From: Scott Morris (swm@emanon.com)
Date: Fri Apr 02 2004 - 13:11:06 GMT-3
"Administratively scoped" is a vague term. The 239.0.0.0/8 range is also
known as private multicasts. They aren't allowed on the internet (in theory
anyway). You, in your own network, may decide to hijack some multicast
groups, and therefore you'll need to make those administratively scoped as
well if you're connected to the Internet using multicast. That avoids
confusion. But it makes it entirely up to you!
There are a few scopes that are largely defined:
224.0.0.0/24 = local link multicasts
232.0.0.0/8 = source specific multicasts
233.0.0.0/8 = GLOP (AS-based multicasts)
239.0.0.0/8 = private multicasts (kinda like the 10., 172., and 192.168.
addresses)
There are probably others that I'm forgetting, but the bottom line is that
for your own network, you scope things however you do. It's just when you
decide to interconnect with others that you have to play by the agreed-upon
standards or rules. Otherwise, any decision you make is inherently
"administratively scoped".
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, CISSP,
JNCIS, et al.
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
swm@emanon.com/smorris@ipexpert.net
http://www.ipexpert.net
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Scott, Tyson C
Sent: Friday, April 02, 2004 10:32 AM
To: Craig Dorry; ccielab@groupstudy.com
Subject: RE: Multicast Boundary command
But Craig you are also stating what my question is. The groups you are
stating are what I understand as administratively scoped addresses. In some
of the practice labs I have done they have used the boundary command to
block addresses in the 224.0.0.0/8 range. From what I understand this is
not in the administratively scoped range. So am I wrong or is the help
topic in IOS wrong?
R4(config-if)#ip multicast ?
Boundary Boundary for administratively scoped multicast addresses
Regards,
Tyson Scott
-----Original Message-----
From: Craig Dorry [mailto:chdorry@yahoo.com]
Sent: Friday, April 02, 2004 7:33 AM
To: Scott, Tyson C; ccielab@groupstudy.com
Subject: Re: Multicast Boundary command
Tyson - I think you are misinterpreting the "administratively scoped"
addresses. I have used the boundary command in the following way:
Multiple campuses running multicast, so we defined 3 "administrative scopes"
(3 different blocks of multicast addresses) from the 239.0.0.0/8 block of
addresses - campus local (never leaves the campus), regional (stays within
the United States), and global.
The boundary was applied to the "campus local" which is multicast groups
where all sources and receivers are at the same physical campus. In this
case we used the same scope for all campus local multicast at each campus.
So on the connections from the Campus to the MAN we used the ip multicast
boundary 1 command, and then defined access-list 1 deny 239.1.0.0
0.0.255.255 and permit everything else. (239.1.0.0/16 groups were to never
leave the campus)
Hope this helps.
--- "Scott, Tyson C" <tyson.scott@hp.com> wrote:
> Group,
>
> I am confused as to the topic of the use of Boundary with
> Multicast. When you use the help from IOS it says it is for
> administratively scoped Multicast addresses. I thought the
> administratively scoped addresses where 239.0.0.0 to 239.255.255.255.
> So does this command only apply to this range or is the help menu
> misleading?
>
>
>
> R4(config-if)#ip multicast ?
>
> Boundary Boundary for administratively scoped
> multicast addresses
>
>
>
> Regards,
>
> Tyson Scott
>
>
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