From: CCIEin2006 (ciscocciein2006@gmail.com)
Date: Mon Feb 27 2006 - 18:29:14 GMT-3
Hmm kinda sounds like sparse mode with the spt-threshold set to infinity....
On 2/27/06, Bob Sinclair <bob@bobsinclair.net> wrote:
>
> BIDIR is a strange beast:
>
> Unlike Dense mode, Bidir does not flood to all PIM neighbors, only up the
> shortest path tree to the RP. If there are no clients who want traffic,
> then Dense will prune back. BIDIR only prunes back to the RP, then the RP
> drop it. Traffic continues to be forwarded from the source to the RP as
> long as it is active. Receivers join much like regular sparse-mode:
> explicit joins toward the RP.
>
> BIDIR is a lot like spanning-tree: think of RPF interface as root port;
> think of DF interface as designated port. Basic rule then is if a port is
> not RPF or DF, then it cannot forward for the group. In fact, BIDIR is
> similar to Core Based Tree, which Radia Perlman had a hand in developing.
>
> Good for many-to-many multicast because it minimizes state.
>
> Try labbing it up and doing some "debug ip mpacket". Just enable
> globally (ip pim bidir-enable) and add the "bidir" keyword to your RP
> statements.
>
>
> Bob Sinclair
> CCIE #10427, CCSI 30427
> www.netmasterclass.net
>
>
> ----- Original Message -----
> *From:* CCIEin2006 <ciscocciein2006@gmail.com>
> *To:* Bob Sinclair <bob@bobsinclair.net>
> *Cc:* ccielab@groupstudy.com
> *Sent:* Monday, February 27, 2006 1:24 PM
> *Subject:* Re: Difference between Bidirectional PIM and PIM Sparse Mode
>
>
> Hi Bob,
>
> Since the first hop routers forward the traffic whether its wanted or not,
> isn't that like dense mode?
>
> Do receivers still send joins to the RP?
>
> What does the RP do with the traffic if there are no receivers - send a
> prune?
>
> Thanks!
>
> On 2/27/06, Bob Sinclair <bob@bobsinclair.net> wrote:
> >
> > Bidirectional PIM Differs from Sparse mode in at least these ways:
> >
> > Bidir does not maintain any (S,G) state. Only (*,G) state. This is
> what
> > makes it scalable for many-to-may multicast.
> >
> > Bidir does not do PIM registration. First-hop routers do not register
> > traffic with the RP. First hop routers, forward traffic for active
> groups
> > toward the RP, whether anyone wants the traffic or not, as long as the
> group
> > is active.
> >
> > Since there is no PIM registration, the RP does not actually have to be
> a
> > reachable address, only a reachable network that acts as a root.
> >
> > Here is a link with more info:
> >
> >
> >
>
>
http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration
> _guide_chapter09186a00800ca796.html
> >
> >
> > HTH,
> >
> > Bob Sinclair
> > CCIE #10427, CCSI 30427
> > www.netmasterclass.net
> >
> >
> > ----- Original Message -----
> > *From:* CCIEin2006 <ciscocciein2006@gmail.com>
> > *To:* ccielab@groupstudy.com
> > *Sent:* Monday, February 27, 2006 11:28 AM
> > *Subject:* Difference between Bidirectional PIM and PIM Sparse Mode
> >
> >
> > Hello group,
> >
> > I am not very clear on the differences between Bidirectional PIM and PIM
> > Sparse Mode. Both use the RP and switchover to shortest path tree after
> > the
> > first packet is received, correct?
> >
> > How do they differ exactly?
> >
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