On Sun, Feb 03, 2002 at 03:00:03PM -0600, Chris Adams wrote:
Okay, I'm with a (decent sized, although probably small by NANOG measures) ISP. Why do I want to turn on multicast (what does it get me that I don't have today)?
Do you want a technical spin or the www.showmethemoney.com spin ? The basis of the technical spin is that ip multicast is as much ip as ip unicast and that as such it need to be provided for applications to leverage all the benefits of the ip service. The basis of the money spin is that you as an ISP are making money (hopefully) by shuffling bits out onto links (to customers) who are paying for the links, and you are paying for traffic on backbone links where you connect to the core, and ip multicast allows you to shuffle more bits out from your network on the links to customers without linearly increasing the amount of bits on your uplinks. Practically speaking, there a small but fair amount of ip multicast content out on the network that you could have your customers receive, mostly entertainment oriented, but you're not really limited by this. Given that the primary purpose of ip multicast for you is to give you a savings in bandwidth, you might as well look into encouraging your customers to put up content - especially if there are likely candidates that are interesting to your regional customer space - after all, live content today often does not exist at good quality because the need to use some existing splitter technology drives up the cost to the content producer in such a way that it's not feasible. Also, you could convert unicast content at the uplink of your network into multicast so as to save pulling it in multiple times into your network.
And if I want to turn it on, where can I find the resources you mention?
There's a couple of books out there, but the config recommendation would mostly come from your gear vendor like they'll probably come too for most of the other features you've got on your routers. If you use cisco gear, check out "www.cisco.com/go/ipmulticast", or ask on cisco-multicast@andrew.cmu.edu. Also, check out with your uplink ISPs, you should easily be able to get up and running by having an ip multicast enabled isp give you the config recommendation. Getting ip multicast to run this way is not particularily challenging, it is more the problem of getting the right cooking recipe and the three pointers above should lead you there pretty well. Cheers Toerless