ charges are the first place where independence gets an explicit invoice. A well-known design principle says that independence (copies that fail separately) is never free: you always pay for it in money, latency or complexity. Here the payment is itemized per byte, forever.