Multicast Grouping

March 31, 2008 @ 10:09 pm · Filed under CCIE Study

Hello Joseph,
Thanks a lot for the examples. I appreciate taking the time for that. However, for the 44 example you meant 3,4, and 6 right? Regards,

From: shinepjoseph@iprimus.com.auTo: mike.haddad@hotmail.com; ccielab@groupstudy.comSubject: RE: Multicast GroupingDate: Mon, 31 Mar 2008 12:07:16 +1100

Mike,
No. you can ahave any value from 0 to 255 for the wild cards. I will give you a couple of examples.
The wild card 12 is valid, but would match only the 3rd and 4th bits from LSB from right most. That is, when you write them in binary, it becomes 0000 0000 0 0000 0100 4 0000 1000 8 0000 1100 12
So when you use this wild card in an access-list it matches only these 4 addresses.
A wild card of 44 means either 0 or 1 on the bit positions 3, 5, 6 or in binary
0000 0000 0 0000 0100 4 0000 1000 8 0000 1100 12 0010 0000 32 0010 0100 36 0010 1000 40 0010 1100 44
Thus, the wild card of 44 matches the above 8 addresses.
HTH, Shine

From: Mike Haddad [mailto:mike.haddad@hotmail.com] Sent: Monday, 31 March 2008 11:51 AMTo: Shine Joseph; ccielab@groupstudy.comSubject: RE: Multicast Grouping
Hello Shine, You’re right and as long as I understand the valid wildcards are : 1 3 7 15 31 63 127 and 255. So using a wild card of 12 is considered invalid? Thanks,> From: shinepjoseph@iprimus.com.au> To: mike.haddad@hotmail.com; ccielab@groupstudy.com> Subject: RE: Multicast Grouping> Date: Sun, 30 Mar 2008 22:09:38 +1100> > Mike,> > Write them in binary.> 226 - 1110 0010> 12 - 0000 1100> > The possible combinations would be:> 1110 0010 - 226> 1110 0110 - 230> 1110 1010 - 234> 1110 1110 - 238> > So by having a mask of 12 you are are matching only above 4 addresses.> > HTH,> Shine> > > —–Original Message—–> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Mike> Haddad> Sent: Sunday, 30 March 2008 5:55 PM> To: ccielab@groupstudy.com> Subject: Multicast Grouping> > Hello,> > I still don’t understand why the below ACL can’t be grouped:> interface Loopback0> ip pim sparse-dense-mode> !> ip pim send-rp-announce Loopback0 scope 16 group-list 50> !> access-list 50 permit 226.0.0.0 1.255.255.255> access-list 50 permit 228.0.0.0 3.255.255.255> access-list 50 permit 232.0.0.0 3.255.255.255> access-list 50 permit 236.0.0.0 1.255.255.255> access-list 50 permit 238.0.0.0 0.255.255.255> > > Why can’t we group them as:> access-list 50 permit 226.0.0.0 12.255.255.255> > Thanks for the clarification,> > _________________________________________________________________> Enter the Hunt & you could win a 2008 Eclipse Spyder! Click here to enter!> http://g.msn.ca/ca55/213> >

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