[kwlug-disc] Cable internet providers

[Andrew Kohlsmith (mailing lists account)]

On Jun 4, 2014, at 10:56 PM, unsolicited <unsolicited at swiz.ca> wrote:
> Andrew's note also reminds me - we forget, cable internet / Rogers has up to something like 10 subscribers on the same piece of cable in a loop. (Unlike Bell twisted pair / point to point.) [Thus a Rogers subscriber can attack their Rogers neighbour directly, while Bell subscribers can't. Seems to me there's even specific language about this in the Rogers/resellers ToS/ToU.]

This isn’t possible with DOCSIS3; the modems are quite solidly locked down and normal traffic between any modem and the head end isn’t seen by anyone else on the same physical link. I *do* think that broadcast traffic is still seen, but there really isn’t much there except for the odd NetBIOS broadcasts by old computers connected directly to the modem.

It’s a lot like a standard LAN with the exception that it’s practically impossible to put the NIC into promiscuous mode. :-)

> Seems to me I remember encountering this first when people were looking for redundant internet service. It never made sense to me to bind a 5Mbps telco twisted pair with a +8Mbps cable internet (evenly distributed load balancing by rotating TCP sessions would always leave one going faster than the other, so some other scheduling schema was going to make more sense.) At the same time, it didn't make sense to me if going for redundancy to depend upon the same physical piece of copper. (Dual cable internet service.)

A long, long time ago I managed to figure out how to extrude multi-homed IP space over 1+n IPSec connections. The idea was that you’d have any number of internet connections to some location (cable, dsl, wireless, even dialup) and each connection would establish a VPN link to the extruder. The extruder’s job was to (if I recall now) proxy arp the far end IP address and route traffic for it over whichever connection seemed the best to send it over. The far end router’s job was to route traffic for that multi-homed IP over whichever connections were up and least loaded.

It worked extremely well for what it was, but I’ll be damned if I can figure out how I did it. This was a good 10+ years ago. I do remember that it involved proxyarp, IPSec and iproute2 and it provided a very reliable connection without wasting the aggregate/redundant connection bandwidth.

> So, the Rogers TV box is also just a digital (network) terminal on the private backbone, delivering/translating audio/video out.

Yep.

> And why I call their home phone VoIP - which is what it is. Private endpoint be darned. To heck with marketing speak. It's all just VoIP!

Cell phones are just about VoIP as well; But as with any VoIP system if you can guarantee data delivery you won’t be able to tell the difference between a traditional circuit-switched network and the packet-switched networks we take for granted today. The trick, of course, lies in guaranteeing bandwidth (and latency).

-A.