[9137] in North American Network Operators' Group
Re: Multicast
daemon@ATHENA.MIT.EDU (Matthew V. J. Whalen)
Tue May 6 16:18:10 1997
To: "Matt Ranney" <mjr@ranney.com>
cc: Aleph One <aleph1@dfw.net>, nanog@merit.edu
In-reply-to: Your message of "Tue, 06 May 1997 10:30:39 PDT."
<Pine.LNX.3.95.970506102317.19519G-100000@wacky.eit.com>
Date: Tue, 06 May 1997 15:36:37 -0400
From: "Matthew V. J. Whalen" <mwhalen@uucom.com>
I think I heard "Matt Ranney" say:
>On Tue, 6 May 1997, Aleph One wrote:
>
>> Morning all. I was wondering if anyone could comment on how deployed is
>> multicast routing in real-world networks. How many of you have enabled
>> multicast routing in your core routers? Do you offer this as a service to
>
>All the sites that I'm familiar with are still using tunnels. Some of
>those tunnels might be homed on dedicated routers instead of a
>Unix/mrouted machine, but I'd be somewhat surprised if anybody ran
>native multicast in their core routers.
>
>People pay for unicast traffic, and its not worth messing up that
>unicast traffic for a fun multicast experiment that'll crash your
>router or run it out of memory ever other day.
I've heard of several ISPs running native multicast on their core routers
since it's more efficient than using tunnels, but still using tunnels for
inter-domain multicast connectivity. It seems to me that most ISPs would
rather use multicast and have traffic traverse their backbone just once than
use point-to-point connections for several identical data feeds. I think
saying that multicast will "crash your router" might be a harsher statement
than is necessary (but I'm not saying that Cisco (and other vendors) haven't
had their share of screwups). PIM in later releases of the IOS hasn't
inherently unstable, but of course, it must be configured properly. :)
-matthew
mwhalen@uucom.com
Shop as usual...........................and avoid panic buying
