RE: PIM BIDIR

In a network you will always have some routers that see the /32 anycast as
ECMP. They will look to only one as the RP. Therefore the BiDir topology
will be broken/split at these locations. Everywhere else they will have a
single topology, split by the RP they have closest to them. Half your
network will have one topology and the other will have another. The two
won't meet.

David

--
http://dcp.dcptech.com
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> Joe Astorino
> Sent: Tuesday, January 26, 2010 9:03 AM
> To: David Prall
> Cc: Scott Morris; ron.wilkerson_at_gmail.com; Carlos G Mendioroz; Hans
> None; ccielab_at_groupstudy.com
> Subject: Re: PIM BIDIR
> 
> I'm confused.  Are we playing a gameshow :P  But for the records,
> BiDir PIM doesn't use the concept of (S,G) groups so the sharing of
> sources between RPs is sort of broken.
> 
> On Tue, Jan 26, 2010 at 8:59 AM, David Prall <dcp_at_dcptech.com> wrote:
> > Joe,
> > Correct response.
> >
> > And why does anycast break BiDir PIM?
> >
> > David
> >
> > --
> > http://dcp.dcptech.com
> >
> >
> >> -----Original Message-----
> >> From: Joe Astorino [mailto:jastorino_at_ipexpert.com]
> >> Sent: Tuesday, January 26, 2010 8:54 AM
> >> To: David Prall
> >> Cc: Scott Morris; ron.wilkerson_at_gmail.com; Carlos G Mendioroz; Hans
> >> None; ccielab_at_groupstudy.com
> >> Subject: Re: PIM BIDIR
> >>
> >> Thank you!  OK -- Typically you can do this with something known as
> >> Phantom RP.  With phantom RP you have a few options.
> >>
> >> 1) The "phantom" RP is actually not a real router : )  Yes, I know
> it
> >> sounds insane.  The RP in bi-dir PIM does not have to be a specific
> >> physical router.  It can be an entity -- basically a subnet.  As
> long
> >> as people can get to the subnet, they can reach the "RP"
> >>
> >> 2) Phantom RP with longest match -- In this case you will assign
> >> multiple routers the same loopback address but with different masks.
> >> So say your RP is 1.1.1.1
> >>    R1: 1.1.1.1/32
> >>    R2: 1.1.1.1/30
> >>    R3: 1.1.1.1/29
> >>
> >> due to the longest prefix match rules, you have redundancy.
> >>
> >> On Tue, Jan 26, 2010 at 8:46 AM, David Prall <dcp_at_dcptech.com>
> wrote:
> >> > With all of the non-english speaking individuals that make up
> >> groupstudy I
> >> > find it funny we can even think about proper English grammar.
> >> >
> >> > Now back to BiDir PIM. Can anyone tell me how you provide for RP
> >> redundancy
> >> > in a BiDir environment, using static RP configuration?
> >> >
> >> > David
> >> >
> >> > --
> >> > http://dcp.dcptech.com
> >> >
> >> >> -----Original Message-----
> >> >> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On
> Behalf
> >> Of
> >> >> Scott Morris
> >> >> Sent: Tuesday, January 26, 2010 8:02 AM
> >> >> To: Joe Astorino
> >> >> Cc: ron.wilkerson_at_gmail.com; Carlos G Mendioroz; David Prall;
> Hans
> >> >> None; ccielab_at_groupstudy.com
> >> >> Subject: Re: PIM BIDIR
> >> >>
> >> >>  I find it more ironic that a list just full of wonderful grammar
> >> >> lesson
> >> >> candidates decides to take the time to actually worry about this
> >> one!
> >> >> IMHO, I would not consider Joe to be one of the "big offenders".
> >> >>
> >> >> ;)
> >> >>
> >> >> Joe Astorino wrote:
> >> >>
> >> >>   OK -- I find it "interesting" that David and I thought of the
> same
> >> >>   thing.  Jesus Christ...
> >> >>
> >> >>   On Tue, Jan 26, 2010 at 7:48 AM,    <ron.wilkerson_at_gmail.com>
> >> >> wrote:
> >> >>
> >> >>     Carlos is questioning your use of the word ironic and
> rightfully
> >> >> so.  Very cool that gs provides grammar lessons here and there.
> :)
> >> >>
> >> >>     -----Original Message-----
> >> >>     From: Joe Astorino     <jastorino_at_ipexpert.com>    Date: Tue,
> 26
> >> >> Jan 2010 07:15:33
> >> >>     To: Carlos G Mendioroz    <tron_at_huapi.ba.ar>    Cc: David
> Prall
> >> >> <dcp_at_dcptech.com>    ; Hans None    <acsyao_at_hotmail.com>    ;
> >> >> <ccielab_at_groupstudy.com>    Subject: Re: PIM BIDIR
> >> >>
> >> >>     Yep , just saying it was ironic how David and I thought of
> the
> >> same
> >> >> thing.
> >> >>
> >> >>     On Tue, Jan 26, 2010 at 7:06 AM, Carlos G Mendioroz
> >> >> <tron_at_huapi.ba.ar>     wrote:
> >> >>
> >> >>       Where is the irony ?
> >> >>       Networks are graphs, and when you need a cycle free set of
> >> arcs
> >> >> (links)
> >> >>       that connect all the nodes (routers/switches) you are
> looking
> >> for
> >> >>       a spanning tree. It's all already defined in mathematics,
> and
> >> we
> >> >>       are reusing already defined terms :) (thanks God we did not
> >> >> reinvent
> >> >>       the wheel once !!!)
> >> >>
> >> >>       Dijkstra was never thinking of cisco when he did SPF algo
> >> either.
> >> >>
> >> >>       -Carlos
> >> >>
> >> >>       Joe Astorino @ 25/01/2010 21:09 -0300 dixit:
> >> >>
> >> >>         It will forward up to the RP via the DF interface.
> >>  Ironically
> >> >> I sort
> >> >>         of think about it like spanning-tree too.  The DF is sort
> of
> >> >> like your
> >> >>         designated port -- It is the best path up to the RP.  So
> the
> >> >> multicast
> >> >>         starts sending and hits a router, and goes UP the
> multicast
> >> >> tree
> >> >>         (hence the bi-dir term) towards the RP via the DF
> interface.
> >> >> Once the
> >> >>         RP gets the information it will be sent DOWN the shared
> tree
> >> to
> >> >>         receivers.
> >> >>
> >> >>         On Mon, Jan 25, 2010 at 3:55 PM, David Prall
> >> >> <dcp_at_dcptech.com>         wrote:
> >> >>
> >> >>           Based on what interface the multicast packet was
> received
> >> on.
> >> >> The RP sets
> >> >>           the root of the tree and that is all in BiDir. I like
> to
> >> >> think of BiDir as
> >> >>           Spanning-Tree for IP Multicast, with the RP being the
> >> root.
> >> >>
> >> >>           --          http://dcp.dcptech.com
> >> >>
> >> >>             -----Original Message-----
> >> >>             From:             nobody_at_groupstudy.com             [
> >> >> mailto:nobody_at_groupstudy.com            ] On Behalf Of
> >> >>             Hans None
> >> >>             Sent: Monday, January 25, 2010 3:47 PM
> >> >>             To:             ccielab_at_groupstudy.com
> >>  Subject:
> >> >> PIM BIDIR
> >> >>
> >> >>             All,
> >> >>
> >> >>             When a non RP router received a mcast packet, where
> >> should
> >> >> the router
> >> >>             forward
> >> >>             the packet? Toward the RP or toward the mcast group
> OIL?
> >> >>
> >> >>             My question is, how will a non RP router pin point
> its
> >> own
> >> >> position?
> >> >>             Whether
> >> >>             it was in the path from the source to RP or from RP
> to
> >> the
> >> >> destination
> >> >>             group?
> >> >>
> >> >>             Thanks,
> >> >>
> >> >>             Hans
> >> >>
> >> >>
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> _______________________________________________________________________
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> >> >>
> >> >>       --
> >> >>       Carlos G Mendioroz        <tron_at_huapi.ba.ar>        LW7 EQI
> >> >> Argentina
> >> >>
> >> >>     --
> >> >>     Regards,
> >> >>
> >> >>     Joe Astorino CCIE #24347 (R&S)
> >> >>     Sr. Technical Instructor - IPexpert
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> >> >>
> >> >>
> >> >>
> >> >
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Regards,
> >>
> >> Joe Astorino CCIE #24347 (R&S)
> >> Sr. Technical Instructor - IPexpert
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> >>
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> >
> >
> 
> 
> 
> --
> Regards,
> 
> Joe Astorino CCIE #24347 (R&S)
> Sr. Technical Instructor - IPexpert
> Mailto: jastorino_at_ipexpert.com
> Telephone: +1.810.326.1444
> Live Assistance, Please visit: www.ipexpert.com/chat
> eFax: +1.810.454.0130
> 
> IPexpert is a premier provider of Classroom and Self-Study Cisco CCNA
> (R&S, Voice & Security), CCNP, CCVP, CCSP and CCIE (R&S, Voice,
> Security & Service Provider) Certification Training with locations
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