PON: Threat or What?
I’ve been listening to people who know stuff talk about PON (Passive Optical Networks), a bit of infrastructure that (perhaps!) threatens to provide a strong incentive to providers not to scale up the amount of bandwidth they grant us. But I’m in way over my head. Here’s what I think I know:
A connectivity provider uses PON to split light (data) over multiple lines. Each subscriber receives all the same data, ignoring the packets not tagged for that particular subscriber. So, you have to build security into the network — Smart! Bad! — to keep A from reading B’s bits.
The insidious problem: PON is difficult/expensive to upgrade. As a result, the PON network suppliers will have an incentive to keep traffic down by filtering and limiting services.
(There’s no unique problem with PON with regard to the fact that it centralizes control, for whoever owns the cable is in a position to control content whether they use PON or not.)
PON is not yet widely deployed. There is a set of towns in Utah entertaining PON bids for providing municipal-licensed cable, and there are maybe some other examples. Primarily, PON is now showing up in responses to RFPs from the ILECs.
Corrections and slap downs gratefully accepted.
(If you’re not sure why smart networks are bad networks, read the original End-to-End argument, Isenberg’s “stupid network” or Doc’s and my World of Ends.)
Categories: Uncategorized dw
David,
I don’t know much about PONs in particular, and their definition is certainly not yet well formed or well understood, but it seem to me that some of what you say doesn’t really follow. In particular you said:
“Each subscriber receives all the same data, ignoring the packets not tagged for that particular subscriber.”
That part is fine. Then you say:
So, you have to build security into the network — Smart! Bad! — to keep A from reading B’s bits.”
I can’t see how the second part follows from the first. It’s pretty easy to encrypt the data separately for each subscriber. Then each subscriber, not the network, does the decryption.
OK, sure, this encryption is at the link level and not end-to-end, but this is very similar to what 802.11 does. So in this respect PONs are quite similar to most wireless systems, such as 802.11.
There are other issues with PONs, but the one you mention doesn’t seem to be a problem.
— Jim
Hi David!
at the risk of entering a bidirectional debate between two parties who don’t really know what they are talking about —
my understanding of the concern around PON was that it is a master/slave networking technology *masquerading* as a peering network (namely ethernet). That is, you would buy a nic for “carrier-grade ethernet” and find that you couldn’t NAT or set up a web server or anything else that the carrier on the other end of the link didn’t want you do do.
It sounded to me as if it was a fancy, glass wire to plug into your dumb terminal…