Mailing List Archive: NANOG: users

absense of multicast deployment

Index | Next | Previous | View Threaded

jabley at isc

Mar 3, 2006, 12:42 PM

Post #1 of 8 (1927 views)
Permalink

absense of multicast deployment

On 3-Mar-2006, at 11:48, Stephen Sprunk wrote:

> That depends on your perspective. There's a compelling need for
> usable multicast in many environments, and so far there's nobody
> (in the US) with a compelling need for IPv6, much less shim6.

If there's such a compelling need for native multicast, why has it
seen such limited deployment, and why is it available to such a tiny
proportion of the Internet?

Joe

stephen at sprunk

Mar 3, 2006, 1:01 PM

Post #2 of 8 (1818 views)
Permalink

Re: absense of multicast deployment [In reply to]

Thus spake "Joe Abley" <jabley [at] isc>
> On 3-Mar-2006, at 11:48, Stephen Sprunk wrote:
>> That depends on your perspective. There's a compelling need for usable
>> multicast in many environments, and so far there's nobody (in the US)
>> with a compelling need for IPv6, much less shim6.
>
> If there's such a compelling need for native multicast, why has it seen
> such limited deployment, and why is it available to such a tiny
> proportion of the Internet?

Just because it's not widely available on the public network doesn't mean
that it's not widely available on private networks connected to the public
one. There are tens of millions of users out there with access to Cisco
IP/TV, Real, etc. over multicast, not to mention custom business apps
(particularly common in the securities world) that use multicast. They're
self-contained, though, so you don't see the packets/users or even know
they're out there.

I'm not terribly surprised the public Internet doesn't have real mcast yet;
the cost to build replicating unicast servers is paid by content sources
while the cost to deploy PIM SSM is paid by another, and as such the cheaper
alternative doesn't necessarily win. In a private network, one org can see
the total costs for both and pick whichever one makes more sense.

If anything, it's in ISPs interests to keep things unicast since there's
more bits to bill for. At least until someone figures out how to bill for
the traffic exiting the network at the other end (and that still leaves a
problem for peering).

S

Stephen Sprunk "Stupid people surround themselves with smart
CCIE #3723 people. Smart people surround themselves with
K5SSS smart people who disagree with them." --Aaron Sorkin

tme at multicasttech

Mar 3, 2006, 1:02 PM

Post #3 of 8 (1816 views)
Permalink

Re: absense of multicast deployment [In reply to]

Hello;

By everything I can tell, it's roughly about 10% for global
deployment, see

http://www.multicasttech.com/status

and is becoming basically BCP in the enterprise IPTV environment
(which are currently all
"walled gardens"). (Note that this deployment is effectively entirely
ASM / IGMP v2.)

By any measure, multicast deployment is much larger than IPv6
deployment at present, and it is growing.
I will be glad to argue the point to any length you might desire.

Of course, the deployment did not exactly take the form that was
anticipated in 2000...

Regards
Marshall

On Mar 3, 2006, at 3:42 PM, Joe Abley wrote:

>
> On 3-Mar-2006, at 11:48, Stephen Sprunk wrote:
>
>> That depends on your perspective. There's a compelling need for
>> usable multicast in many environments, and so far there's nobody
>> (in the US) with a compelling need for IPv6, much less shim6.
>
> If there's such a compelling need for native multicast, why has it
> seen such limited deployment, and why is it available to such a
> tiny proportion of the Internet?
>
>
> Joe
>

brandon at rd

Mar 3, 2006, 1:06 PM

Post #4 of 8 (1819 views)
Permalink

Re: absense of multicast deployment [In reply to]

> If there's such a compelling need for native multicast, why has it
> seen such limited deployment

It hasn't been needed by enough people

We have a growing need and are doing a little bit to encourage use

http://www.bbc.co.uk/multicast/

Other content owners agree, we have a number working on joining us
(sadly I can't mention names until they're live)

This is a work in progress (it's been live for two weeks), we have a
long way to go.

When I see a need for V6 and it looks viable I'll try and do the
same for it. As it's only doing something we can do already it'll
be a harder sell.

brandon

jtk at ultradns

Mar 3, 2006, 4:00 PM

Post #5 of 8 (1806 views)
Permalink

Re: absense of multicast deployment [In reply to]

On Fri, Mar 03, 2006 at 04:02:00PM -0500, Marshall Eubanks wrote:
> By everything I can tell, it's roughly about 10% for global
> deployment, see
>
> http://www.multicasttech.com/status

10% by one measure. That is perhaps the most positive spin on
what we can see. All that tells us is the AS view. To some
extent netblocks, but that is really still based on origin AS
also. It says nothing about which interfaces inside and behind
an AS have PIM enabled and that is what really matters. I suspect
real multicast reachability and deployment is quite a bit lower than
10%. I have no idea how to go about measuring it though, but 10%
would have to be the best we could do if all hidden interfaces were
enabed.

> By any measure, multicast deployment is much larger than IPv6
> deployment at present, and it is growing.
> I will be glad to argue the point to any length you might desire.

You know me Marshall, I care about multicast, but I'm not sure
I'd go around comparing multicast to IPv6, that doesn't help. :-)

John

eddy+public+spam at noc

Mar 3, 2006, 5:18 PM

Post #6 of 8 (1810 views)
Permalink

Re: absense of multicast deployment [In reply to]

JA> Date: Fri, 3 Mar 2006 15:42:25 -0500
JA> From: Joe Abley

JA> If there's such a compelling need for native multicast, why has it
JA> seen such limited deployment, and why is it available to such a tiny
JA> proportion of the Internet?

One could ask the same of long-prefix PI availability and announcement.
Lack of demand is not the only answer; one must also examine technical
and policy constraints.

Taking your statement a step further, though, you have a very good
point: A smart approach is to analyze end-user wishes and demands,
transform the "wish list" into engineering requirements, and take it
from there. (e.g., just what is the global table asymptotic limit?)

Eddy
--
Everquick Internet - http://www.everquick.net/
A division of Brotsman & Dreger, Inc. - http://www.brotsman.com/
Bandwidth, consulting, e-commerce, hosting, and network building
Phone: +1 785 865 5885 Lawrence and [inter]national
Phone: +1 316 794 8922 Wichita
________________________________________________________________________
DO NOT send mail to the following addresses:
davidc [at] brics -*- jfconmaapaq [at] intc -*- sam [at] everquick
Sending mail to spambait addresses is a great way to get blocked.
Ditto for broken OOO autoresponders and foolish AV software backscatter.

kurtis at kurtis

Mar 4, 2006, 4:42 AM

Post #7 of 8 (1815 views)
Permalink

Re: absense of multicast deployment [In reply to]

On 3 mar 2006, at 22.02, Marshall Eubanks wrote:

> By any measure, multicast deployment is much larger than IPv6
> deployment at present, and it is growing.
> I will be glad to argue the point to any length you might desire.

There are also operators that are deploying IPv6 just so that they
can do multicast to their end-users without have to figure out how to
run it through NAT. As was discussed at the last SANOG in some of the
workshops.

- kurtis -

david.b.israel at xo

Mar 4, 2006, 7:26 AM

Post #8 of 8 (1803 views)
Permalink

RE: absense of multicast deployment [In reply to]

> If there's such a compelling need for native multicast, why
> has it seen such limited deployment, and why is it available
> to such a tiny proportion of the Internet?

Other reasons have already been posted, but I wanted to throw mine in:
Because multicast was designed from an organizational (presumably a
university) point of view, not from the core. When you have a protocol
designed that way, you get assumptions about the Internet topology that
aren't necessarily true, the biggest one being that there is some root
node at the top that connects you to the cloud, and you work down from
there. If you have a copule of root nodes, it still works fine, but if
you're in the core, with peer connections instead of root nodes,
handling several orders of magnitude more connections, it ceases to work
so nicely. So another answer to your question is that, while people
would love to do multicast, it is fundimentally broken in a
wide-deployment scenario. It simply doesn't scale to Internet size yet,
despite the numerous protocols that have been thrown at the problem.
Big backbones don't want to deploy a broken protocol that few people use
over wide ranges, and individual sites don't want to develop for a
broken protocol that big backbones aren't deploying. When somebody
fixes the protocol, in such a way that it still provides a benefit to
the transmitter and all the interested end stations can use it, then
we'll see wide deployment.

This scenario can be applied to almost any protocol/technology that
folks want to see deployed and can't understand why it hasn't been yet.
Naming the biggest example is left as an exercise for the reader.

-Dave

Index | Next | Previous | View Threaded

Interested in having your list archived? Contact Gossamer Threads