[j-nsp] cable modem/dsl/ftth bandwidth limiting

[Chris Kawchuk]

Layer-2 Cable is done at a BRAS (running in DHCP mode). Layer-3 Cable Plants shape at the CMTS.

Layer-2 Optical/GPON/FTTH can be done at a BRAS (if DHCP or PPP), or can be done at the head end GPON device; assuming the GPON is reasonably 'smart', and understands each subscriber and their associated consumer profiles.

Think VoIP. Need to shape from the network-side before it hits the last-mile, so that any SIP/IAD traffic (for a CPE device with a built-in IAD) never gets dropped as well. Toss IPTV into the mix, and yes, QoS/Shaping must happen prior to the last-mile. (unless you like pixelated TV when your bittorrent client is also going full blast =)..)

Remember that Authentication also needs to happen (who's allowed on the network, either by PPP l/p or DHCP Mac); as well as traffic counters, so that those who do metered--billing (i.e. Australia) can get per-subscriber utilization. So, whichever device is holding the "next hop" gateway IP for the subscriber is also the device that is doing the downstream shaping; so that the utilization counters match what the subscriber has actually used.

- CK.


On 2012-06-20, at 6:46 AM, Chris Evans wrote:

> cable and ftth