zlacker

>>alden5+(OP)
So that is "432 Mbit/s per laser, and 9000 lasers total". I don't know you guys but I find that statement much more relatable than "42 PB/day". Interestingly, they also say each laser "can sustain a 100Gbps connection per link" (although another part of the article even claims 200 Gbit/s). That means each laser is grossly underused on average, at 0.432% of its maximum capacity. Which makes sense since 100 Gbit/s is probably achievable in ideal situations (eg. 2 satellites very close to each other), so these laser links are used in bursts and the link stays established only for a few tens of seconds or minutes, until the satellites move away and no longer are within line of sight of each other.

And with 2.3M customers, that's an average 1.7 Mbit/s per customer, or 550 GB per customer per month, which is kinda high. The average American internet user probably consumes less than 100 GB/month. (HN readers are probably outliers; I consume about 1 TB/month).

>>mrb+b46
> That means each laser is grossly underused on average, at 0.432% of its maximum capacity.

Don't forget that every communication protocol has fixed and variable overhead.

The first is a function of the packet structure. It can be calculated by simply dividing the payload capacity of a packet by the total number of bits transmitted for that same packet.

Variable overhead is more complex. It has to do with transactions, negotiations, retries, etc.

For example, while the theoretical overhead of TCP/IP is in the order of 5%, actual overhead could be as high as 20% under certain circumstances. In other words, 20% of the bits transmitted are not data payload but rather the cost of doing business.