From: Imal kalutotage (imal.kalutotage@gmail.com)
Date: Sat Nov 05 2005 - 03:53:00 GMT-3
Nice explanation Andy,
So what do we need to do to overcome this problem..in NBMA
2 solutions comes to my mind.
1. static mroute to the source, pointing towards hub
2. Spoke to spoke tunnel
Am I right on this, I just need to verify my thinking..
Cheers
Imal
On 11/5/05, Edwards, Andrew M <andrew.m.edwards@boeing.com> wrote:
>
> If they're congruent then there would be no issue for spt failover on
> the leaf router.
>
> The main issues are this:
>
> Did you pass the RPF to the BSR/AUTORP mapper?
> Did you pass the RPF towards the RP?
> Did you pass the RPF towards the source of (S,G) for the default SPT
> failover?
>
> As indicated, SPT failover is the default behavior for a router in
> sparse mode.
>
> So, it will build a SPT to the source NOT the RP by default.
>
> What does this mean? It means we spent a lot of time setting up the
> routers to pass the RPF check for the RP in order to get your first
> response to a test packet on the group. However, once you send data to
> the group, the leaf (end routers) will by default change from using the
> RP to the SPT and potentially stop receiving (symptomatically we see
> them stop responding) to the test data.
>
> This can be a problem is the route to the Source for the group is out a
> different interface than where you are receiving it from. IOW, you
> failed the RPF check and stop passing data because the paths to RP and
> Source (S,G) are not congruent.
>
> This can happen on NBMA topologies where there is a known route towards
> a source that is NOT directly connected (e.g. its reachable via another
> spoke on hub and spoke frame cloud at L2, but at L3 looks like its
> directly attached).
>
>
> Andy
>
> -----Original Message-----
> From: Balogh, Jim [mailto:jim.balogh@gwl.com]
> Sent: Friday, November 04, 2005 4:43 PM
> To: Chris Lewis; kevin gannon; ccielab@groupstudy.com
> Subject: RE: Sparse mode multicast ?
>
>
> Not sure....good question! Anyone know?
>
> Jim
>
> ________________________________
>
> From: Chris Lewis [mailto:chrlewiscsco@yahoo.com]
> Sent: Friday, November 04, 2005 5:29 PM
> To: Balogh, Jim; kevin gannon; ccielab@groupstudy.com
> Subject: RE: Sparse mode multicast ?
>
>
> what if the shared tree and source tree are congruent?
>
> Chris
>
> "Balogh, Jim" <jim.balogh@gwl.com> wrote:
>
> Kevin,
>
> Just gave the scenario a quick glance, and you need the ip pim
> spt-threshold command on the last-hop router....in this case R2.
>
>
> The switch from shared to source tree (with Sparse Mode) happens
> upon
> the arrival of the first data packet at the last hop router.
> This switch
> occurs because the ip pim spt-threshold interface configuration
> command
> controls that timing, and its default setting is 0 kbps.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> Behalf Of
> kevin gannon
> Sent: Wednesday, November 02, 2005 12:12 PM
> To: ccielab@groupstudy.com
> Subject: Re: Sparse mode multicast ?
>
> Anyone any ideas ?
>
> Regards
> Kevin
>
> On 11/1/05, kevin gannon wrote:
> > Have a simple set with three routers
> >
> > R2--------R5(RP)--------R3
> >
> > Its running all sparse mode. R2 has an igmp join statement for
>
> > 225.25.25.25 <http://225.25.25.25> and R3 is sending a ping to this
> group source
> from
> > 35.35.35.3 <http://35.35.35.3>. Below is the mroutes I see on R3 the
> source of the
> stream.
>
> > I am experimenting with set the spt threshold to infinity on
> R3 below
> > is the different mroute
> > outputs:
> >
> > Default setup no SPT threshold changed
> > ####################################################
> > (*, 225.25.25.25 <http://225.25.25.25>), 00:36:46/stopped, RP
5.5.5.5<http://5.5.5.5>,
> flags: SJPCL
> > Incoming interface: Serial0/1, RPF nbr 35.35.35.5 <http://35.35.35.5>
> > Outgoing interface list: Null
> >
> > (35.35.35.3 <http://35.35.35.3>, 225.25.25.25 <http://225.25.25.25>),
> 00:05:20/00:02:59, flags: PLT
> > Incoming interface: Serial0/1, RPF nbr 0.0.0.0 <http://0.0.0.0>,
> Registering
> > Outgoing interface list: Null
> >
> > (*, 224.0.1.40 <http://224.0.1.40>), 00:37:22/stopped, RP
5.5.5.5<http://5.5.5.5>,
> flags: SJPCL
> > Incoming interface: Serial0/1, RPF nbr 35.35.35.5 <http://35.35.35.5>
> > Outgoing interface list: Null
> >
> > SPT Threshold set to infinity
> > ###################################################
> >
> > (*, 225.25.25.25 <http://225.25.25.25>), 00:40:15/stopped, RP
5.5.5.5<http://5.5.5.5>,
> flags: SPCL
> > Incoming interface: Serial0/1, RPF nbr 35.35.35.5 <http://35.35.35.5>
> > Outgoing interface list: Null
> >
> > (35.35.35.3 <http://35.35.35.3>, 225.25.25.25 <http://225.25.25.25>),
> 00:08:49/00:02:58, flags: PLT
> > Incoming interface: Serial0/1, RPF nbr 0.0.0.0 <http://0.0.0.0>,
> Registering
> > Outgoing interface list: Null
> >
> > (*, 224.0.1.40 <http://224.0.1.40>), 00:40:51/stopped, RP
5.5.5.5<http://5.5.5.5>,
> flags: SPCL
> > Incoming interface: Serial0/1, RPF nbr 35.35.35.5 <http://35.35.35.5>
> > Outgoing interface list: Null
> >
> > My questions:
> > 1. Why do I not see any outgoing interfaces in either output
> > for (35.35.35.3 <http://35.35.35.3>, 225.25.25.25 <http://225.25.25.25>
> ),
> >
> > 2. In the default SPT setup how come I see the "Registering"
> > going on and on and on.....
> >
> >
> > Thanks & Regards
> > Kevin
>
>
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