Subject: RE: [pim] Update_SPTbit(S,G)

From: "James Huang" <[email-masked]>
Date: Thu, 27 Jun 2002 14:35:58 -0700

In the Upstream (S,G) state-machine.
When it moves from the Joined state to the NotJoined state (because JoinDesired(S,G) becomes FALSE),
it will set SPTbit(S,G) to FALSE.

James Huang

> -----Original Message-----
> From: Ju, Yu [mailto:[email-masked]]
> Sent: Thursday, June 27, 2002 2:29 PM
> To: James Huang; Ju, Yu; [email-masked]
> Subject: RE: [pim] Update_SPTbit(S,G)
> 
> 
> Where in the draft say that? Please point it out to me.
> 
> Yu
> 
> > -----Original Message-----
> > From: James Huang [mailto:[email-masked]]
> > Sent: Thursday, June 27, 2002 5:24 PM
> > To: Ju, Yu; [email-masked]
> > Subject: RE: [pim] Update_SPTbit(S,G)
> > 
> > 
> > SPTbit(S,G) will be set to FALSE when JoinDesired(S,G) 
> becomes FALSE.
> > This will allow the switch back from the SPT tree to RPT tree.
> > 
> > James Huang
> > 
> > > -----Original Message-----
> > > From: Ju, Yu [mailto:[email-masked]]
> > > Sent: Thursday, June 27, 2002 2:15 PM
> > > To: [email-masked]
> > > Subject: [pim] Update_SPTbit(S,G)
> > > 
> > > 
> > > Hi,
> > > 
> > > When a packet arrives, the (S,G) SPTbit is updated as follows:
> > > 
> > >      void
> > >      Update_SPTbit(S,G,iif) {
> > >        if ( iif == RPF_interface(S)
> > >              AND JoinDesired(S,G) == TRUE
> > >              AND ( DirectlyConnected(S) == TRUE
> > >                    OR RPF_interface(S) != RPF_interface(RP)
> > >                    OR inherited_olist(S,G,rpt) == NULL
> > >                    OR RPF'(S,G) == RPF'(*,G) ) ) {
> > >           Set SPTbit(S,G) to TRUE
> > >        }
> > >      }
> > > 
> > > So if the condition is not satisfied, the SPTbit(S,G) is not 
> > > set to TRUE and
> > > keep its previous value which could be TRUE. 
> > > So once SPTbit(S,G) is set to TRUE, it will never be set back 
> > > to FALSE until
> > > (S,G) state times out.  Am I right? Is this why PIM-SM does 
> > > not provide a
> > > mechanism to switch back from SPT tree to RPT tree?
> > > 
> > > 
> > > Thanks,
> > > 
> > > Yu
> > > _______________________________________________
> > > pim mailing list
> > > [email-masked]
> > > http://catarina.usc.edu/mailman/listinfo/pim
> > > 
> > 
> 
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